DE2745951A1 - REACTIVE CATALYST FOR THE POLYCONDENSATION OF UREA-FORMALDEHYDE RESINS AND THEIR USE IN A PROCESS FOR THE MANUFACTURE OF CHIPBOARD - Google Patents

Description

MÜLLER-BORE DEUFEL SCHÖN HEHTSL

PATENT LAWYERS

DR. WOLFGANG MÜLLER-BORE (PATENT ADVOCATE FROM 1927-1975) DR. PAUL DEUFEL. DIPL.-CHEM. DR. ALFRED SCHÖN. DIPL.-CHEM. WERNER HERTEL. DIPL.-PHYS.

2nd OCT.

D / Hn / de - T 1396

Teukros AG, Sternengasse 20, CH 4010 Basel / Switzerland

Reactive catalyst for the polycondensation of urea-formaldehyde resins and its use in one Process for the production of chipboard

809815/0914

Description

The invention relates to a reactive catalyst which contains or consists of a mixture of organic and inorganic components, their addition to urea-formaldehyde resins, used to bond water-permeable cellulose particles together, the use of allows lower amounts of resin solids while increasing production rates without any loss of bond strength.

The catalyst of the present invention mainly consists of an organic and an inorganic component. The organic component is a concentrated one Solution of formaldehyde with urea (this solution of formaldehyde with urea consists of the monomers or from a non-resinous condensation product of these monomers), while the inorganic component is an alkali metal halide.

The rate of curing or speed becomes at high The temperature is increased to such a level that it can never be achieved by simply adding acid-hardening catalysts can be. The addition of acid-hardening catalysts increases the hardening rate or speed increased, but then a value is reached at which a further increase leads to a deterioration in the properties of the bound material leads.

In addition, the addition of the known catalysts in

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higher amounts allow the polycondensation to be carried out even at room temperature (despite the addition of retarders, such as Ammonia or hexamethylenetetramine). This will reduce the shelf life of the glue at room temperature, leading to precure prior to introduction of the mat into the press and leads to the known disadvantages of such a phenomenon.

However, by adding the catalyst according to the invention the curing rates even further increased and then the pressing times can be reduced without any deterioration in the properties of the bound material occurs. The addition of the catalyst is only effective at high temperatures. He therefore increases

essentially the polycondensation rates or speeds of the resin at the temperature of the press, without increasing it at all at room temperature, thereby avoiding any pre-hardening problems. The inventive Catalyst binds to the resin itself and becomes part of it.

The combination of an organic and an inorganic component in the catalyst according to the invention shows a synergistic behavior. If the individual components are added to the resin alone, they lead to certain Increase in the curing rate or speed, however, when added in combination, they result in an increase greater than the sum of the results obtained when each component is separated is added.

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The halide salt can be any soluble halide of an alkali metal. With the organic one Material can be a non-resinous condensate of urea with formaldehyde. Preferably will also a surface-active agent in small amounts, for example 0.1 to 2 Ti, added to the catalyst, to improve the resin dispersion.

The catalyst according to the invention (calculated as a solids content of 100%) can be added in various proportions, in particular in an amount from 1 to 30% of the resin solids used. The most important aspect of the present invention is the fact that the catalyst of the present invention can replace part of the resin without deteriorating the properties of the end product. This is not achieved by adding the catalyst in amounts equal to the amount of the replaced resin, but by adding the catalyst in amounts of 50 to 70% of the amount of the replaced resin (the calculations are based on% by weight) and that all products consist of 100 "L solids) /

Due to its synergistic behavior, the catalyst according to the invention can replace the resin in amounts up to twice its own weight. The above-mentioned property of this catalyst is evident with an addition of up to 20% of the weight of the resin, which corresponds to a replacement of up to 40% of the weight of the resin used. When it is added in smaller amounts , e.g. 3 to 10% , there is a considerable improvement in the properties of the end product. If he is in higher amounts of

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For example, if up to 30% is added, no difference can be observed with regard to the properties of the end product, however, the curing rates or velocities increase considerably and resin is saved.

The bond is brought about by curing the resin at elevated temperatures and pressures according to known methods Procedure. The catalyst can be used in all types of products that use urea-formaldehyde resins be used to bind lignocellulose products, regardless of whether they are wood particles for the production of chipboard using flat presses or calenders or around wood veneers, such as z. B. in plywood production. The quality of the boards or panels produced was checked weekly controlled over a period of 6 months and no deterioration in properties was observed. this shows that no polymer degradation occurs and that the aging properties of the boards or panels are comparable to those that have been produced in the normal way.

The previously known substitutes for replacing the resin did not allow the same known manufacturing processes to be retained at higher replacement quantities and they also did not lead to a simultaneous increase in the production speed. The known substitutes are in particular to halide salts without a mixture of a halide salt and the urea and formaldehyde additives is used.

The addition of the halide salt alone enables the replacement

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part of the resin has the following limitations in comparison to the reactive catalyst according to the invention:

1.) the production speed is not increased, im In the case of higher replacement quantities, it is actually reduced, since the substitutes act as retardants rather than catalysts because of the high amount of water present; 2.) the replacement is possible in ratios of 1: 1, while in the case of the reactive catalyst according to the invention Ratios of up to 1: 2 are possible; 3.) higher replacement quantities are obtained by spraying separately of the wood with the halide salt solution, subsequent drying and subsequent spraying of the adhesive. in the Case of the reactive catalyst according to the invention higher replacement amounts are possible without the reactive catalyst being sprayed on separately and then dried must become. The reactive catalyst is added to the resin solution and this solution is used to spray the wood pulp used in one stage by methods known per se.

The reactive catalyst according to the invention still offers another benefit. Because of the lower amount of resin used and because of the improved performance achieved the amount of free formaldehyde in the manufacture of panels and boards is considerably reduced and the obtained boards (panels) are almost odorless.

The invention is illustrated in more detail by the following examples, but without being limited to it.

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example 1

A constant amount of urea-formaldehyde resin (BASF 235) was under controlled temperature and pressure conditions reacted with the catalyst of the invention, the The catalyst varied as a function of the proportions of the constituents forming the catalyst solution. The erf A suitable catalyst was not used alone, but in addition used for the usual, known catalyst, which usually consists of ammonium chloride, hexamethylenetetramine contains or not.

The following Table I shows the synergistic effect of the catalyst solution from the organic and inorganic Components clearly set out.

Sample 1, which is to be regarded as a blank sample, and the sample according to the invention Did not contain catalyst solution, but only contained the known ammonium chloride as a catalyst, had a gel time of 90 seconds at 100 C;

sample 2 also contained, apart from ammonium chloride pine certain amount of urea-formaldehyde and she wi »s a slightly increased catalytic effect with a gel time at 100 C for 85 seconds;

Sample 3 contained, apart from ammonium chloride, also a certain amount of sodium chloride, but no urea-formaldehyde _} and it had a slightly increased catalytic effect at 100 ° C. with a gal time of 80 seconds;

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Sample 4 contained, apart from the ammonium chloride, a mixture of urea-formaldehyde and sodium chloride, the total amount of gas in the mixture added being equal to the amount
the E inci added in samples 2 and 3; ! components was. Samples 4, 5 and 6 showed an increased catalytic effect due to the synergistic behavior of the components used and the ones obtained
60, 35 or 28 seconds.

components and the gel times obtained at 100.degree

The difference between the samples 4, ^r> and 6 was a consequence of the different proportions of the organic component used in comparison to d ^ r inorganic component of Katalysatorlösiing. It was found that the
Sample 6, which has the higher amount of organic material
contained, also exhibited the greater catalytic effect.

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Table I Components in parts by weight

Urea-formaldehyde resin (with a solids content

of 65%)

water

Catalyst solution ammonium chloride (20% solution in water) Hexamethylenetetramine (20% solution in water)

<*> Gel time in seconds at 100 ° C ο CD OO ~~ * Kempen? .N ton of the catalyst or solution

cn '' ■ ■

^ Urea (100%) - 5.35 - 5.35 10.70 16.05

2 Formaldehyde (100%) - 2.75 - 2.75 5.50 8.25

"Sodium Chloride (100%) - - 20.0 20.0 20.0 20.0

surfactant (10% solution in water) - 1.0 1.0 1.0 1.0 1.0

§ water - 90.9 79.0 70.9 c2.8 54.7

■ g total - 100.0 100.0 100.0 100.0 100.0

2 3 rehearse 5 6th 1 140 140 4th 140 140 140 10 10 140 10 10 70 60 60 10 60 60 - 12th 12th 60 12th 12th 12th 8th 8th 12th 8th 8th 8th 85 80 8th 35 28 90 Weight 60 Parts

Example 2

This example explains the advantages of chipboard * Production were achieved when the catalyst according to the invention was stretched to the mixture.

The following explains three cases in which the same total amount of solution was used. There were differences in relation to the different properties of the various components of the solution used, as in the following Table II given. It should be noted that the column A relates to the spraying of fine wood flour, which in turn used to make the outer surface of the chipboard, solution used refers while the column B refers to the spraying of wood chips, which in turn were used to make the core of the chipboard, the solution used.

In this example, the chipboard was made according to the bison system, d. H. with continuous layer formation under controlled conditions that are kept constant for all cases explained have been produced:

Moisture of the mat before pressing 10.5 - 0.5%, press temperature 210 ° C

Pressure 35 kg / cm ²

The qualities of the chipboard produced in this way did not show any noticeable differences in any of the three cases (see the results in Table II).

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In the three cases according to the example according to the invention The various solutions produced led to a reduction in the pressing time, as indicated below:

Sample 1: 9.25 sec. per ram of the non-sanded (sanded) Chipboard,

Sample 2: 8.00 sec. per mm of the non-sanded or sanded Chipboard,

Sample 3; 7.00 sec. per mm of the non-sanded chipboard.

The third sample, which has the largest amount of organic component in comparison to the inorganic component, showed the best results.

The above example shows that by using the catalyst according to the invention it is possible to shorten the pressing time in the production of particle board and that at the same time it is possible to reduce the use of resin by an amount of up to 30 J _{0 when using this catalyst} , up to 16.90% (sample 2) or up to 21% (sample 3).

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Table II Components in parts by weight

Urine tof f fortnaldehyde resin (with 65% solids content)

Ammonium chloride (20% solution in water) Water Amuionicil: with 25 trees Catalyst solution

2 Total 170.0 240.0 170.0 240.0 170.0 240.0

Components of the catalyst solution

^ Urea (100%) - - 5.35 5.35 10.70 10.70 V.

g formaldehyde (100%) - ---------

^ Sodium Chloride (100 %)

Surfactant (10% solution in water) -water

A- 1 B. 70 A- rehearse A. ³ T * 0 , 0 - , 0 2 « A. B. 200 , 0 58 B. 70.0 140.0 100, 5 8th , 0 1 , 5 140.0 - 8.0 - 5 31 , 0 40 , 5 8.0 58.5 20.0 68, 1 , 0 20.0 1.5 2.0 1, - 2.0 40.0 70.0 - 70.0

5.35 5.35 10.70 10.70 2.75 2.75 5.50 5.50 20.0 20.0 20.0 20.0 1.0 1.0 1.0 1.0 70.9 70.9 62.8 62.8

Total amount - - 100.0 100.0 100.0 100.0

properties

Density (kg / m ³ ) 660 640 625

Thickness in imm 16.2 16.0 16.1

Modulus of elasticity L 26 000 23 200 24 000

g tensile strength in kg / cm ² 5.0 4.5 4.2

^ Bond strength in kp / cm ² 250 230 225

^ Water absorption capacity in% after immersion for 24 hours 40 45 52

Q Percentage of increase in swelling after 24 hours

<d immersion 13 15 20

cn co cn

Example 3

This example illustrates the increase in the rate of particleboard manufacture achieved when the catalyst of the invention of the mixture (i.e. a Mixture of sodium chloride and urea-formaldehyde monomers) is added compared to the rate that would be used with the simple addition of sodium chloride (without the urea-formaldehyde monomers) is obtained.

The results obtained are given in the following Table III, in which the sample!, Apart from the usual Additives that are added to the resin mixture for the manufacture of chipboard, only contained sodium chloride and therefore a gel time of 80 sec. had, while sample 2 had the same additives as sample 1, but in addition still contained urea and formaldehyde monomers as well as the same amount of sodium chloride and therefore a gel time from 28 sec. would have.

The under the same conditions when using a bison plant obtained for both samples according to the invention Chipboard gave a production rate of 9 seconds. per mm in the case of sample 1 and of 7 sec. per mm in the case of sample 2. The mechanical properties achieved in accordance with DIN 52 360 to 52 365 were in both Cases the same.

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Table III

Urea-formaldehyde resin (solids content 65%)

water

Ammonium chloride (20% solution in water)

Hexamethylenetetramine Sodium Chloride (100%) Urea (100%) Formaldehyde (100%)

total quantity

Gel time in sec.

Eating time in seconds per mm

Thickness of the non-sanded chipboard

rehearse

1 12th - 2 140 - 140 58 230.00 43.42 12th 80 12th 8th 8th 12th 9.63 4.95 230.00 28

properties

Density (kg / m ³ ) Thickness in mm

Young's modulus L

2 tensile strength kp / cm

2 Flexural strength in kp / cm

% Water absorption after 24 hours Immersion

Swelling in% increase after 24 hours Immersion

45 60 13.4 14.9

Example 4

This example illustrates the increased substitution of the

Addition of the catalyst according to the invention obtained urinary

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substance-formaldehyde resin compared to the lower substitution, which was achieved using only sodium chloride without adding urea and formaldehyde monomers, chipboards were obtained which had equivalent mechanical properties in both cases.

This example illustrates in particular the case where the substitution in the case of sodium chloride with respect to the Resin was 1: 1, while in the case of the mixture of sodium chloride with urea and formaldehyde, the resin substitution Was 1: 2. A supply of wood chips was made after pulverizing with the corresponding ones given in Table IV below Treated compositions.

Composition 1 served as an image sample with no resin substitution. The compositions differed from one another in that there was a substitution in Composition 2 while the resin solids were only due to sodium chloride in composition 3 (the composition according to the invention) a resin substitution by mixing sodium chloride with urea-formaldehyde monomers.

In Composition 2, 19.5 parts of solid resin were replaced with 19.5 parts of solid sodium chloride.

In Composition 3, 39 parts of solid resin passed through Replaced 19.5 parts of the solid reactive catalyst (i.e. sodium chloride, urea and formaldehyde).

In composition 1 there was therefore a substitution of 1: 1 before, while in composition 2 a substitution of

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1: 2 was present.

The particle board produced with both mixtures had the same mechanical properties, although the composition 3 had a lower solids content. In both cases the chipboard was manufactured according to the bison system, i.e. H. with a continuous shift formation under controlled conditions that were kept constant in both cases:

Moisture of the mat before the Press 10 , 5 - 0, Pressing temperature 210 ⁰ C pressure 35 kg / cm

The properties (quality) of the particle boards produced are given in Table IV below.

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Table IV Components in parts by weight samples

ABA - BA— B.

Urea formaldehyde resin 100 200 90 180 80 160

Solids content of the urea-formaldehyde resin 65 130 58.5 117.00 52 104.0

Ammonium chloride (20% solution) - 8.0 - 8.0 - 8.0

Water 68.5 31 72.0 38.0 66.17 26.33

Ammonia from 25 ° Baume 1.5 1.0 1.5 1.0 1.5 1.0

Sodium Chloride (100%) - - 6.5 13.0

ο »Sodium Chloride A + B - 19.5

to (ι)

co ^v 'reactive catalyst 100% solids - - - - 6.5 13.0

- * "" 100 % solids A ₊ B - - 19.5

cn '

^ Water - - ₌ 15.83 31.67

^ Total amount of resin solution

Total solids

Solids content in%

Parts of the substituted (replaced) resin solids Parts of the resin solids A -Substitution A + B % resin substituted by A ₊ B

Ratio of added solid substituent to substituted resin solids

170 00 - 240, 00 170.00 19 240.00 5 170.00 39 240.00 , 0 65 - 131, 6th 65.0 10 131.6 58.50 20th 118.60 38, 3 - 54, 8th 38.2 1: 1 54.8 34.4 1: 49.4 2 pp
cn - - 6.5 13.0 13.0 26.0

~ 27Fig. 951

properties

3 density in kg / m

Thickness in mm

Young's modulus L

2 tensile strength in kp / cm

2 Flexural strength in kp / cm

% Water absorption after 24 hours of immersion

% Increase in swelling after immersion for 24 hours

645 sample •
• 19th 3 1 16.1 2 10 625 24500 630 71 16.2 4.5 16.5 23800 235 25,000 4.8 45 5.0 240 14th 223 53 lysators 50 16 17th

Components of the reactive catalyst: urea (100%)
Formaldehyde 100 "L
Sodium chloride 100 %

total 100

Example 5

The novelty of the present invention arises from the fact that when high degrees of substitution are desired are, it is absolutely necessary to use the mixture according to the invention to be used to spray the supply in one stage, as is done with all types of systems used for chipboard production can be used.

If only sodium chloride is added to the resin, without adding the urea and formaldehyde monomers, it is also disregarded from the fact that the speed is slow, as shown in the previous examples already described, separate spraying of the wood chips with sodium chloride

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required with subsequent drying of the wood mixture and further spraying with adhesive. This requires the use of additional devices that are costly and reduce production.

The additional steps are necessary because of the low solubility of sodium chloride in and also because of the fact that sodium chloride is in water Case the resin substitution is achieved by adding such an amount of solids content, which is equal to the amount of solid Substances of the substituted resin is. To replace (substitute) higher amounts of resin, there is too much water in the mixture required, which cannot be dried in one step in the press within the normal pressing times.

The mixture according to the invention can very well be used to replace higher Amounts of resin can be used without using too much water, and being the manufacture (production) in one Stage is possible, as is normally done in the manufacture of chipboard, without the production stages changing at all. According to the invention, this is possible due to the fact that the solubility in water is higher and therefore less water is used, but also the substitution is achieved by adding only half the amount of the substituted material, calculated as solid material.

To achieve the same degree of high substitution (35 % in the present example) when using the reactive catalyst according to the invention, a longer gel time and therefore a higher production rate are obtained (mixture 3). When using only sodium chloride without adding the urea and formaldehyde monomers

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you get a much longer gel time because of the added substituents in this case act as retarders instead of catalysts (mixture 2). All of the points mentioned arise from the mixtures of the following Table V. Three mixtures are shown in this table:

Mixture 1 is regarded as a blank in which the resin is used without any substituents (substitutes). The mixture 2 contains only sodium chloride, which replaces the resin, and the mixture 3 contains the reactive according to the invention Catalyst, d. H. a mixture of sodium chloride and urea-formaldehyde monomers. The percentage of the substituted hares is 35% in each case in mixes 2 and 3. In Mix 3 there were 37.5 parts of the reactive Catalyst was added, which replaced 68.5 parts of solid resin, while 68.5 parts of sodium chloride were added to the mixture containing the same amount of resin, i.e. H. 68.5 parts of resin. This shows that according to the invention there is a substitution of 1: 1.8 was achieved, while using only sodium chloride a substitution of 1: 1 was achieved.

The total amount of the resin solution in mixture 3, which contained the reactive catalyst according to the invention, was kept at the same value as in mixture 1. This was not possible in the case of mixture 2, in which only Sodium chloride was added because of the large amount of water required in the mixture due to the high resin substitution.

The gel time of the blank sample was 60 seconds. In the most responsive Catalyst-containing mixture 3 is obtained a lower gel time of 40 seconds, which increases production

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rates or speeds allowed; in mixture 2, in which only sodium chloride was used, the gel time was 110 sec. As the added components acted as retardants rather than catalysts.

In all 3 cases, column A relates to the solution used for spraying fine wood flour, which is used for production the outer surface of the chipboard was used, while column B in all 3 cases relates to the refers to the solution used for spraying wood chips that were used to make the core of the particle board.

Using the resin mixtures as given in the 3 cases in Table V, particle boards were produced. The manufacturing process used was the bison system and the conditions were met in all 3 Cases kept constant:

Moisture of the mat before pressing 10.5 * 0.5% pressing temperature 120 C

Pressure 35 kg / cm

The quality of the chipboard produced corresponded to DIN standards 52 360 to 52 365 and there were no differences in cases 1 and 3. In case 2, which contained only the sodium chloride instead of the reactive catalyst according to the invention, the properties of the particle board produced could not be measured because the boards obtained had already expanded during the normal pressing times. This shows that the sodium chloride used itself cannot result in high degrees of substitution, of the order of 35 % , if it is used for the production of chipboard / only a single spray stage by the process known per se.

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Urea formaldehyde resin resin solids ammonium chloride (20% solution) Water ammonia from 25 trees sodium chloride (100%) Sodium chloride A + B

reactive catalyst (100 %) reactive catalyst A + B water

Total amount of resin solution

Table V A. ) - 1 5 - B. A. 2 5 68 B. , 5 - 5 A. 3 B. 5 45 100 5 200 65 130 65 130 65 - 130 42 - 84, 161.5 42 84.5 - 8th - 8th 0 - 8th 68, 31 - 5 68.5 31 If 1.0 1, If 1.5 1.0 - 23 45, - ■ - - 12.5 - 25th - 82 22.5 37,

170

240

213.5 346.0 170.0 240

Table V continued

Total solids content Solids content in% parts of the substituted solid resin parts of the solid resin substituted by A + B% resin substituted by A + B

Ratio of solid substituent added to substituted resin solids

Gel time in sec.

65
38.2

- Β

131.6
54.8

(D

Components of the reactive catalyst in% urea (100 %) formaldehyde (calculated as 100% solids) sodium chloride (100 %)

AWAY

131.6
30.8 38
45.5

68.5

35

1: 1
110

54.5

54

23

—B

111.1 53 45.5

68.5
35

1: 1.8
40

IO

cn co cn

Example 6

This example illustrates the synergistic behavior found when a mixture of sodium chloride was added to the resin formulation along with the non-resinous condensation product of the urea and formaldehyde monomers. The results obtained are given in Table VI below, in which sample 1, apart from the usual additives which are added to the resin preparation for the production of chipboard, only contained sodium chloride and which had a gel time of 49 seconds. Sample 2 contained a urea-formaldehyde condensate and had a gel time of 51 seconds and samples 3 and 4 contained both sodium chloride and a urea-formaldehyde condensate, the sum of which was equal to the amount of sodium chloride used in sample 1, all calculated as 100 % Solids. The two samples 3 and 4 had a lower gel time than the samples 1 and 2 and the two samples 3 and 4 in particular had a gel time of 42 seconds.

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Table VI

Urea formaldehyde resin

(Solids content 65 %) 140 140 140 140

Ammonium chloride (20% solution in water) ammonia from 25 Baume sodium chloride (100 %) urea (100%)

Formaldehyde urea (18% solution in water)

water

total quantity

Gel time in seconds at 100 ° C

8th 8th 73 8th 8th 2 2 15th 2 2 12th ■ - 12th 8.55 5.5 - 1, 1.73 3.16 - 2, 2.15 4.18 64 72, 63.57 63.16 226 226 226 226 49 51 42 42

Formaldehyde-urea as a lower condensate with the following composition:

55 parts by weight of formaldehyde 25 parts by weight of urea 20 parts by weight of water

Example 7

This example illustrates the synergistic performance that has been observed when a mixture of potassium chloride resin formulation was added together with the condensation product of urea and formaldehyde monomers. The results obtained are given in Table VII below, in which sample 1 represents the blank sample which contained water instead of the catalyst according to the invention. Sample 2 contained potassium chloride and sample 3 contained a mixture of potassium chloride and a condensate of the urea and formaldehyde monomers.

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Sample 1 had a gel time of 93 seconds. Sample 2 had a weak catalytic effect with a gel time of 82 sec, the sample 3, the reactive according to the invention Containing catalyst, however, showed a surprisingly high catalytic effect with a gel time of 42 seconds.

salary 65%)
Ammonium chloride (20% <ammonia from 25 Baume potassium chloride (100%) urea (100 7.)

Formaldehyde urea (80% solution in water)

water

total quantity

Gel time in seconds at 100 ° C

Table VII 1 · (Solid
140 2 3 solution in water) 8 140 140 3 8th 8th - 3 3 - 12th 12th - - 7.38 75 - 9 226 63 46.62 93 226 226 82 42

Formaldehyde-urea as a lower condensate with the following composition:

55 parts by weight of formaldehyde 25 parts by weight of urea 20 parts by weight of water

Example 8

This example concerns the production of a veneered particle board. It explains in particular the fact that the inventive Catalyst also for gluing flat boards (panels), e.g. B. for the production of plywood,

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Laminated boards, veneered boards (boards) or other multilayer boards or boards can be used. In this case, a Tianna type veneer sheet became one Thickness of 0.6 mm and with a moisture content of 10% on both surfaces of a sanded chipboard with a thickness of 15 mm, a size of 185 χ 305 cm and one Glued on moisture content of 9%. The glue was spread on the chipboard by means of a glue spreading device.

2 The plates were under a pressure of 7 kp / cm at a Pressed temperature of 120 C. Two samples are given. In sample 1, the normal glue preparation was used while a preparation according to the invention was used in sample 2. The preparations are shown in Table VIII below specified.

While the plates produced with the preparation according to sample 1 required a pressing time of 2 minutes, the plates required Plates produced with the preparation according to sample 2 only have a pressing time of 1.7 minutes The glue preparation used for the manufacture of veneered particle board had the following Characteristics:

Increase in production speed by 15% Glue savings 26 %

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100 70 8th 8th - 6.00 - 1.62 - 0.83 - 21.55 7th 10

-Sun -

Table VIII

1 2

Urea-formaldehyde resin (solids content

65%)

Ammonium chloride (20% solution in water) Sodium chloride

Urea (100%)

Formaldehyde (100%)

water

Total 115 118

Example 9

This example illustrates the synergistic behavior which was observed when a mixture of sodium chloride together with urea and formaldehyde monomers was added to a resin preparation based on a melamine-formaldehyde resin. The resin used was
Kauramin 542 from BASF.

The results obtained are shown in Table IX below. Sample 1 was a blank sample. Sample 2 contained, apart from the usual resin preparation, ammonium chloride and ammonia as well as sodium chloride. Sample 3 contained, apart from the usual resin preparation, ammonium chloride and ammonia as well as urea and formaldehyde. All of these samples had the same gel time of 65 seconds. Sample 4 contained, apart from the usual resin preparation, ammonium chloride and ammonia as well as urea, formaldehyde and sodium chloride, with the grand total of the added mixture is equal to the amount in the samples

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2 and 3 added individual components. Sample 4 therefore represents an example of the use of the invention Catalyst and it actually had a much shorter gel time of 48 seconds.

Table IX

Melamine formaldehyde resin (solids content 65 X)

Ammonium chloride (20% solution
in water)

Ammonia from 25 trees
Sodium chloride (100%)
Urea (100 %)
Formaldehyde (100 %)
water

total quantity

Gel time in seconds at 100 ° C

Similar results can be obtained if in the above examples the sodium or potassium chloride is replaced by lithium chloride or fluorides, bromides or iodides of sodium, potassium or lithium.

1 2 3 2 4th 2 140 140 140 65 140 65 8th 8th 8th 15th 8th 15th 2 2 2 2 - 12th - 12th - - 3, 3, - - 1, 1, 76 64 71 59, 226 226 226 226 65 65 65 48

809815/0914

Claims (8)

Reactive catalyst for the polycondensation of urea-formaldehyde resins, which are used to connect water-permeable Cellulose particles can be used when using it in combination with a known catalyst the speed or rate of polycondensation of the resin increases and at the same time the use of smaller amounts Resin solids allowed without loss of bond strength, characterized in that that it contains or consists of a concentrated aqueous solution of a mixture of organic and inorganic Components, whereby the organic components are formaldehyde and urea or a non-resinous one Condensation product of formaldehyde and urea and the inorganic component is a water-soluble one Alkali metal halide is. 2. Catalyst according to claim 1, characterized in that it contains the organic and inorganic components in a ratio of 0.1 to 1.5 parts by weight of the organic components to 1.0 part by weight of the inorganic component contains, the amount of water depending on the solubility of the organic and inorganic components and the one used for the Solids content required depends on the manufacturing system. 3. Catalyst according to claim 1 or 2, characterized in that that the organic components are formaldehyde and urea and the inorganic component Sodium chloride. 809815/0914 ORIGINAL INSPECTED 4. Catalyst according to one of claims 1 to 3, characterized in that it is the urea-formaldehyde resin in in an amount of 1 to 30% by weight, based on the resin solids, together with the usual amounts of ammonium chloride so that production speeds can be increased by up to 30% while at the same time up to 30 weight percent less resin solids can be used without any loss of bond strength 5. Catalyst according to one of claims 1 to 4, characterized in that it is the urea-formaldehyde resin in one An amount of 20 parts by weight is added, giving 60 parts by weight of resin solids instead of 100 parts by weight of resin solids can be used. 6. Catalyst according to one of claims 1 to 5, characterized characterized in that it increases the rate of polycondensation of the resin at high temperatures without raise them at room temperature. 7. Process for the production of chipboard with urea-formaldehyde resins, characterized in that a reactive catalyst according to any one of claims 1 to 6 is used will. 8. The method according to claim 7, characterized in that chipboard is produced which is free from formaldehyde odor are. 809815 / 09U