WO2006024544A1

WO2006024544A1 - Modified aminotriazine resin and method for the production thereof

Info

Publication number: WO2006024544A1
Application number: PCT/EP2005/009513
Authority: WO
Inventors: Christian FÜRST; Markus Machherndl; Frank SCHRÖDER; Johannes Fellner
Original assignee: Ami Agrolinz Melamine International Gmbh
Priority date: 2004-09-03
Filing date: 2005-09-01
Publication date: 2006-03-09
Also published as: DE102004043213A1; CA2577944A1; EP1791878A1

Abstract

The invention relates to a modified aminotriazine resin, particularly melamine formaldehyde resin, which has a high reactivity and can be obtained by reacting a modified aminotriazine resin melt with at least one aminotriazine, particularly melamine, which is in the form of a solid and/or a suspension, at a temperature ranging from 130 to 250 °C and with a dwell time of 30 to 600 s. This makes it possible to produce aminotriazine resins that have an increased reactivity during molar mass build-up inside the extruder and during the final curing, and even in the event of high aminotriazine contents, are stabile and capable of being stored.

Description

Modified aminotriazine resin and a process for its preparation

The invention relates to a modified aminotriazine resin according to claim 1, a process for its preparation according to claim 10 and its use according to claim 14.

Aminotriazine resins are condensation products of an aminotriazine with a carbonyl compound. The most technically important Aminotriazinharze are melamine-formaldehyde resins.

Aminotriazine resins in which the primary Aminotriazinkondensationsprodukte are modified, for example, with alcohols or polyols

Ether groups in their structure; They are referred to as modified Aminotriazinharze. From WO 03/046053 A1 or WO 03/106558 A1, for example, modified aminotriazine resins are known which have a sufficiently high melt viscosity so that they can be processed by thermoplastic processes such as, for example, extrusion or injection molding.

Such resins are usually obtained by a process in which a modified aminotriazine resin is prepared in a liquid form, which is then concentrated to a resin melt, and the resin melt is then reactively reacted at elevated temperature in extruders, kneaders or the like.

The thermoplastically processable modified aminotriazine resins obtained in this way have several disadvantages.

They show a relatively low reactivity in the reaction in the extruder, in which the highest possible molar mass of the resins should take place. To achieve a molecular weight structure with sufficient speed, are in the known resins high extrusion temperatures necessary. High extrusion temperatures are disadvantageous because the extrusion process is difficult to control and there is a risk of spontaneous curing of the resins in the extruder.

Another disadvantage of the known aminotriazine resins is their slow hardening in the final shaping. High cure temperatures, long residence times, and relatively large amounts of cure catalysts are needed to effect final cure.

Furthermore, hitherto modified aminotriazine resin solutions having a molar ratio of formaldehyde: aminotriazine of at least 2: 1 can be prepared stably at room temperature. Higher Aminotriazinanteile are not or only by very complicated reaction can be realized. When cooling to room temperature, the product or aminotriazine usually precipitates out of the resin solutions, which makes further processing very difficult. The higher the formaldehyde content, the more unwanted emissions of methanol and formaldehyde occur both during processing of the resins and from the final product. A further disadvantage is the easy flammability of the resins, which is also higher, the higher the formaldehyde content and the degree of modification of the resins.

Object of the present invention was therefore to find an aminotriazine resin which does not have the disadvantages mentioned.

This object is achieved by an aminotriazine resin according to claim 1.

The present invention is a modified aminotriazine resin, in particular melamine-formaldehyde resin, which is obtainable by reacting a modified Aminotriazinharzschmelze with at least one in the form of a Solid and / or a suspension present Aminotriazin, in particular melamine, at a temperature of 130 to 250 ⁰ C and a residence time of 30 to 600 s.

The advantage of the aminotriazine resin according to the invention is that it shows an increased reactivity in the molecular weight build-up in the extruder and in the final curing. In this way, even in the extruder, a large part of the unwanted fission products can be removed, which are otherwise released only during processing and in the final product. Furthermore, the aminotriazine resins according to the invention are stable even with high aminotriazine contents and can be prepared in a simple manner.

Suitable aminotriazines for the preparation of the modified Aminotriazinharzschmelze are, for example, melamine, guanamines, Oxoaminotriazine such as ammine or ammelide or substituted melamines. Preferably, melamine is used. For the preparation of the modified Aminotriazinharzschmelze certain amounts of urea and / or dicyandiamide may be used in addition to the aminotriazine.

Suitable carbonyl compounds for the preparation of the modified aminotriazine resin melt are, for example, formaldehyde, acetaldehyde, isobutyraldehyde, acetone, methyl ethyl ketone, glyoxylic acid, methyl glyoxylate hemiacetal, glyoxal, glutaric dialdehyde or diethyl ketone. Preferably, the carbonyl compound used is formaldehyde.

In the modified aminotriazine resin, the primary condensation products of carbonyl compound and aminotriazine are partially or completely etherified with C 1 -C 4 -alcohols. The partially or fully etherified condensation products can be partially or completely trans-etherified in a further reaction step, wherein the transetherification preferably with aliphatic C ₄ -C ₈ alcohols or aromatic Alcohols, diols or polyols or mixtures thereof takes place.

A modified aminotriazine resin in the context of the present invention is also one which, in addition to or instead of the etherification and / or transetherification with alcohols, diols and polyols, for example by condensing or subsequent addition of other conventional modifiers such as caprolactam, sulfites, sulfonamides, carbamates , Salts of maleic or fumaric acid monoamides,

Epoxides, Bisepoxiden or isocyanates is obtained. Furthermore, fillers and / or reinforcing fibers, other polymers and stabilizers, UV absorbers and / or auxiliaries may also be present in the modified aminotriazine resin.

The modified aminotriazine resin melt is particularly preferably formed from a condensation product of the components melamine and formaldehyde. It usually has a molar ratio

Carbonyl compound: Aminotriazine from 2: 1 to 3.5: 1, whereby higher carbonyl contents up to 6: 1 are possible.

Advantageously, the reaction of the modified Aminotriazinharzschmelze with at least one Aminotriazin at a temperature of 190 to 250 ⁰ C instead.

This ensures that the dosed aminotriazine reacts particularly rapidly reactively with the Aminotriazinharzschmelze.

The necessary amount of aminotriazine is from several

Dependent on parameters:

1) Which carbonyl: aminotriazine ratio should be in

End product and 2) which carbonyl: aminotriazine ratio had the

Output Aminotriazinharzschmelze. This gives (at a predetermined throughput) how much aminotriazine has to be added. (Addition of the aminotriazine shifts the carbonyl: aminotriazine ratio, ie, lowers it).

The amount of aminotriazine dosed is preferably selected such that in the resulting aminotriazine resin the molar ratio of the sum of the carbonyl compounds to the sum of the aminotriazines is smaller by 0.1 to 1.5 units than the molar ratio of the sum of the carbonyl compounds to

Sum of aminotriazines in the modified aminotriazine resin melt.

Particularly preferred in the resulting aminotriazine resin is the molar ratio of the sum of the carbonyl compounds to

Sum of the aminotriazines by 0.3 to 1.0 units smaller than the molar ratio of the sum of the carbonyl compounds to the sum of aminotriazines in the modified aminotriazine resin melt. Aminotriazine resins, which have this molar ratio, are easy to process and the reaction is technically easy to control. This formulation defines the amount of aminotriazine dosed.

Preferably, in the modified aminotriazine resin, the molar ratio of carbonyl'.minotriazine is less than 2: 1, more preferably less than 1.6: 1.

Modified aminotriazine resins containing such high aminotriazine are conventionally not yet obtainable in stable form. They show particularly low emissions, favorable flame retardant properties and a very fast curing rate.

The invention further provides a process for the preparation of a modified aminotriazine resin, which comprises preparing a modified aminotriazine resin melt, the modified aminotriazine resin ^{melt is} subsequently reacted reactively in at least one extruder or kneader, wherein at least one aminotriazine, in particular melamine, is metered in as solid and / or as suspension before and / or during the reactive reaction to the modified aminotriazine resin melt, whereupon the modified aminotriazine resin is discharged ,

The modified aminoplast resin melt is prepared, for example, as described in WO 03/046053 or in WO 03/106558 or by concentrating modified aminoplast resin solutions in thin-film evaporators in accordance with WO 04/056900 A1.

The aminotriazine added to the aminotriazine resin melt surprisingly reacts with the

Aminotriazine resin melt around and it is obtained a clear resin strand, which can be processed in a conventional manner.

The dosed aminotriazine acts as a crosslinking center, as a flame retardant component and also as a scavenger for the carbonyl compounds used. Furthermore, volatile reactive cleavage products are released in the reactive incorporation of the aminotriazine, so that the modified aminotriazine resins according to the invention have lower emissions than the modified aminotriazine resins which can be prepared by conventional processes.

Advantageously, the solid aminotriazine is finely divided or formed as a powder.

The metered addition of at least one aminotriazine preferably takes place in at least one extruder or kneader. As a result, a good distribution and incorporation of the dosed aminotriazine is achieved in the Aminotriazinharzschmelze.

As extruder, for example, a twin-screw extruder is used. It is also possible to operate two extruders or kneaders in series.

The dosed aminotriazine can be added gravimetrically in the form of a solid. Preferably, the amino triazine is added as a suspension.

For example, water, alcohols, such as butanol or methanol, diols or polyols, such as, for example, simulsols, caprolactone derivatives, poly-, oligester-ester polyols, trimethylolpropane or mixtures of these components, can be used as suspending agents. As further suspending agents, higher-viscosity, concentrated resin solutions are possible. In order to obtain a suspension capable of pumping and metering, the suspension can be stirred and heated. The solids content of the suspension is about 30 to 90% by weight, preferably about 40 to 80% by weight.

It is particularly advantageous, as suspension agent, the modified Aminotriazinharzschmelze and / or at least one

To use part of the transetherifying and / or modifying agents used for the modification.

Advantage in the addition of aminotriazine as a suspension is the better meterability compared to the addition in the form of a solid.

Suitable aminotriazines for the addition to the modified aminotriazine resin melt are, for example, melamine, oxoaminotriazines such as, for example, ammeline or ammelide, guanamines or substituted melamines. Preferably, at least one dosed aminotriazine is melamine. In a preferred embodiment, a mixture of different aminotriazines is added. This makes it possible to produce different resin types with advantageous properties. The higher the proportion of oxoaminotriazines is chosen, the greater the curing rate of the resulting resin.

It is further preferred that, in addition to or instead of a mixture of different aminotriazines, a mixture of at least one aminotriazine and a compound present in encapsulated form is metered in. The compound present in encapsulated form contains phosphorus and / or nitrogen and / or boron in chemically bound form. The compound is, for example, an inorganic or organic phosphorus, nitrogen and / or boron compound and preferably acts both flame-retardant and proton-releasing. For example, serve

Ammonium polyphosphate, melamine polyphosphate, phosphoric acid esters and phosphonic acid esters based on the reaction of phosphorus pentoxide or phosphorus trioxide with pentaerythritol or dipentaerythritol, and their ammonium and melamine salts as an encapsulated compound, wherein a modified aminoplast resin can be used as the capsule wall material. As a result, modified aminotriazine resins having an even better flame retardancy, an even higher reactivity and curing rate are obtainable, since the encapsulated compound also has an effect as a curing catalyst in addition to its flame retardant.

After the reactive reaction of modified with at least one aminotriazine modified

Aminotriazine resin melt in the extruder or kneader, the resulting modified aminotriazine resin is formulated, for example, granulated and discharged. As granulators are usually strand granulators, roll granulators, Heißabschlaggranulatoren or Pastilliervorrichtungen use. The modified aminotriazine resins obtainable by the process of the present invention can be used in a variety of ways.

They are for example used as injection molding resins. It is also possible to process the aminotriazine resins according to the invention with a carrier material to form a composite material. As support materials, for example, fibers, tile, fabric, wood and / or polymers can be used.

Furthermore, the aminotriazine resins of the invention can be used for the production of moldings such as pipes, plates, profiles or fibers.

The modified aminotriazine resins according to the invention have an increased reactivity with respect to molar mass composition compared with the conventional modified aminotriazine resins having the same carbonyl: aminotriazine molar ratio. The dosed aminotriazine acts as a crosslinking center and accelerates crosslinking both in the extruder and in the final curing. Accordingly, in certain applications, the addition of a separate curing catalyst can be dispensed with.

In the following the invention will be explained by means of examples.

1 Preparation of the modified aminotriazine resin of high reactivity

Modified aminotriazine resin melts were prepared as described in WO 04/056900 A1. In Table 1, the starting composition is the modified

Aminotriazine resin melts, the amount of aminotriazine added in the extruder, the amount of capsules added and to polyol as a modifying or suspending agent and the composition of the modified aminotriazine resins of the invention as the final product in granular form after the reactive reaction. As the aminotriazine added in the extruder, melamine or oxoaminotriazines were used.

Table 1 shows how much% by weight of melamine powder was added to the usual particle size distribution or how much% by weight of melamine was added in which amount of polyol was suspended.

The experimental parameters for the reactive conversion of Aminotriazinharzschmelzen and the properties of the resulting modified Aminotriazinharze high reactivity are shown in Table 2.

In Examples Vl, 2 and 3, modified aminotriazine resins having a formaldehyde: aminotriazine ratio of 2: 1 were prepared. In comparative example VI, no aminotriazine was added during the extrusion. In Examples 2 and 3, the formaldehyde: aminotriazine ratio of 2: 1 in the final product was achieved by reactive reaction of a modified aminotriazine resin melt with a formaldehyde: melamine ratio of 2.5: 1 with melamine or oxoaminotriazines.

In Examples V4 and 5, modified aminotriazine resins having a formaldehyde: melamine ratio of 2.5: 1 were prepared. In Comparative Example C4, no aminotriazine was added during the extrusion. In Example 5, the formaldehyde: melamine ratio of 2.5: 1 in the final product was achieved by reactive reaction of a modified aminotriazine resin melt with a formaldehyde: melamine ratio of 3: 1 with melamine. In Examples V8 and 9, modified aminotriazine resins having a formaldehyde: melamine ratio of 3: 1 and containing the transesterification agent Sirαulsol BPPE were prepared. In Comparative Example C8, no aminotriazine was added during extrusion. At the

Example 9 was the formaldehyde: melamine ratio of 3: 1 in the final product by reactive reaction of a modified Aminotriazinharzschmelze with a formaldehyde: melamine ratio of 3.5: 1 with melamine, suspended in Simulsol BPPE achieved.

In Example 6, a modified aminotriazine resin having the very low formaldehyde: melamine ratio of 1.5: 1 was prepared. It was obtained by reactive reaction of a modified Aminotriazinharzschmelze with a

Formaldehyde: Melamine ratio of 2: 1 with melamine.

In Example 7, a modified aminotriazine resin having a formaldehyde: melamine ratio of 1.71: 1 containing the encapsulated compound Exolit AP462 was prepared. It was obtained by reactive reaction of a modified aminotriazine resin melt having a formaldehyde-melamine ratio of 2: 1 with melamine and exolite AP462.

The extrusion was carried out under degassing _vacuum Pe _xtr? an average temperature of the cylinders 2-8 of the extruder of T02-8, a melt temperature of T _Mas se and a screw _speed n _Extr - The feed into the extruder is ^m Εxtr-Einr the output of the extruder is m ' _E χtr-Au _s specified.

The extruded strand of the modified aminotriazine resin of the invention was cooled and granulated after extrusion. T _g represents the glass transition temperature of the granulate, the isothermal η melt viscosity measured at 130 ⁰ C. Table 2 also shows the content of methanol in% by weight, based on the total weight of the extrudates. This is determined by acidic total hydrolysis of the methoxy groups of the resin by gas chromatography. The methanol content corresponds to the potentially releasable methanol, which is why the lowest possible methanol content in the resin is desired.

The curing time in s given in Table 2 denotes the time required to reach 10 Pa * s at 180 ^° C. (Dynamic Mechanical Analysis DMA).

From Tables 1 and 2 it can be seen that those modified Aminotriazinharze which were prepared by reactive reaction with the addition of aminotriazines, in comparison to the resins with the same

Formaldehyde: Aminotriazine ratio, which were prepared at similar and sometimes sharper extrusion conditions, but without the addition of aminotriazines in a conventional manner, are more reactive, potentially lower emissions and higher viscosity. It can also be seen that with the addition of oxoaminotriazines and encapsulated compounds such as Exolit AP462, an additional improvement in the stated properties can be achieved.

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Table 1

¹ M ... melamine F ... formaldehyde OAT ... oxoaminotriazines (mixture of 73% ammeline, 25% ammelide, 2% cyanuric acid) ² Simulsol BPPE

³ Exolit AP462

⁴ melamine suspended in polyol added

Table 2

'Determination of curing time, time to reach 10 Pa * s at 180 ° C

2 Preparation of a Reinharzplatte from the modified Aminotriazinharz

From the modified aminotriazine resins of the experiments Vl, 2, 6, 7, V8, 9 prepared in 1 a press plate with the dimensions 100 × 100 × 3 mm was produced.

The tool for this was a laminate press. The granulate was milled and the powder is then heated in the 100 ⁰ C

Filled stainless steel mold and melted for about 8 min at this temperature.

Subsequently, the pressing tool was heated to 180 ⁰ C, for

Placed in the 180 ⁰ C hot press for 30 min and pressed at 80 bar. After that took place for a period of about 15 minutes the

Cooling of the specimen in the press to 70 ⁰ C.

The pure resin plate was removed at 70 ° C from the mold. Test rods were produced from this pure resin plate with which mechanical tests and fire tests were carried out in tests A to F.

The fire test UL-94 is a test for determining the flammability of materials. The classification is based on the fire classes V-O, V-I, V-2, n.b .. V-O is the highest and thus best fire class, that is, the fire behavior meets all test criteria, n.b. does not pass, that is, the fire behavior is bad. The UL-94 test is performed according to ASTM 2863, vertical.

Furthermore, the time required for curing, the emissions during processing and the

Volume contraction determined as a measure of the shrinkage of the resin during curing.

The properties of the pure resin plate are shown in Table 3. With respect to the fire tests, Table 3 shows that the modified aminotriazine resins according to the invention have an improved fire behavior compared to the conventional resins. In tests A and E, which were carried out with conventional comparative resins to which no aminotriazine had been added, the fire test could not be passed. In tests B, C and F, which were carried out with the aminotriazine resins according to the invention, the fire classes VI and V-2 were achieved. In experiment D, carried out with a resin according to the invention which additionally contains the encapsulated compound AP462, the best fire class VO could be achieved.

It is further apparent from Table 3 that the reactive reaction of resin melts with aminotriazines does not result in deterioration of mechanical properties such as tensile strength and tensile elongation compared to the conventional modified aminotriazine resins.

The reactivity of the modified aminotriazine resins according to the invention is markedly increased in comparison with the conventional resins having the same formaldehyde: melamine ratio. This can be seen from a significantly shorter curing time of the resins according to the invention.

The modified aminotriazine resins according to the invention exhibit lower emissions than the comparable conventional resins.

Even with the volume contraction as a measure of the shrinkage of the resin during curing, significantly lower values result for the aminotriazine resins according to the invention than in the conventional aminotriazine resins. Particularly low values can be observed in experiment D, carried out with an aminotriazine resin containing the encapsulated compound Exolit AP462. 3 Production of natural fiber composites

The modified aminotriazine resin of the experiments Vl, 2, 6, 7, V8, 9 from 1 according to the invention was sprinkled with a powder spreader onto a flax fiber fleece having a basis weight of 300-350 g / m ² , whereby a resin coverage of about 30% of the total weight was achieved , The powdered nonwoven fabric was then precondensed in an IR-FeId at 190 ⁰ C for 2 min, then molds were punched out with 300 x 200 mm. 6 layers of powder-coated webs were then placed one above the other with the powder-coated side up and down this pre-condensed fiber composite in a heated to 18O ⁰ C evacuable upper piston press. After a preheating time of 30 seconds, compression was effected in the first pressing stage for 20 seconds to 40OKN, at the same time the vacuum was set to 200 mbar absolute pressure. Thereafter, it was deaerated for 20 sec under vacuum. In the second pressing step, the fiber composite was pressed to the degree of curing of 95%, measured by means of ultrasound. The cured composite material was removed at 180 ^C C hot.

With the composite materials thus obtained, the same tests were carried out in experiments Al to Fl as with the pure resin plate from 2. The properties of the composites produced are shown in Table 4.

All the advantages of the modified aminotriazine resins according to the invention in comparison with the conventional resins having the same formaldehyde-aminotriazine ratio can also be observed with the fiber composites prepared from the resins.

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Table 3

'M ... Melamine F ... Formaldehyde K ... Capsules (Exolit AP 462) P ... Polyol (Sünulsol BPPE)

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Table 4

⁷ M ... Melamine F ... Formaldehyde K ... Capsules (Exolit AP 462) P ... Polyol (Simulsol BPPE)

Claims

claims

1. Modified aminotriazine resin, in particular melamine

Formaldehyde resin,

available through

Reaction of a modified Aminotriazinharzschmelze with at least one present in the form of a solid and / or a suspension Aminotriazin, especially melamine.

2. Modified aminotriazine resin according to claim 1, characterized in that the solid is used in small parts or in powder form.

3. Modified aminotriazine according to claim 1 or 2, characterized in that the reaction is carried out at a temperature of 130 to 250 ⁰ C.

4. Modified aminotriazine resin according to at least one of the preceding claims, characterized in that the reaction takes place at 190 to 250 ⁰ C.

5. Modified aminotriazine resin according to at least one of the preceding claims, characterized in that the reaction has a residence time of 30 to 600 s.

6. Modified aminotriazine resin according to at least one of the preceding claims, characterized in that in the aminotriazine resin, the molar ratio of the sum of the carbonyl compounds to the sum of aminotriazines by 0.1 to 1.5 units is less than the molar ratio of the sum of the carbonyl compounds to the sum of Aminotriazines in the modified Aminotriazinharzschmelze.

7. A modified aminotriazine resin according to claim 6, characterized in that in the arαinotriazine resin, the molar ratio is smaller by 0.3 to 1.0 units than the molar ratio in the modified aminotriazine resin melt.

8. Modified aminotriazine resin according to at least one of the preceding claims, characterized in that the molar ratio of carbonyl: aminotriazine in the aminotriazine resin is less than 2: 1.

9. A modified aminotriazine resin according to at least one of the preceding claims, characterized in that the molar ratio of carbonyl: aminotriazine in the aminotriazine resin is less than 1.6: 1.

10. A process for the preparation of a modified aminotriazine resin,

characterized in that

a) a modified aminotriazine resin melt is produced,

b) the modified aminotriazine resin melt is then reactively reacted in at least one extruder or kneader,

c) wherein before and / or during the reactive reaction to the modified aminotriazine resin melt at least one aminotriazine, in particular melamine, is added as a solid and / or as a suspension,

d) whereupon the modified aminotriazine resin is carried along.

11. The method according to claim 10, characterized in that the metered addition of at least one aminotriazine takes place in at least one extruder or kneader.

12. The method according to any one of claims 10 or 11, characterized in that at least one aminotriazine is added as a suspension, wherein as a suspension agent, the modified Aminotriazinharzschmelze and / or at least one

Part of the modification of the

Aminotriazinharzschmelze used Umetherungs- and / or modifier serves.

13. The method according to at least one of claims 10 to 12, characterized in that a mixture of different • aminotriazines and / or a mixture of at least one aminotriazine and a compound present in encapsulated form are metered.

14. Use of a modified aminotriazine resin as an injection molding resin, for the production of composite materials or of molded parts.