DE102007054003A1 - Polyurethane-elastomer obtained by reacting 1,5-naphthalene diisocyanate and polysuccinate polyol and converting the obtained isocyanate-prepolymer with chain elongator, useful as polyurethane molded part or coating - Google Patents

Abstract

Polyurethane-elastomer obtained by reacting 1,5-naphthalene diisocyanate and polysuccinate polyol with a molar mass of 500-5000 g/mol and an average functionality of 1.95-2.25 and subsequently converting the obtained isocyanate (NCO)-prepolymer with short chain hydroxyl group exhibiting chain elongator with a molar mass of 62-450 g/mol and functionality of 2 or 3 or water, is claimed.

Description

The The present invention relates to polyurethanes (PUR) based on 1,5-naphthalene diisocyanate (NDI) and succinic acid polyesters and a process for their preparation.

PUR based on 1,5-naphthalene (z. B. Desmodur ^® 15 from Bayer MaterialScience AG) have long been known and are commercially marketed under the trade name Vulkollan ^® preferred in high-quality applications. Vulkollane ^® distinguish themselves here by their excellent mechanical-dynamic properties as well as their outstanding durability compared to many other materials. Also, the swelling behavior in many organic solvents is at a remarkably low level.

The use of NDI for the production of cast elastomers is also known and z. In DE-A 169 41 69 described. This polyester polyols whose softening temperatures are in the range of 60 to 145 ° C, used.

Out JP 198 911 9484 A It is apparent that polymalonates, polysuccinates or polyglutarates having molecular weights of 500 to 5000 Da by reaction with p-phenylene diisocyanate and / or cyclohexane diisocyanate and hydroxyl-containing chain extenders, preferably from the group of dihydric and trihydric alcohols, to the construction of PU elastomers with particular favorable swelling behavior can be used against organic solvents.

A In this context, printing inks pose a particular challenge In particular, in screen printing, in which one of an elastic Material manufactured squeegee is permanently in contact with printing inks and at the same time mechanically stressed, is a material desirable, the two requirements in a special way does justice.

task The present invention was therefore to PUR materials available to provide, compared to the previous systems an improved Swelling behavior, especially in printing inks and otherwise at least equivalent properties compared to conventional Show systems.

conventional Systems in this context are essentially those that as a long-chain polyol component polyadipate polyester and as a crosslinker usually contain short-chain polyols having two or three hydroxyl groups.

Surprisingly It was found that polyurethanes then a particularly favorable Swelling behavior, especially in printing inks, if at otherwise the same recipe turbine components instead of the polyadipate polyols Polysuccinatpolyole, (polyester of succinic acid) used become.

object The present invention therefore PUR elastomers based on 1,5-naphthalene diisocyanate (A), polysuccinate polyols having molecular weights of 500 to 5000 Da and average functionalities from 1.95 to 2.25 (B) and short chain Hydroxyl-containing chain extenders with molecular weights from 62 to 450 Da and functionalities from 2 to 3 or Water (C).

PU elastomers, in particular cast elastomers based on 1,5-naphthalene diisocyanate are used in industrial practice via an intermediate stage, prepared the NCO prepolymers. NCO prepolymers are NCO groups terminated polyols obtained by reacting a polyol with a polyisocyanate in, based on functional groups, molar Isocyanate excess at room temperature to about 100 ° C (in the specific case of the NDI in question here also about 100 ° C) to the constancy of the NCO value.

A important application of such NCO-terminated prepolymers the production of elastomers, in particular after the casting process, where the prepolymers either directly after their preparation chain extended, d. H. with a short-chain polyol - z. B. 1,4-butanediol - or reacted with water, or the NCO prepolymers, if advantageously possible, to a lower temperature (Storage temperature) for the purpose of a later chain extension cools and stores.

In principle, PU elastomers, in particular cast elastomers, can be obtained not only by the prepolymer process but also by the one-shot process in which a mixture of long and short-chain polyols is reacted with polyisocyanates. The disadvantage here is that in particular especially when using high-melting polyisocyanates, such as. B. NDI, only inferior elastomers can be obtained since not attached to the polyols adducts of short-chain polyol (chain extender) and high-melting polyisocyanate (eg NDI) partially precipitate from the reaction melt, thus removed from further reaction and the ordered further molecular weight prevent. This is one reason why the prepolymer process normally results in better products.

Farther is favorable in the synthesis via prepolymers, that part of the heat of reaction already by the prepolymer step is anticipated and thus the exothermic in the actual polymer structure smaller fails. This has a favorable effect on the speed the molecular weight structure and allows longer Casting times, so represents a processing advantage.

• A) 1,5-Naphthalindiisocyanat (NDI),
• B) Polysuccinatpolyolen mit Molmassen von 500–5000 Da und mittleren Funktionalitäten von 1,95 bis 2,25,
• C) Hydroxylgruppen aufweisenden Kettenverlängerern mit Molmassen von 62 bis 450 Da und Funktionalitäten von 2 bis 3 oder Wasser,

wobei die Komponenten A) und B) zunächst zu NCO-Prepolymeren mit einem NCO-Gehalt von 2,5 bis 6 Gew.-% umgesetzt werden und anschließend mit den Kettenverlängerern oder Wasser C) unter Einhaltung einer Kennzahl von 1,04 bis 1,25 zum PUR-Elastomeren umgesetzt werden.Another object of the invention is a process for the preparation of PU elastomers, preferably by the casting method, based on

• A) 1,5-naphthalene diisocyanate (NDI),
• B) polysuccinate polyols having molecular weights of 500-5000 Da and average functionality of 1.95 to 2.25,
• C) hydroxyl-containing chain extenders having molecular weights of from 62 to 450 Da and functionalities of from 2 to 3 or water,

wherein the components A) and B) are first reacted to NCO prepolymers having an NCO content of 2.5 to 6 wt .-% and then with the chain extenders or water C) while maintaining a ratio of 1.04 to 1, 25 are reacted to PUR elastomers.

The Key figure is calculated from the quotient of the number of NCO groups of the diisocyanate to the total number of OH groups of (B) and (C); in the case of using water will instead of the number of OH groups from (C) the number of OH groups from (C) multiplied by 2 is used.

The PUR elastomers of NDI and polysuccinate polyols according to the invention have a very high solvent resistance, especially against organic solvents, and are far superior to the previously known PUR elastomers.

The B) Polysuccinatpolyole mentioned in accordance with the state the technique preferably by polycondensation of succinic acid, Succinic anhydride and / or succinic esters with volatile alcohols, such as. Methanol, ethanol, Propanol or butanol with molar excess polyol produced. Molar are excess polyols Polyols with molecular weights of 62 to 300 Da, with 2 to 12 C atoms and Functionalities of at least 2, branched or unbranched may be and their hydroxyl groups are primary or are secondary. These polyols can also be ether groups exhibit. Typical representatives are ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol-1,4, butanediol-2,3, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol and higher homologs, dipropylene glycol, tripropylene glycol and higher homologues and oligo-tetrahydrofurans with hydroxyl end groups. Of course, mixtures can also be used become.

at The preparation of polysuccinate polyols may be in addition to mentioned molar excess polyols and polyether polyols with molecular weights of 300 to 3000 Da in proportions of less than 15% by weight be used in the mixture. However, the exclusive is preferred Use of polyols with molecular weights of 62 to 300 Da, very special preferably those having 2 to 6 carbon atoms, such as. As ethylene glycol-1,2, diethylene glycol and triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, Butanediol-2,3, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol and 3-methyl-pentanediol-1,5 and dipropylene glycol and mixtures thereof.

Next of succinic acid may have a maximum of 5% by weight of others Acids from the group consisting of aliphatic, araliphatic or aromatic dicarboxylic acids in the synthesis of polysuccinate polyols be.

The Production of the polyester polyols B) takes place according to the state the technique at elevated temperature in the range of 150 up to 250 ° C and under application of a vacuum of 1 to 100 mbar, preferably using an esterification or transesterification catalyst, wherein the reaction is completed to such an extent that the Acid number is below a value of 3 mg KOH / g.

The preparation of the prepolymers is preferably carried out such that the polysuccinate on a Temperature is heated from 80 to 160 ° C and stirred with NDI. The exact starting temperature for the prepolymer formation depends on the size of the batch and the type of vessel and is determined in preliminary experiments so that a maximum temperature is reached due to the exothermicity of the reaction, which is sufficient to melt the solid NDI used in the reaction mixture or to obtain a clear homogeneous melt. The required temperature maximum is in the range of 120 to 135 ° C, more preferably 125 to 130 ° C. After reaching a clear, homogeneous melt (end of the reaction), the resulting NCO prepolymer is reacted with chain extenders or mixtures of chain extenders.

The used herein chain extenders are from the literature known.

Preferably may as chain extenders, for example, the following Compounds used are: linear, aliphatic α, ω-diols with 2 to 12 carbon atoms and water, more preferably butanediol, Hexanediol, ethoxylated hydroquinone and cyclohexanediol or mixtures it. Further chain extenders are the polyols B), which already in the preparation of NCO prepolymers used ("polyol splitting") can also be used.

Besides For the production of PU elastomers also higher functional Polyols having 3 or 4 OH groups in the molecule, such as. B. triols (eg, 1,1,1-trimethylolpropane) in minor proportions of 0 to 10% by weight, be used in relation to the chain extenders. Water can also be used as a chain extender. In the case of the use of water are preferably dispersing aids with inserted. Preferably, when using water, the so-called "polyol splitting" carried out by adding a part of the preparation of the prepolymer polyol used together with the water added to the prepolymer becomes.

Farther can the known from the prior art auxiliary and Additives, such as. As catalysts, stabilizers and emulsifiers be used in the known quantities.

Examples for catalysts are trialkylamines, peralkylated polyamines, Diazabicyclooctane, tin dioctoate, dibutyltin dilaurate, N-alkylmorpholine, Lead, zinc, calcium, magnesium octoate, the corresponding naphthenates, p-nitrophenolate, etc.

Examples for stabilizers are Broenstedt and Lewis acids, such as Hydrochloric acid, benzoyl chloride, organomineric acids, z. B. dibutyl phosphate, boron trichloride, adipic acid, Glutaric acid, succinic acid and malic acid, Citric acid etc.

Furthermore, UV protection agents, such as. For example, 2,6-dibutyl-4-methylphenol, hydrolysis, z. As carbodiimides, as well as emulsifiers, foam stabilizers, cell regulators, blowing agents, flame retardants, oxidation stabilizers and fillers are used. An overview is z. In G. Oertel, Polyurethane Handbook, 2nd edition, Carl Hanser Verlag, Munich, 1994, chap. 3.4 contain.

The PUR elastomers according to the invention are preferably foamed (cellular) or unfoamed cast elastomers.

The Cast elastomers are preferably used in the production used by technical semi-finished products. Typical applications Solid cast elastomers are, for example, hydrocyclones, Coupling elements, pump and switching membranes, doctor blade tires for Screen printing technology, roller coverings and twin-disk rotor bearings. Areas of application of cellular cast elastomers are, for example Scraper rings, decouplings, spring elements, support bearings and winding rollers. The PUR elastomers can be used as PUR moldings or Coatings, in particular used in printing technology.

The Invention will be more apparent from the following examples be explained.

Examples

Used starting compounds

• Vulkollan ^® 2000 M from Bayer Material Science AG. Polyethylene adipate, OH number (OHN) 55 succinic acid (99%) from Acros.
• Desmodur ^® 15 from Bayer MaterialScience AG. 1,5-naphthalene 1,1,1-trimethylolpropane
• Maraflex FX 980: screen printing ink from Marabu GmbH & Co.
• Maraswitch MSW 980: screen printing ink from Marabu GmbH & Co.
• Maragloss GO 073: screen printing ink from Marabu GmbH & Co.

Example 1: Polyester Synthesis

4585 g (43.25 mol) of diethylene glycol and 4610 g (39.06 mol) of succinic acid were slowly heated to 200 ° C with stirring under normal pressure and under nitrogen, wherein the resulting reaction water was distilled off. After about 5 hours, 180 mg of tin dichloride dihydrate were added and vacuum slowly applied to 15 mbar. After another 20 hours, the reaction was complete. The analysis gave the values listed in Table 1. The reaction was repeated with the starting compounds listed in Table 1, respectively. Table 1: Characterization of the polyesterpolyols example 1-1 1-2 1-3 (comparison) adipic acid X Succinic acid X X ethylene glycol X X diethylene glycol X X OH number [mg KOH / g] 57.1 57.6 55 acid number [mg KOH / g] 0.5 0.6 0.7 viscosity [mPas, 75 ° C] 1400 930 540

Example 2: Synthesis of PUR elastomers

Production of a Casting Elastomer Example 2-2:

100 Parts by weight. of the polyol of Example 1-2 were at 135 ° C heated. While stirring, 18 parts by weight were added. solid To give 1,5-naphthalene diisocyanate, the temperature at 100 ° C. plummeted. After 3 minutes, vacuum was applied to the reaction mixture to degas. The reacting melt warmed as a result the reaction after 19 minutes at 124 ° C. To this prepolymer were added 2 parts by weight. 1,4-butanediol with vigorous stirring for 30 seconds added so that no air bubbles appeared in the mixture. The responding Mixture was preheated to 116 ° C poured, demolded after about 38 minutes and the moldings at 110 ° C in a convection oven for 24 Refurbished hours. After about 1 month of storage at room temperature the mechanical properties were determined.

Other PUR elastomers were prepared as described above. The formulations and the properties of the elastomers are shown in Table 2. The indicated ratios refer to the molar ratios of the raw materials used, ie they are the quotient of the number of NCO groups of the diisocyanate to the total number of OH groups of the chain extender and the OH groups of the polyol. Table 2: Synthesis and characterization of PUR elastomers Example: 2-1 (V) 2-2 2-3 2-4 2-5 2-6 2-7 recipe: NDI [Parts by weight.] 18 18 18 18 18 18 18 Polyol 1-1 [Parts by weight.] 100 Polyol 1-2 [Parts by weight.] 100 100 100 100 100 Polyol 1-3 [Parts by weight.] 100 butanediol [Parts by weight.] 2 2 1.8 1.84 1.61 1.38 1.38 1,1,1-trimethylolpropane [Parts by weight.] 0.2 0.46 0.69 0.92 0.92 identification number 1.20 1.17 1.17 1.12 1.12 1.11 1.12 Processing: demolding [Min] 20 38 60 70 85 120 120 Mechanical properties: DIN 53505 hardness [Shore A] 86 85 80 78 73 66 64 DIN 53505 hardness [Shore D] 34 30 27 26 23 20 20 DIN 53504 Tension, 100% [MPa] 5 4.8 3.57 3.31 2.73 2.22 2.64 DIN 53504 Tension, 200% [MPa] 7 6.3 4.84 4.38 3.7 3.04 3.83 DIN 53504 Tension, 300% [MPa] 10 7.6 6.01 5.32 4.62 3.89 5.63 DIN 53504 breaking stress [MPa] 45 13.4 21.4 23.7 14.2 14.1 9.71 DIN 53504 elongation [%] 650 797 747 762 657 653 404 DIN 53515 Graves [KN / m] 30 30 18 16 12 10 8th elasticity [%] 54 45 41 38 34 30 12 DIN 53516 Abrasion (DIN) [mm ³ ] 41 51 55 78 122 170 116 DIN 53517 Compression set, 70 ° C [%] 20 30.6 25.9 23.9 17.1 13.6 6.2

table Figure 2 shows that the polyadipate polyol (polyol 1-3) based Comparative system (Example 2-1) a Shore A hardness of 86 and thus largely in terms of hardness is equal to the elastomer of 2-2. Examples 2-3 to 2-7 included 1,1,1-trimethylolpropane, as expected a waste in the hard leads.

Example 3: Determination of Swelling Behavior in screen printing inks

The determination of the swelling behavior in screen printing inks was carried out by the PUR Elasto meren from Example 2 in the form of cylindrical specimens of diameter 30 mm and thickness of 2.5 mm for different lengths of time (3, 7 and 10 days) were stored at room temperature in screen printing inks. The weight of the specimens before and after storage was determined and weight gain was calculated to give an original weight gain (in%). The results of these tests are listed in Table 3: Table 3: Swelling tests in printing inks; Weight gain of PUR elastomers after storage at room temperature example 3-1 (V) 3-2 3-3 3-4 3-5 3-6 3-7 PU elastomer 2-1 (V) 2-2 2-3 2-4 2-5 2-6 2-7 in Maraflex FX980 days 3 Weight gain [%] 76.91 61.78 42,10 39.54 45.81 59.44 66.42 7 Weight gain [%] 106.53 66.36 77.98 79.32 86,60 98.28 81.84 10 Weight gain [%] 113.71 66,99 78.73 81.04 86.79 99.43 82,95 in Maraswitch MSW980 3 Weight gain [%] 51.16 35,65 23.61 22.23 38.48 49,98 33.97 7 Weight gain [%] 73.98 45,26 49.05 53.04 56.83 66,00 51,30 10 Weight gain [%] 84.22 48.81 51.89 56.13 59.70 65.84 58.12 in Maragloss GO073 3 Weight gain [%] 33,00 13.75 11.75 11.36 12.68 15.17 -1.83 7 Weight gain [%] 46,85 18.05 21.73 20.10 22.30 26.44 1.67 10 Weight gain [%] 53.70 23.41 24.23 22.70 25.33 26.70 4.73

table 3 shows that the PUR elastomers according to the invention when stored in Maraflex FX980 compared to the comparison (Bspl. 3-1 (V)) show swelling values that are significantly better.

analog applies to the swelling experiments in Maraswitch MSW980.

at Storage in Maragloss GO073 is almost always the swelling value below 50% of the reference value.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 1694169 A [0003]
• - JP 1989119484 A [0004]

Cited non-patent literature

• - G. Oertel, Polyurethane Handbook, 2nd edition, Carl Hanser Verlag, Munich, 1994, chap. 3.4 [0028]
• - DIN 53505 [0034]
• - DIN 53505 [0034]
• - DIN 53504 [0034]
• - DIN 53504 [0034]
• - DIN 53504 [0034]
• - DIN 53504 [0034]
• - DIN 53504 [0034]
• - DIN 53515 [0034]
• - DIN 53516 [0034]
• - DIN 53517 [0034]

Claims (6)

PUR elastomers obtainable by reaction from A) 1,5-naphthalene diisocyanate and B) polysuccinate polyols with Molar masses of 500 to 5000 g / mol and average functionalities from 1.95 to 2.25 and subsequent implementation of the A) and B) obtained NCO prepolymer with C) short-chain hydroxyl groups having chain extenders with molecular weights of 62 to 450 g / mol and functionalities of 2 or 3 or water. PUR elastomers according to claim 1, characterized in that the polysuccinate polyols are from succinic acid or succinic acid derivatives and diols having molecular weights of 62 to 300 Da and optionally short-chain polyols with functionalities of 3 or 4, preferably glycerol and 1,1,1-trimethylolpropane available are. PUR elastomers according to claim 2, characterized in that that in addition to the succinic acid max. 5% by weight of other acids from the group consisting of aliphatic, araliphatic or aromatic dicarboxylic acids in the synthesis of Polysuccinatpolyole are present. PUR elastomers according to claim 1, characterized that as a chain extender (C) compounds from the group consisting of butanediol, hexanediol, ethoxylated hydroquinone and Cyclohexanediol or mixtures thereof can be used. Process for the preparation of PU elastomers Base A) 1,5-naphthalene diisocyanate (NDI), B) polysuccinate polyols with molecular weights of 500-5000 Da and average functionalities from 1.95 to 2.25, C) hydroxyl-containing chain extenders with molecular weights of 62 to 450 Da and functionalities of 2 to 3 or water, where components A) and B) to NCO prepolymers be reacted with an NCO content of 2.5 to 6 wt .-%, and then the NCO prepolymers formed with chain extenders or water C) while maintaining a figure of 1.04 to 1.25 be converted to PUR elastomers. Use of the PUR elastomers according to the claims 1 to 4 as PUR moldings or coatings.