WO2010072541A1 - Crosslinking of organopolysiloxane compound present on a substrate with gaseous aldehyde reagent - Google Patents

Abstract

The invention provides a process for crosslinking organopolysiloxane compound (S) which is present on a substrate and has at least one group of the general formula (1): -R1-NHR2, in which the organopolysiloxane compound (S) is contacted with gaseous aldehyde reagent (A) of the general formula (2): O=CH-R3, where R1, R2 and R3 are each as defined in claim 1, and the substrate comprising the organopolysiloxane compound (S) crosslinked with gaseous aldehyde reagent (A) by the process according to claims 1 to 6.

Description

 Crosslinking of substrate-based organopolysiloxane compound with gaseous aldehyde reagent

The present invention relates to a process for crosslinking organopolysiloxane compound having amino groups on a substrate with gaseous aldehyde reagent.

Silicone or silicone-containing formulations and composites are known and are used in the form of films, coatings and coatings in large quantities for modification and

Equipment of different materials and fibers used. In their range of properties, silicones or silicone-containing formulations are superior to purely organic films, coatings and coatings in many respects. Thus, the use of silicone products leads to an extensive improvement of otherwise unavailable but generally desirable properties such as flow behavior, gas permeability, abrasion resistance, hydrophobicity, smoothness, feel or gloss of the treated substrate.

A major problem of all coatings, but in particular of limited in their chemistry silicone coatings, is the often lack of adhesion to the respective treated substrate (so-called permanence of the coating). As a result, the coating can be removed either simply mechanically, for example by rubbing or rubbing, or by chemical stress, for example contact with various solvents and / or exposure to certain pH environments (as occur, for example, in washing processes), can solve again from the substrate. One approach to solving the problem of lack of permanence is to crosslink the individual silicone polymer chains both with each other and with the substrate to be treated, thus increasing the mechanical and chemical resistance and thus the permanence of the overall system.

Crosslinking and binding to the substrate can be effected both by non-covalent interactions and by covalent bonds.

Among the non-covalent interactions, hydrogen bonds in particular have become established. These provide, for example, in the form of urethane or urea groups within the group of thermoplastic silicone elastomers with each other for increased network density and by interaction with also hydrogen bond forming groups of the substrate (e.g., hydroxy moieties on cellulose surfaces) also for some fixation. The preparation and use of such thermoplastic silicone elastomers are described in detail, inter alia, in EP 0 606 532 A1 and EP 0 342 826 A2.

Another noncovalent crosslinking mechanism is based on acid-base interactions between Lewis basic / Lewis acidic groups of the silicone polymer with Lewis acidic / Lewis basic groups of the substrate or polymer. Examples of these are amino-functional silicone oils which, as is known, have a positive influence in particular on hydrophobicity and softness of textiles and, because of their Lewis-basic amino functionalities, have the property of being 'absorbed' onto the Lewis acidic fibers. Such silicone amine oils and their applications are described for example in EP 1555011 A. Both mechanisms have in common that their produced permanence is only temporary and inadequate and the coating can be easily removed both mechanically and chemically,

Significantly better permanence is achieved when the

Fixation of polymer and substrate or crosslinking of polymer with each other by the formation of covalent bonds occurs.

A covalent crosslinking can be carried out, for example, by the fact that the silicone polymers already in the preparation by

Use of e.g. be crosslinked trifunctional building blocks. However, the resulting polymers are thereby adversely affected in their processing properties (e.g., melt viscosities, moldability, solubility in an application aid). Also, a fixation to the substrate is usually no longer possible. A subsequent fixation / crosslinking following a successful application is therefore always useful.

Such subsequent fixation / crosslinking may be effected, for example, by the presence of alkoxysilyl groups in the silicone polymer which provide better permanence by hydrolysis and condensation with hydroxy groups of the substrate or hydroxy groups of other silicone polymers. Such alkoxysilyl-containing silicone polymers are described for example in EP 1544223 Al. However, the Si-O-C or Si-OE bonds (E = element of the substrate) which are formed in the connection to the substrate are as a rule hydrolysis-labile and therefore easy to reopen, as a result of which a good permanence, in particular in an aqueous medium, is usually not given. A formation of comparatively stable siloxane bonds Si On the other hand, O-Si as a rule again requires prior treatment of the substrate with corresponding silanes.

In paper and film coating, two systems have been established industrially based on thermally curable crosslinking mechanisms.

The historically preferred form is mechanistically based on condensation crosslinking. This type of crosslinking takes place by reaction of SiOH groups of corresponding silicone polymers, which are crosslinked with SiH-containing crosslinkers to form hydrogen, generally tin-catalyzed.

A disadvantage of these systems, in addition to the unwanted formation of hydrogen, the slow reaction time, so that usually when rolling up the coated goods, the silicone systems are not cured, which can for example lead to a back transfer of the silicone. This, in turn, has poor printability due to follow-up processes.

Mainly because of this, systems have become established in recent years which crosslink by means of a noble metal-catalyzed hydrosilylation reaction. In this case, alkylene-functionalized silicone polymers are used which vulcanize by means of noble metal (usually platinum) with an SiH-containing crosslinker without by-product formation. Within seconds, the reaction leads to a material that has hardened very well on an industrial scale. For example, reference is made here to the document US 4772515. Primarily due to the rapid rise in precious metal prices in recent years, the economic viability of this technology has been seriously challenged, leading to an intensive search for alternatives. All coating systems used are multi-component, consisting at the minimum of a silicone polymer, a crosslinker and a catalyst. In the case of noble metal-catalyzed systems, an inhibitor is also required which generates an acceptable processing time. Above all, the balance of the inhibition at room temperature with simultaneously high reactivity at elevated temperature makes such systems generally disadvantageous.

The systems can be solvent-based, solvent-free or water-based. Due to the improved environmental and safety-relevant processing, solvent-free systems are to be preferred. Water-based systems are without alternative in the direct siliconization during papermaking, since the aqueous production process requires an analogous water-based silicone system. Industrial emulsions are used.

Another crosslinking mechanism which is already known in the field of purely organic polymers concerns the so-called Λ / -methylol crosslinking. In this case, polymers are produced by copolymerization with suitable monomers which carry Λ / -Methylolamidgruppen. These are known to bind covalently to alcoholic groups even at lower temperatures in the absence of water at elevated temperature or in the presence of acidic catalysts. Likewise, they can react with each other and thus cause a crosslinking of the polymer. In both cases, covalent ether bonds are formed, which are known to be very strong and are only broken again under extreme physical or chemical stress. This effect is utilized, for example, by EP 0 143 175 A, which produces polymer dispersions via free-radical emulsion polymerization, which are over are nachvernetzbar the methylol mechanism discussed above.

Although Λ / -methylol groups can in principle be prepared by reacting amines units with formaldehyde, as a rule, however, the reaction leads to polymeric condensation products, so that polymeric networks ultimately result via imine intermediates. This reaction of amines with formaldehyde has already been described: US Pat. No. 3,461,100 describes condensation products of aldehydes and primary diamines and monoamines. The resulting high polymer condensation products are discussed as protective coatings. DE 10047643 A1 describes polymeric condensation products of aldehydes and silicon amines, which are, however, exclusively high polymer and highly crosslinked. In both documents, the product is already high polymer after implementation. It is thus no longer a reactive form, as it is the monoaddition product of a formaldehyde molecule to an amine, and is therefore no longer available for subsequent reactions on substrates or post-crosslinking reactions with each other.

In contrast, stabilized silicone emulsions or stabilized silicone solutions containing Λ / -methylolated structural units are basically capable of post-crosslinking in the sense described above.

Thus, US Pat. No. 3,433,536 A describes the Λ / methylolation of terminal and lateral amidoalkyl-polysiloxanes by treating them with aqueous formaldehyde solution in the presence of methanol, thereby producing both the corresponding Λ / -methylolamidoalkyl-polysiloxanes and the corresponding Λ / -methylol-methyl ethers to be obtained. Generally, such amide However, based Λ / -methylols and especially their ethers often have significantly reduced reactivities in the subsequent crosslinking and / or substrate fixation in comparison with N-methylols derived from corresponding amines, carbamates or ureas.

The invention relates to a process for the crosslinking of organopolysiloxane compound (S) present on a substrate which comprises at least one group of the general formula (1)

-R ¹ -NHR ² (1)

in which the organopolysiloxane compound (S) is reacted with gaseous aldehyde reagent (A) of the general formula (2)

O = CH-R- (2),

wherein R is a divalent hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and with -CN or - Halogen may be substituted;

2

R is a hydrogen atom, a hydrocarbon radical having 1 to 20

4 5 6 C atoms, a - (CO) -OR group or a - (CO) -NR R group, where the carbon chain is formed by non-adjacent - (CO) -, -O-, -S- or - NR groups can be interrupted and substituted with -CN or -halogens; R is a hydrogen atom, a hydrocarbon radical having 1 to 20

C atoms, the carbon chain is not

8 adjacent - (CO), -0-, -S- or -NR groups may be interrupted and substituted with -CN or -halogen;

₄ R is a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S or NR groups and may be substituted by -CN or -halogen;

R is a hydrogen atom, a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and may be substituted by -CN or -halogen and may be covalently linked to R;

R is a hydrogen atom, a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and may be substituted by -CN or -halogen and may be covalently linked to R;

R is a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain by non-adjacent - (CO) -, -0-, -

8th

S- or -NR groups may be interrupted and substituted with -CN or -halogen; and

Q

R is a hydrocarbon radical having 1 to 20 C atoms;

2 with the proviso that either R is a hydrogen atom or

1 2 at least one of the radicals R or R in the direct vicinity of their jointly bonded nitrogen atom carries a - (C = O) group. The procedure is suitable for both

Organopolysiloxane compound (S) coated as well as impregnated substrates. Since the organopolysiloxane compound (S) first on the substrate with the gaseous aldehyde reagent (A) in

Contact is made, the crosslinking reaction takes place directly on the to be coated or impregnated

Substrate. Due to the spatial separation of

Organopolysiloxane compound (S) as a reactive polymer component and gaseous aldehyde reagent (A) as a crosslinking component ensure unlimited storage stability of the organopolysiloxane compound (S). The critical in other processes pot lives for coating or impregnation with

Organopolysiloxane compound (S) are also completely bypassed.

As gaseous aldehyde reagents (A) can be used, for example. at 20 ° C or elevated temperatures monomer present forms of aldehydes, such as formaldehyde gas, for example, developed from aqueous or organic solution or other latent formaldehyde sources such as paraformaldehyde, trioxane or other formaldehyde condensates. Also, an aldehyde derivative such as glyoxal can be used.

3

R is preferably a hydrogen atom or alkyl or aryl radicals each having 1 to 10 C atoms, more preferably a methyl radical or a hydrogen atom.

Preferably, R is a divalent alkyl group

, Cycloalkyl-alkenyl, aryl or arylalkyl radical, in particular alkyl radical having in each case 1 to 6 C atoms, particularly preferably

CH2 and - (CH2) 3-. 2

R is preferably a hydrogen atom or an alkyl, cycloalkyl, alkenyl, aryl or arylalkyl radical

4 having 1 to 20 C atoms, a - (CO) -OR group or a - (CO) -

NR R group, more preferably around the hydrogen atom.

₄ R is preferably an alkyl, cycloalkyl,

Alkenyl, aryl or arylalkyl radical, in particular alkyl radical having 1 to 6 C atoms, particularly preferably the methyl radical.

R and / or R are preferably hydrogen atoms or alkyl, cycloalkyl, alkenyl, aryl or arylalkyl radicals, in particular alkyl radicals each having 1 to 6 C atoms, more preferably the hydrogen atom.

R is preferably alkyl, cycloalkyl,

Alkenyl, aryl or arylalkyl radicals, in particular alkyl radical having 1 to 6 C atoms, particularly preferably the methyl radical.

8 R is preferably alkyl, cycloalkyl, alkenyl, aryl or

Arylalkyl, in particular an alkyl radical having 1 to 6 carbon atoms, more preferably a methyl radical.

The organopolysiloxane compound (S) used preferably contains units of the general formula (3)

9 R _a AbSi0 (4- _a _b / 2)

wherein g R is a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S or NR groups and may optionally be substituted by -CN or -halogen ; R has the above meanings, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3 and

A represents a group of the general formula (1), with the proviso that the sum a + b is less than or equal to 3 and the organopolysiloxane compound (S) has at least one unit of the general formula (3) with b different zero.

G

R is preferably alkyl, cycloalkyl, alkenyl, aryl or arylalkyl radicals, preferably alkyl or aryl radicals each having 1 to 6 C atoms, more preferably the methyl, ethyl, vinyl or phenyl radical. a is preferably 2 or 1 and b is preferably 0 or 1.

Halogen radicals in the context of the present invention are preferably fluorine, chlorine, bromine.

The organopolysiloxane compound (S) comprises both polymeric, oligomeric and dimeric organopolysiloxane compounds.

The viscosity of the organopolysiloxane compounds (S) is preferably at least 50, more preferably at least 100 mPa.s and preferably at most 5000, more preferably at most 1500 mPa.s, in each case at 25 ° C.

The organopolysiloxane compounds (S) used are preferably substantially linear polysiloxanes having terminal and / or pendant monovalent radicals A and / or chain-containing bivalent radicals A, where A is the has the abovementioned meaning. In the case of the substantially linear polysiloxanes, preferably at most 5%, in particular at most 1%, of the siloxane units are branching units.

Particularly preferred are the ones having

Organopolysiloxane compounds (S) to those of the general formula (4)

9 9 9 9

AeR 3- _e Si0- (SiR 2θ) _m - (SiAR O) _n -SiR 3 _e Ae (4),

in which

9

A and R have the meanings given above; e is 0 or 1; m is 0 or an integer of 1 to 200; n is 0 or an integer of 1 to 200, and m + n is 0 or an integer of 1 to 400; with the proviso that at least one radical A is present per molecule.

Preferably, in the general formula (4), the individual

9 9

Units (SiR 2θ) _m and (SiAR O) _n in the molecule statistically distributed. m + n is preferably at least 5, more preferably at least i, and preferably at most 500, most preferably at most 250.

G

The ratio of the groups A: R is preferably at least 1: 10,000, in particular at least 1: 1000 and preferably at most 1: 5, in particular at most 1: 30. Crosslinking of the organopolysiloxane compound (S) with the gaseous aldehyde reagent (A) leads to crosslinking units

1 2 3 2 1 of the general formula -R-NR-CHR-NR-R -.

Crosslinking can be carried out, for example, after application of the organopolysiloxane compound (S) by customary methods of application by gassing with the aldehyde reagent (A). This contacting can be carried out at any temperature, preferably at 20 ° C or higher temperatures, more preferably at temperatures of at least 80 ° C, especially at least 100 ° C and preferably at most 180 ° C.

The contacting with the aldehyde reagent (A) preferably lasts at most 200 seconds, more preferably at most 10 seconds.

The contacting as well as the networking can be just as static under a mobile atmosphere of gaseous

Aldehyde reagent (A) take place. The contacting as well as the crosslinking can be carried out under any pressure of the atmosphere of gaseous aldehyde reagent (A), preferably at pressures of 0.01 to 1 MPa, in particular under normal pressure (0, 10 MPa).

The aldehyde reagent (A) containing atmosphere may consist of gaseous aldehyde in pure form as well as other gaseous components. As further gaseous components, for example, air, nitrogen, argon or steam can be used.

Depending on the rate of the crosslinking reaction, essentially due to the reactivity of the organopolysiloxane compound (S), it may also be advantageous to the organopolysiloxane compound (S) to add a catalyst for the crosslinking reaction. In principle, all Lewis and Bronsted acids are suitable as catalyst. These can be added directly to the silicone or applied as a separate component.

The substrates impregnated or coated with the crosslinked organopolysiloxane compound (S), preferably papers and films, can be used for example for all classical release applications. By way of example, label applications, baking paper, medical sector, adhesive tapes, hygiene and graphic area are to be mentioned.

The substrates impregnated or coated with the crosslinked organopolysiloxane compound (S) may, for example, also be textiles and leather.

The substrates impregnated or coated with the organopolysiloxane compound (S) may also be finely divided, e.g. Powder or granules, and be connected by the organopolysiloxane compound (S) as a binder to a shaped body.

The invention also provides the substrate containing the organopolysiloxane compound (S) crosslinked by the process with gaseous aldehyde reagent (A).

Examples

Unless otherwise indicated, all quantities and

Percentages based on weight, all pressures 0.10 MPa (abs.) And all temperatures 20 ° C.

1. paper coating The respective (aminoalkyl) polydimethylsiloxane (see Figure 1 & Table 1) is coated on a Glassine paper substrate (see Table 2) with a 20 μm doctor blade. Subsequently, the coated paper is contacted for 30 seconds at 140 ° C. in a gassing chamber with a continuous flow of gaseous formaldehyde and argon generated from an aqueous solution of formaldehyde (37%) with the aid of a passed-through argon stream. The formaldehyde mass flow is 200 mg / min. The curing takes place immediately. The resulting siliconized papers are tested according to standard FINAT methods (see Table 2).

Figure 1: (Aminoalkyl) polydimethylsiloxanes 1 - 3

- S Ii-I L- OS Ii- JI-m OS Ii- | ^L -OS I-J I -m OS Ii-f JOS I-f'm-OS ii-IL-OS I-1 _m OS ιi

NH ₂ NH ₂ NH _J

(Aminoalkyl) polydimethylsiloxane 1: m ~ 35

(Aminoalkyl) polydimethylsiloxane 2: m ~ 65

(Aminoalkyl) polydimethylsiloxane 3: m ~ 45

Table 1: (Aminoalkyl) polydimethylsiloxanes

Table 2: Application test after FINAT on glassine paper Silca Classic (Ahlstrom company)

2. Folien-Beschichtung

2. Foil coating

The respective (aminoalkyl) polydimethylsiloxane (see Figure 1) is applied with a 20 μm doctor blade to the respective corona-pretreated film substrate (see Tables 3 - 5). The coated film is then heated for 30 s at 90, 105 or 130 ° C. (see Tables 3 -5) in a gassing chamber with a continuous stream of gaseous formaldehyde and argon, generated from an aqueous solution of formaldehyde (37%) with the aid of a passed through argon stream, contacted. The formaldehyde mass flow is 200 mg / min. The curing takes place immediately. The resulting siliconized films are tested according to standard FINAT methods (see Tables 3 - 5).

Table 3: Application test on HDPE film according to FINAT (company orbit) at 90 ⁰ C.

Tabelle 4: Anwendungstest nach FINAT auf BOPP-Folie CR 50

Table 4: Application test according to FINAT on BOPP film CR 50

(From Innovia) at 105 ⁰ C

Table 5: Application test according to FINAT on PET film RN 36 (company

Mitsubishi) at 130 ^° C.

Claims

claims A method of crosslinking on a substrate Organopolysiloxane compound (S) containing at least one group of general formula (1) -R ¹ -NHR ² : D in which the organopolysiloxane compound (S) is reacted with gaseous aldehyde reagent (A) of the general formula (2) O = CH-R ³ (2), wherein R is a divalent hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and with -CN or - Halogen may be substituted; 2 R is a hydrogen atom, a hydrocarbon radical having 1 to 20 4 5 6 is C atoms, a - (CO) -OR group or a - (CO) -NR R group, where the carbon chain is formed by non-adjacent - (CO) -, -O-, -S- or - NR groups can be interrupted and substituted with -CN or -halogens; 3 R is a hydrogen atom, a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain by not Q adjacent (CO), -0-, -S- or -NR groups may be interrupted and substituted with -CN or -halogen; 4 R is a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S or NR groups and may be substituted by -CN or -halogen; R is a hydrogen atom, a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and may be substituted by -CN or -halogen and may be covalently linked to R; 6 R is a hydrogen atom, a hydrocarbon radical having 1 to 20 C atoms, wherein the carbon chain may be interrupted by non-adjacent - (CO) -, -0-, -S- or -NR groups and substituted with -CN or -halogen, and may be covalently linked to R; R is a hydrocarbon radical having 1 to 20 carbon atoms, wherein the carbon chain by non-adjacent - (CO) -, -0-, - 8th S- or -NR groups may be interrupted and substituted with -CN or -halogen; and 8th R is a hydrocarbon radical having 1 to 20 C atoms; 2 with the proviso that either R is a hydrogen atom 1 2 or at least one of the radicals R or R in direct Neighboring to its shared nitrogen atom carries a - (C = O) group. 2. The method of claim 1, wherein the gaseous aldehyde reagent (A) formaldehyde gas is used. 3. The method according to claim 1 or 2, wherein R is -CH ₂ - or - (CH ₂ ) 3- means. 2 4. The method of claim 1 to 3, wherein the R a Means hydrogen. 5. The method of claim 1 to 4, wherein the Organopolysiloxane compounds (S) of the general formula (4) 9 9 9 9 AeR 3- _e Si0- (SiR 2θ) _m - (SiAR O) _n -SiR 3-eAe (4) correspond, where g A and R have the meanings given in claim 1; e is 0 or 1; m is 0 or an integer of 1 to 200; n is 0 or an integer of 1 to 200, and m + n is 0 or an integer of 1 to 400; with the proviso that at least one radical A is present per molecule. 6. The method of claim 1 to 5, wherein the contacting of organopolysiloxane compound (S) with gaseous aldehyde reagent (A) at 20 ° C to 180 ° C. 7. Substrate comprising the organopolysiloxane compound (S) crosslinked by the process according to claims 1 to 6 with gaseous aldehyde reagent (A). Substrates according to claim 7, selected from papers and films.