DK145499B - PROCEDURE FOR POLYCONDENSATION OF Aqueous Urea or MELAMINE FORMALDEHYDE-RESIN BINDING AGENTS WITH THE CONNECTION OF WATER-PERMITTED CELLULOUS DEMODELIDE DIVIDUDE SUBSTITUDE - Google Patents

Description

(19) DENMARK (WJ

t \ Ra /

IP (12) PUBLICATION MANUAL (n) 145499B

PATENT AND TRADEMARKET DIRECTORATE

(21) Application No. 1578/78 (51) IntCI.8 C 08 G T 2/0 2 (22) Filing date 10 Apr. 1978 C08K 3/24 (24) Running day Apr 10 1978 C 09 J 3/16 (41) Aim. available Oct 28 1978 (44) Posted 29 Nov. 1982 (86) International application # - (86) International filing day - (85) Continuation day - (62) Master application no -

(30) Priority 27-Apr. 1977 # 55301/77 # GR

(71) Applicant TEUKROS HANDELSGESELLSCHAFT AG, CK-4010 Basel, CH.

(72) Inventor Andrew C. Markessini, GR.

(74) International Patent Bureau.

(54) A method of polycondensation of aqueous urea or molar min-formaldehyde resin binders during the simultaneous bonding of water-permeable cellulose products and resin-substituting binder additives to carry out the process.

The invention relates to a process for polycondensation of aqueous urea or melamine-formaldehyde resin binder during the simultaneous bonding of water-permeable cellulose products, in particular bonding to particle board, in which process 1 uses usual catalysts for polycondensation of amine resin additives and amine resins one aqueous solution of selective alkali metal halide, wherein the polycondensation takes place at elevated temperature and pressure. In addition, the invention relates to a resin-substituting binder additive for practicing the process of the invention.

From US Patent No. 3,697,355 it is known to use alkaline metal halide, especially sodium chloride, in combination with cellulose products, together with urea-formaldehyde resin binder. The halide salt can, by this prior art, replace solid resin binder substances in a weight ratio of 1: 1.

According to an embodiment of this prior art, the halide salt used in solid, dissolved or suspended form can be added to the boiler in which the urea-formaldehyde resin has just been prepared.

In such an embodiment, sodium chloride can be used in an amount which replaces up to a maximum of 13% of the resins, since larger amounts of sodium chloride are not dissolved in the resin.

If said prior art sodium chloride is to replace larger quantities of resins, e.g. up to approx. 30%, this according to said US patent requires a two-step process in which the sodium chloride is first sprayed as a separate aqueous solution on the cellulose product to be bonded, which product is then dried, after which the resin binder is applied.

In the above-mentioned prior art, the halide salt used, as mentioned, can at most replace the same amount of solid resin solids. Furthermore, the halide salt has no promotional effect on the rate of production which can even be reduced at high levels of halide salt, and further, when added to the resin binder, has an undesirable density enhancing effect.

By using acid curing catalysts, the production rate can be increased, but beyond a certain limit this occurs while simultaneously deteriorating the properties of the bonded material. Addition of the known catalysts in large quantities makes it possible to carry out the polycondensation at even room temperature (despite the addition of retention agents such as ammonia or hexamethylene tetramine), but at the same time the durability of the binder at room temperature is reduced, leading to a hardening prior to introduction into the press and to the known disadvantages associated with such a phenomenon.

The process of the present invention, which is of the initially specified nature, is characterized in that the alkali metal halide is incorporated into the binder in the form of an aqueous solution containing, in dissolved form, an organic material consisting of formaldehyde and urea or of a combination of a non-resinous urea-formaldehyde condensation product and urea, the aqueous solution optionally further containing a surfactant wherein the dry matter weight ratio of the alkali metal halide to said organic material ranges from 0.1 to 1.5 parts by weight of organic material. 1, 0 parts by weight of the alkali metal halide, and the alkali metal halide and said organic material are incorporated into the binder in a total dry matter weight amount corresponding to 1-30% by weight of the solid amino resin substances in the amino resin binder when used without any resin-substitutive additive.

It is preferred according to the invention that as the alkali metal halide, sodium chloride be used and as said organic material formaldehyde and urea are used. '

The process of the invention results in increased product velocity compared to a process using the same resin binder without additive or with sodium chloride alone as additive. : -

Furthermore, the present process entails a saving of resin binder, since it has been found that the weight amount of solid resin substances in the binder can be reduced by up to twice the dry weight weight amount of the additive used. These advantages are illustrated in the examples given below.

There is a synergistic effect between the alkali metal halide of the additive and its organic material, the effect obtained being greater than the sum of the effects obtained by using said components separately.

It should be noted that due to the above-mentioned synergistic effect between the halide salt of the additive and its Organic Material, it is natural to consider the additive as one whole, and this also applies to calculations made below for the additive's resin-substituting and saving effect, however- also, if the organic material of the additive is theoretically included as resin substances in the total binder, there is one significant ··· resin saving compared to, for example, the prior art mentioned above, which is also illustrated in the examples below.

When the additive is used in relatively small amounts of, for example, 3-10%, in addition to the above advantages in terms of production rate and resin saving, an improvement in the properties of the bonded final product compared with the products obtained by the above-mentioned known methods is also obtained. in greater quantities, such as 30%, no such additional improvement in the properties of the final product is observed. * 4 145Å99

The production rate can be increased at higher temperatures, without deteriorating the properties of the bonded product, to such values that would never be achieved by simple addition of acid curing catalysts. At the same time, the present method has the advantage that the additive used is effective only at high temperatures and therefore substantially only increases the production rate at the temperature of the press. This avoids unwanted hardening phenomena at room temperature.

The additive used in the present process is added to the resin binder simultaneously with other chemicals well known to the binder, such as ammonium chloride or sulfate, ammonia or paraffin emulsion, in the actual application of the binder to bond cellulose products.

Thus, regardless of the amount of additive used in the present process, it is a single step spray of the cellulose product by a method known per se.

Finally, the present process is associated with the advantage that the amount of free formaldehyde in the manufacture of cellulose products is significantly reduced as a result of the reduced amount of resin binder used, and the products obtained, such as boards or sheets, are so to say odorless.

The resin-substituting binder additive encompassed by the invention for carrying out the process of the present invention is an additive containing water-soluble alkali metal halide and according to the invention is characterized in that it consists of said alkali metal halide in the form of an aqueous solution containing an organic material containing an organic material consists of formaldehyde and urea or a combination of a non-resinous urea-formaldehyde condensation product and urea, which aqueous solution optionally further contains a surfactant wherein the dry matter weight ratio of the alkali metal halide to said organic material is from 0.1 to 1, 5 parts by weight of organic matter to 1.0 part by weight of alkali metal halide.

It is preferred according to the invention that the alkali metal halide is sodium chloride and said organic material is formaldehyde and urea.

The surfactant optionally contained in the additive solution is present in low amounts, for example from 0.1 to 2%, and serves to improve the distribution of the resin binder around the cellulose product.

145499 5

The present invention can be applied to all types of; cellulose products which are linked to resin b indemidia of the kind in question, e.g. cellulose products for the manufacture of particleboard using flat presses or; calendering elf wood veneers, such as plywood manufacture. The quality of boards and the board produced by the present method has been checked weekly over a period of 6 months without any deterioration of the properties. This shows that no polymer degradation occurs and that the aging properties of the boards and boards are similar to those of the usual manufacture.

The invention is further described by the following examples.

Example -1 .....

A constant amount of urea-formaldehyde resin (®Kaurite 285 ", pure urea-formaldehyde condensation product from BASE) was reacted with binder additive according to the invention under controlled temperature and pressure conditions, the additive varying depending on the proportions of the The additive was used not only, but in conjunction with a conventional catalyst usually consisting of ammonium chloride optionally containing hexamethylenetetramine. In Tables I and IA below, the synergistic effect of the organic additive in question is clearly shown. inorganic components.

Sample 1, which is to be considered a blank, which did not contain additives according to the invention, but as a catalyst containing only the known ammonium chloride, had a solidification time of 100 at 100 ° C. seconds.

Sample 2, in addition to aramonium chloride, also contained a certain amount of urea-formaldehyde and exhibited a slightly increased catalytic effect with a solidification time at 100 ° C of 85 seconds.

Sample 3, in addition to ammonium chloride, also contained a certain amount of sodium chloride, but no urea-formaldehyde, and it showed a slightly increased catalytic effect at 100 ° C with a solidification time of 80 seconds.

Sample 4, in addition to ammonium chloride, contained a mixture of urea-formaldehyde and sodium chloride, the total amount of the mixture added being equal to the amount of the single components added in samples 2 and 3. Samples 4, 5 and 6 showed an increased catalytic effect due to the synergistic behavior of the components used, and the solidification times obtained at 100 ° C were 60, 35 and 28 seconds, respectively.

The difference between samples 4, 5 and 6 was due to different proportions of the organic components used and the inorganic component of the additive solution. It was found that Sample 6, which contained the largest amount of organic matter, also exhibited the greatest catalytic effect.

Table I

Components Comparison According to the invention in parts by weight I 2 3 4 5 6

Urea formaldehyde resin (with a solids content of 65%) 140 140 140 140 140 140 Water 70 10 10 10 10 10

Additive Solution - 60 60 60 60 60

Ammonium chloride (20% solution in water) 12 12 12 12 12 12

Hexamethylenetetramine (20% solution in water) 888 888

Solidification times in seconds at 100 ° C 90 85 80 60 35 28

Additive Solution Components Weight Parts

Urea (100%) - 5.35 - 5.35 10.70 16.05

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 62.8 54.7

Total - 100.0 100.0 100.0 100.0 100.0

The tests listed in Table I are in accordance with the usual practice of solidification time measurements made by binder alone, but similar results are obtained when the binder is used in practice in the bonding of cellulose products, where the shorter solidification time means greater production speed.

The results shown in Table I are not due to different water contents in the samples, which is illustrated in Table IA below, where the amount of water is kept constant.

Table IA

Components Samples in parts by weight Comparison According to the invention

IA 2A 3A 4A 5A 6A

Urea-formaldehyde resin (with a solids content of 65%) 140 140 140 140 140 140

Water 10 10 10 10 10 10

Urea - 3.21 - 3.21 6.42 9.63

Formaldehyde (44%) - 3.75 - 3.75 7.50 11.25 (Calculated as formaldehyde 100%) - (1.65) - (1.65) (3.30) (4.95)

Sodium Chloride (100%) - - 12 12 12 12

Surfactant - 0.1 0.1 0.2 0.2 0.1 0.1

Ammonium chloride (20%) 12 12. 12 12 12 12

Hexamethylenetetramine (20% solution) 8 8 8 8 88

Solidification time in seconds 90 65 78 56 34 29

Example 2

This example illustrates the above advantages obtained by particle board manufacture when the additive of the invention is added to the resin binder.

Below are illustrated three cases in which the same total amount of resin binder solution was used. Differences existed with respect to the different amounts of the various components of the solution used, as indicated in Table II below. A comparison has been made between two resin binders with different concentrations of organic component in the additive according to the invention and a binder commonly used in the industry, ie. same resin binder as above, but without additive of the invention and without sodium chloride. It should be noted that columns A of Table II relate to the solution used for spraying fine wood flour used to prepare the outer surface of the particle board, while columns B relate to the solution used to prepare the core of the particle board.

The particle board was made in this example according to the Bison system, ie. under continuous layer formation under controlled conditions which were kept constant in all the illuminated cases. 20 liters of binder solution as indicated for samples ΙΑ, 2A and 3a were each sprayed on 100 kg of wood flour to the surface with a moisture content of 1-2%, while 13 liters of binder solution as indicated for samples IB, 2B and 3B were each sprayed on 100 kg wood chips. to the core with a moisture content of 1%:

Moisture of the mat prior to the press 10.5 - 0.5%

Pressure temperature 210 ° C

2

Pressure 35 kg / cm

The qualities of the particle board thus prepared showed no significant differences in the three cases (cf. the results in Table II). In Samples 2 and 3, the quality is slightly degraded, but the density is also lower, which as is known in the art usually results in poorer quality. However, the differences in quality fall within the accuracy of the method and are of no significance to ordinary particle board. The results in all cases fall within the requirements of German standard DIN 52 360 to 52 365.

Use of resin binder containing additives according to the invention led to a reduction of the pressing time, as stated below:

Sample 1: 9.25 seconds per mm of the non-abrasive (pain-treating) chipboard.

Sample 2: 8.00 seconds per mm of the non-abrasive or gravel-covered chipboard.

Sample 3: 7.00 seconds per mm of the unpainted chipboard plate.

Sample 3, which contained the largest amount of organic component relative to the inorganic component, showed the best results.

The results show that by using the additive according to the invention it is possible to reduce the pressing time in the manufacture of particle board, and at the same time it is possible, by using this additive, to reduce the use of resin by up to 17.3% (sample 2 ) or up to 22% (sample 3). If the organic material of the additive is theoretically included in the binder-forming resin material, - compared to samples 1-8 parts of sodium chloride in samples 2A and 3A, 16.3 parts and 13 parts of resin respectively, while in samples 2B and 3B 14 parts of sodium chloride replace 33 respectively. , 3 parts and 27.7 parts of resin, ie. exchange ratio significantly higher than 1: 1.

145499

Components in parts by weight Comparison According to the invention 1 2 3

A ——— B A ——— B A —-— B

Table II

samples

Urea-formaldehyde resin (with 65% solids content) 100.0 200.0 70.0 140.0 70.0.140.0

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

Water 68.5 31.0 58., 5 20.0 58.5 20.0

Ammonia, 25 ° Tree 1.5 1.0 1.5 2.0 1.5 2.0

Catalyst solution - - 40.0 70.0 40.0 70.0

Total amount 170.0 240.0 170.0 240.0 170.0 240.0

Components in catalyst solution

Urea (100%) - - 5.35 5.35 10.70 10.70

Formaldehyde (100%) - - 2.75 2.75 5.50 5.50

Sodium chloride (100%) - - 20.0 20.0 20.0 20.0

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

Water - - 70.9 70.9 62.8 62, B

Total Quantity - - 100.0 100.0 100.0 100.0

Properties Sample 1 2 3 Density (kg / m ^) 660 640 625

Thickness in mm 16.2 16.0 16.1

Elasticity module L 26 000 23 200 24 000 2

Tensile strength in kp / cm 5.0 4.5 4.2 Bending strength in kp / cm ^ 250 230 225

Water absorption in% after 24 hours immersion 40 45 52

Percentage increase of swelling after 24 hours immersion 13 15 20

Example 3

This example illustrates the increase in the rate or rate of particle board preparation obtained when the additive according to the invention (containing sodium chloride and urea-formaldehyde monomers) is added to the binder mixture, compared to the rate or rate obtained by separate addition. of sodium chloride (without urea-formaldehyde monomers).

The results obtained are set forth in Table III below, where Sample 1, in addition to the usual additions added to a resin blend for the production of particle board, contained only sodium chloride and exhibited a solidification time (property measured on the resin binder per se without cellulose particles present) of 80 seconds, while sample 2 contained the same additives as sample 1. but additional urea and formaldehyde monomers, as well as the same amount of sodium chloride, which had a solidification time of 28 seconds. It should be noted that this difference in solidification time is not due to a lower water content of sample 2 compared to sample 1, since a sample with the same composition as sample 2 but with the volume of water raised to 58 parts by weight showed a solidification time of 30 seconds.

Under similar conditions, particle boards were manufactured in a Bison plant without separation of the core and surface layer cellulose materials prior to the mixing machine. Of sample 1, 230 kg was sprayed on 130 kg of dry cellulose particles, resulting in a solid resin content (including sodium chloride) of 7.9% based on the dry wood. Similarly, 230 kg of Sample 2 was sprayed onto 160 kg of dry cellulose particles, resulting in a solid resin content of 7.3%, based on the dry wood. The production rate or speed of the particle board was 9 seconds per mm in the case of sample 1 and 7 seconds per mm in the case of sample 2. The mechanical properties obtained according to DIN 52 360 to 52 365 were essentially the same in the two cases, the deviations, as discussed above in connection with Example 2, fall within the accuracy of the measurement methods and the results obtained in all cases fall within the requirements of said DIN standards.

Table III

Components Samples in parts by weight Comparative Invention Equation 1 2

Urine tuff formaldehyde resin (dry matter content 65%) 140 140

Water 43.42

Ammonium chloride (20% solution in water) 12 12 (continued) 11 165499

Table III (continued)

Components Samples 1 parts by weight According to the equation invention 1 2

Hexamethylenetetramine 8 8

Sodium Chloride (100%) 12 12

Urea (100%) - 9.63

Formaldehyde (100%) -4.95

Total amount 230.00 230.00

The additive solution used for Sample 2 had the following composition: Weight portions.

Formaldehyde (100%) 4.95x

Urea (100%) 9.63

Sodium chloride (100%) 12

Water (8.42 parts contained in CH 2 O solution) 43.42 100.00.

x) 13.4 parts by weight 37% CI 2 O.

Table III (continued)

samples

According to Equation The Invention 1 2

Immersion time in seconds 80 28

Pressing time in seconds per mm thickness of the unpainted chipboard 9 7

Properties Sample 1 2 Density (kg / m2) 660 640

Thickness in mm 16.05 16.20

Elasticity module L 24 500 23 200 2

Tensile strength kp / cm 6.0 5.2 Bending strength in kp / cm2 235 240

Water absorption in% after 24 hours immersion 45 60

Swelling in% increase after 24 hours immersion 13.4 14.9 12 U5499

Example 4

This example illustrates the increased substitution of urea formaldehyde resin using the additive of the invention compared to the substitution obtained using only sodium chloride without the addition of urea and formaldehyde monomers, obtaining particle board which in the two cases exhibited equivalent mechanical properties.

In particular, this example illustrates the case where the substitution in the case of. sodium chloride was 1: 1 relative to the resin, while the resin substitution, in the case of the mixture of sodium chloride with urea and formaldehyde, was 1: 2. A stock of wood shavings, after pulverization, was treated with the compositions listed in Table IV below in the manner described below.

In the A tests, fine wood flour was sprayed, which was used to form the outer surfaces of the particle board, while the B tests concerned the spraying of wood chips used for the core of the particle board. The same amount of composition was sprayed on the same amount of wood as given below:

Sample 1A: 170 kg of the composition was sprayed onto 650 kg of dry wood flour, ie. 10% solid resin solids based on the dry wood flour.

Sample IB: 240 kg of the composition was sprayed on 1857 kg of dry wood chips, ie. 7% solid resin based on the dry wood chips.

Sample 2A: 170 kg of the composition was sprayed onto 650 kg of dry wood flour, ie. 9% solid resin solids based on the dry wood flour.

Sample 2B: 240 kg of the composition was sprayed on 1857 kg of dry wood chips, ie. 6.3% solids based on the dry wood chips.

Sample 3A: 170 kg of the composition was sprayed onto 650 kg of dry wood flour, ie. 8% solid resin solids based on the dry wood flour.

Sample 3B: 240 kg of the composition was sprayed on 1857 kg wood chips, ie. 5.6% solids based on the dry wood chips.

Sample 1 served as blank without resin substitution. The samples differed in that in Sample 2 there was only a substitution of resin solids with sodium chloride (known in the art), 13 145/199 while in Sample 3 (with additive according to the invention), a resin substitution with a mixture of sodium chloride and urea took place. formaldehyde monomers.

In Sample 2, 19.5 parts of solid Jiarplks were replaced with 19.5 parts of sodium chloride.

In Sample 3, 39 parts of solid resin were replaced with 19.5 parts of solid additives (i.e., sodium chloride, urea and formaldehyde).

Thus, in Sample 2, there was a 1: 1 substitution, while in Sample 3, a 1: 1 substitution was available.

If the organic material of the additive is theoretically included in the binder-forming resin material, - compared with samples 1-4.6 parts of sodium chloride in sample 3A, 11.1 parts of resin substances, while in sample 3B 9.2 parts of sodium chloride replaces 22.2 parts of resin substances. i.e. exchange ratios significantly higher than 1: 1, as obtained in samples 2A and 2B, respectively.

The particle board produced had the same mechanical properties, although sample 3 showed a lower solids content. In all three cases, particle boards were manufactured according to the Bison system, ie. with a continuous layering, controlled conditions are kept constant:

Moisture of mat prior to press 10.5-0.5%

Pressure temperature 210 ° C

Pressure 35 kg / cm2

The properties (quality) of the particleboard manufactured are listed in the following Table IV.

Table IV

samples

According to

Components in parts by weight Comparison. invention

A-i-B A --- B ft- ~ -—B

Urea formaldehyde resin 100 200 90 180 8Q 160 Solids content of 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, 25 ° Tree 1.5 1.0 1.5 1.0 1.5 1.0

Sodium Chloride (100%) - - 6.5 13.0 -

Sodium Chloride & + B) - 19.5 (continued) 14

Table IV (continued)

Components in parts by weight Samples

According to

Comparative Invention 1 2 3

A ——— B A ——— B A —-— B

(1)

Additive dry matter - - - - 6.5 13.0

Additive dry matter (A + B) - - 19.5

Water ~ - _ _ - 15.83 31.67

Total amount of resin solution 170.00 240.00 170.00 240.00 170.00 240.00

Total dry matter content 65 131.65 65.0 131.6 58.50 118.60 Solids content in% 38.3 54.8 38.2 54.8 34.4 49.4

Parts of substituted (replaced) resin solids - - 6.5 13.0 13.0 26.0

Parts of resin solids substituted (A + B) - 19.5 39.0% Resin substituted (A + B) - 10 20

Ratio: between substituted solids and substituted resin solids - 1: 1 1: 2

Properties Sample 12 3 Density in kg / no 645 630 625

Thickness in mm 16.1 16.5 16.2

Elasticity module L 24 500 25 000 23 800 2

Tensile strength in kp / cm 4.5 5.0 4.8 Bending strength in kp / cm ^ 235 223 240

Water absorption in% after 24 hours immersion 45 50 53

Swelling in% increase after 24 hours immersion 14 17 16 (1)

Composition of additive used according to the invention:

Water 256 68.65

Urea (100%) 19 5.09

Formaldehyde (37%) 27 7.23

Sodium Chloride (100%) 71 19.03

Total 373 100.00.

145499 15

Example 5

The novelty of the present invention is evident from the fact that when high degrees of substitution are desired, it is still possible to use the additive of the invention to spray the cellulose product in a single step, as is the case with all types of systems used in particle board manufacturing.

In contrast, when sodium chloride is added to the resin only, without the addition of urea and formaldehyde monomers, at high substitution rates, in addition to the low rate, as shown in the examples described above, a separate spraying of the wood chips with sodium chloride and subsequent drying 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 poor solubility of sodium chloride in water, which sodium chloride must be used in a dry matter amount equal to the amount of dry matter from the substituted resin. To replace (substitute) higher resin quantities, the mixture requires too much water that cannot be dried in a single step of the press within the normal press times.

The additive according to the invention can very well be used to replace higher amounts of resin without using too much water, and the production (production) is possible in a single step, as is usually the case in particle board production, without changing the production steps at all. This is possible because urea and formaldehyde are more soluble in water than sodium chloride and therefore less water is used and also because the substitution is obtained by adding only half the amount of the substituted material calculated as dry matter.

At the same high degree of substitution (35% in the present case), using the additive according to the invention, a shorter solidification time and therefore a higher production rate (mixture 3 in Table V) is obtained, whereas the use of only sodium chloride without the addition of urea and formaldehyde. monomers cause significantly longer solidification time, since in this case the added substituents act as retarding agents rather than as catalysts (mixture 2). This is shown in Table V. The following table describes three mixtures: · - U5499 16

Mixture 1 is to be considered a blank test in which the resin was used without any substituents (substitutes). Mixture 2 contained as resin substitute only sodium chloride, and mixture 3 contained as resin substitute additive according to the invention, i. a mixture of sodium chloride and urea-formaldehyde monomers. The percentage of substituted resin in mixtures 2 and 3 was 35%. In mixture 3, 37.5 parts of additive solids were added, replacing 68.5 parts of solid resin, while in mixture 2 68.5 parts of sodium chloride were added, replacing the same amount of resin, i. 68.5 parts of resin. This shows that, using the additive of the invention, a substitution of 1: 1.8 was obtained, while using sodium chloride alone, a 1: 1 substitution was obtained.

The total amount of the resin solution of the mixture 3 illustrating the invention was kept at the same value as for the mixture 1. This was not possible in the case of the mixture 2, to which only sodium chloride was used, due to the large amount of water needed in the mixture. due to the high resin substitution.

The settling time for the blank was 60 seconds. With the mixture 3 containing the additive according to the invention, a lower solidification time of 40 seconds was obtained, which allowed higher production rates or rates. With the mixture 2, in which only sodium chloride was used, the solidification time was 110 seconds when the added components acted as retarding agents rather than as catalysts.

Column A relates in all three cases to the solution used for spraying fine wood flour used to produce the outer surface of the particle board, while in all three cases column B relates to the solution used for spraying wood chips used to make of the core of the particleboard.

Using the resin mixtures listed in Table V for the three cases, particle board was prepared. The manufacturing method used was the Bison system and the following manufacturing conditions were kept constant in all three cases: • j ·

Moisture of mat prior to press 10.5 - 0.5%

Pressure temperature 120 C

Pressure 35 kg / cm2 145499 17

The quality of the particleboard manufactured 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 sodium chloride instead of the additive according to the invention, the properties of the particleboard manufactured could cannot be measured because the sheets produced had already expanded by the normal press times. This showed that sodium chloride used alone could not give a high degree of substitution of the order of 35% if only a single spraying step was used for the particle board preparation, as preferred.

Table V According to

Components in parts by weight Comparison of the invention

A B A B A B

Aqueous 65% urea-formaldehyde resin 100 200 65 130 65 130 (Resin solids in this resin 65 130 42 84.5 42 84.5). , pix

Ammonium chloride (20% solution) - 8-8-8

Water 68.5 31 - - 68.5 31

Ammonia, 25 ° Tree 1.5 1.0 1.5 1.0 1.5 1.0

Sodium chloride (100%) - - 23 45.5

Sodium Chloride (A + B) - 68.5

Additive (100%) + - 12.5

Additive (A + B) - - 37.5

Water (additive solution) - - 82 161.5 22.5 45

Total amount of resin solution 170 240 213.5 346.0 170.0 240

Total dry matter content 65 131. 65 131. 54 54 111.1 Dry matter content in% 38.2 54.8 30.8 38 54 53

Parts resin solids - - 23 45.5 23 45.5 substituted

Parts of resin solids - 68.5 68.5 substituted (A + B)% Resin substituted (A + B) - 35 35

Ratio of added solid substituent to substituted resin solids - 1: 1 1: 1.8

Solidification time in seconds 60 110 40 145499 18 (1)

Components in additive, dry matter in%

Urea (100%) 30

Formaldehyde (calculated as 100% solids) Sodium chloride (100%) 55

Example A

This example illustrates the synergistic behavior found when a mixture of sodium chloride, a non-resinous condensation product of urea and formaldehyde comonomers and urea is added to the resin composition. The results obtained are given in Table VI below, where Sample 1, in addition to the usual additives added to resin compositions for the manufacture of particle board, contained only sodium chloride and had a solidification time of 49 seconds. Sample 2 contained a urea-phenyldehyde condensate and urea and had a clotting time of 51 seconds, and samples 3 and 4 contained both sodium chloride, a urea-formaldehyde condensate and urea, the sum of which was equal to the sodium chloride used in sample 1. as 100% dry matter. The two samples 3 and 4 had a shorter solidification time than samples 1 and 2, namely a solidification time of 42 seconds.

Table VI

Components in parts by weight Comparison According to the invention 1 2 3 4

Urea-formaldehyde resin (dry matter content 65%) 140 140 140 140 'Ammonium chloride (20% solution in water) 8888

Ammonia, 25 ° Bauml 2222

Sodium Chloride (100%) 12 - 8.5 5.5

Urea (100%) - 1.73 1.73 3.16

Formaldehyde urea (80% rs solution in water) - 2.15 2.15 4.18

Water 64 72.12 63.57 63.16

Total Quantity 226 226 226 226

Immersion time in seconds at 100 ° C. Solution prepared by dissolving in 20 parts by weight of water a non-resinous condensation product made from 55 parts by weight of formaldehyde and 25 parts by weight of urea.

v Solidification time is measured on the resin binder per se without cellulose product present and shows the binder's suitability for bonding cellulose products.

Example 6

This example illustrates the synergistic behavior found when a mixture of potassium chloride, a non-resinous condensation product of urea and formaldehyde nonarians, and urea is added to the resin composition. The results obtained are set forth in Table VII below, where Sample 1 is the blank containing water instead of the additive of the invention. Sample 2 contained potassium chloride, and sample 3 contained a mixture of potassium chloride, a condensate of urea and formaldehyde nanonomers, and urea.

Sample 1 had a solidification time of 93 seconds, sample 2 showed a weak catalytic effect with a solidification time of 82 seconds, and sample 3 containing additives according to the invention (consisting of the potassium chloride, urea, formaldehyde urea and water listed in Table VII). , showed a surprisingly high catalytic effect with a solidification time of 42 seconds.

Table VII

According to

Components in parts by weight Comparative Invention 12 3

Urea-formaldehyde resin (dry matter content 65%) 140 140 140

Ammonium chloride (20% solution in water) 8 8 8

Ammonia, 25 ° Tree 3 3 3

Potassium Chloride (100%) - 12 12

Urea (100%) - - 7.38

Formaldehyde urea (80% solution in water) - - 9

Water 75 63 46.62

Total Quantity 226 226 226

Immersion time in seconds at 100 ° C. Solution prepared by dissolving in 20 parts by weight of water a non-resinous condensation product made from 55 parts by weight of formaldehyde and 25 parts by weight of urea.

(and v. Depletion time is measured on the resin binder per se without any cellulose product present and shows the binder's suitability for bonding cellulose products.

In the above Table VII, the total amount of resin binder is the same for all three samples. The following tables VIIA and VIIB illustrate that it is not different water contents but use of the additive according to the invention that is the cause of the significant decrease in solidification time. Table VIIA illustrates the case where the amounts of water used in Table VII have been removed, adding only 2.3 parts of water corresponding to the water content of 11.5 parts of 80% formaldehyde urea to the samples 1A and 2A. solution, while Table VIIB illustrates the case where the amount of water in the resin binder identical to sample 3 of Table VII (sample 3B of Table VIIB) is raised to 75 parts as in sample 1 of Table VII (sample 4B of Table VIIB).

Table VIIA

According to

Components in parts by weight Comparative invention

1A 2A 3A

Urea formaldehyde resin 140 140 140 (dry matter content 65%)

Ammonium chloride (20% solution 88 8 in water)

Ammonia, 25 ° Tree 33 3 • Potassium chloride (100%) - 12 12

Urea (100%) - - 7.88

Formaldehyde urea (80%) - - 11.5 (calculated as 100%) (9)

Water 2.3 2.3

Solidification time in seconds 114 112 61 145499 21

Table VIIB

Components 1 parts by weight Comparative According to the invention

IB 2B 3B 4B

Urea-formaldehyde resin (dry matter content 65%) 140 140 140 140

Ammonium chloride (20% solution in water) 888 8

Ammonia, 25 ° Tree 3 3 33

Potassium Chloride (100%) - 12 12 12

Urea (100%) - - 7.38 7.38

Formaldehyde urea (80% solution in water) - 9 9

Water 75 63 46.62 75 +)

Solidification time in seconds 136 106 69 85 +)

The differences in absolute numerical values between Table VII and Table VIIB are due to differences in such factors as material temperature, quantity and age, which may vary from experimental series to experimental series, but are the same within each experimental series.

Example 7

This example relates to the manufacture of a veneered chipboard.

In particular, it illustrates the fact that the additive according to the invention can also be used for bonding flat boards (sheets), such as for the manufacture of plywood, sheets, veneered sheets (boards) or other multilayer sheets or boards. In this case, a Tianna-type veneer film of 0.6 mm thickness and a moisture content of 10% was glued on both surfaces of a 15 mm thick enamelled chipboard, 185 x 305 cm in size and a moisture content of 9%. The glue was distributed on the chipboard by means of a glue distributor.

2

The plates were pressed at a pressure of 7 kp / cm at a temperature of 120 ° C. There were two tests. For sample 1, the normal adhesive composition was used, while for sample 2 an additive composition according to the invention was used. The compositions are listed in Table VIII below.

While the sheets made with the composition of Sample 1 required a pressing time of 2 minutes, the sheets made with the composition of Sample 2 required only a pressing time of 1.7 minutes.

The adhesive composition used for the manufacture of veneered particle board which made use of the additive according to the invention resulted in the following:

Increase in production rate by 15%

Limb saving 26%.

145499 22

Table VIII

Together- According to

Components in parts by weight of the invention 1 2

Urea-formaldehyde resin (dry matter content 65%) 100 70

Ammonium chloride (20% solution in water) 8 8

Sodium Chloride - 6.00

Urea (100%) - 1.62

Formaldehyde (100%) - 0.83

Water 21.55

Mel 7 10

Total Quantity 115 118

Example B

This example illustrates the synergistic behavior found when a mixture of sodium chloride and urea and formaldehyde monomers is added to a resin composition based on a melamine-formaldehyde resin. For the resin used, there was (refer to "Kauramine 542" (a modified melamine-urea-formaldehyde condensation resin from BASF).

The results obtained are given in Table IX below. Sample 1 was a blank test. Sample 2 contained, in addition to the usual resin composition, ammonium chloride and ammonia as well as sodium chloride. Sample 3 contained, in addition to the usual resin composition, ammonium chloride and ammonia as well as urea and formaldehyde. All of these samples had the same solidification time of 65 seconds. Sample 4 contained, in addition to the usual resin composition, ammonium chloride and ammonia as well as urea, formaldehyde and sodium chloride, the total amount of the mixture added being equal to the amount of the single components added in samples 2 and 3. Sample 4 had a much shorter solidification time of 48 seconds.

Claims (2)

Table IX According to Components 1 parts by weight Comparison of the Invention 1 2 3 4 Meylamine-formaldehyde resin (solids content 65%) 140 140 140 140 Ammonium chloride (20% solution in water) 8888 Ammonia, 25 ° Baumé 2 2 22 Sodium chloride (100 %) 12 12 Urea (100%) - - 3.2 3.2 Formaldehyde (100%) - - 1.65 1.65 Water 76 64 71.15 59.15 Total amount 226 226 226 226 Solidification time in seconds at 100 ° C 65 65 65 48 Similar results could be obtained when in the above examples sodium or potassium chloride was replaced with lithium chloride or with fluorides, bromides or iodides of sodium, potassium or lithium. A process for polycondensation of aqueous urea or melamine-formaldehyde resin binders during simultaneous bonding of water-permeable cellulose products, in particular bonding to particle board, using the usual catalysts for polycondensation of amino resins, water resin additive solvent substituents and resin substituents. and wherein the polycondensation takes place at elevated temperature and pressure, characterized in that the alkali metal halide is incorporated into the binder in the form of an aqueous solution containing in dissolved form an organic material consisting of formaldehyde and urea or a combination of a -resinous urea-formaldehyde condensation product and urea, which optionally further comprises a surfactant wherein the dry matter weight ratio of the alkali metal halide to said organic material is from 0.1 to 1.5 parts by weight of organic material. e to 1.0 part by weight of alkali metal halide, and the alkali metal halide and said organic material are incorporated into