AU603804B2 - Substitute for amino and phenolic resins - Google Patents

Description

a C 0MM 0 N WE ALTH 6F A US TRA LI A P~ATET AC 1952/2-9 37 (original) FOR OFFICE USE Class Ir Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: r '~f Class Related Art: 4 *A 4 4* 0 .4 4*

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This document contains the ame-udments made under Section 49 and is correct for printing.

Name of Applicant: Address of Applicant: ENIGMA N.V.

De Ruyterkade 62, P.O. Box.812, Curacao, NETHERLANDS ANTILLES *0 %9

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Address for Service: DAVIES COLLISON, Patent Attorneys, I Little Collins Street, Melbourne, 3000.

Complete Specification for the invention entitled: "SUBSTITUTE FOR AMINO AND PHENOLIC RESINS" The following statement is a full description of this invention, including the best method of performing it known to us -1- 1 A SThe present invention relates to a substitute for amino and phenolic resins in the polycondensation of such resins based on formaldehyde for bonding water penetrable cellulosic particles thus allowing lower amounts of resin solids to be used while at the same time reducing the free formaldehyde S of the resulting board without imparting any loss in bonding strength, without requiring any extra steps in the pro- C duction, without changing the curing rate of the production, Swithout causing any problem to the boilers when burning C t particleboard sander dust or edges from cutting saws and t without reducing the tack properties of the resin mixture.

The said substitute is comprised mainly of a solution of t t C" a) either an aldehyde together with an amide or together with a phenol, or a non-resinous condensation product ,20 of formaldehyde and urea, and b) a sugar or a sugar derivative or their by-products or a starch or a mixture thereof, and/or I c) a raw and/or treated lignosulfonate or similar products.

The aldehyde is preferably formaldehyde, for example in the form of paraformaldehyde, or acetaldehyde. The amide is preferably mainly urea or thiourea or their homologues or melamine, benzoguanamine or dicyandiamide or their homologues. The phenol is preferably phenol itself or resorcinol.

Among the sugars, sugar derivatives, their by-products and mixtures thereof, molasses, dextrose, glucose, fructose or sucrose or mixtures thereof such as corn syrup are most preferred. Among the starches, wheat starch, modifled starches, dextrin and the like are interesting as I~ are degradation products of starch and dextrin glues.

-2- Examples of raw lignosulfonates are black liquor and similar products, and examples of treated lignosulfonates are sodium, calcium and ammonium lignosulfonate.

The substitute of the invention preferably contains to 52 by weight of water.

The weight ratio of a) to b) and/or c) is preferably 0.1 to 50.0:1, most preferably 1.0 to 15.0:1.

The combination of a) with b) and/or c) presents a synergistic behaviour. If the single components are added alone to the resin they do not give good boards, but if they are added in combination, they exhibit an improvement in the board properties obtained. The substitute according to the present invention (calculated'as 100 solids) ooO. may substitute as much as 30 of the resin solids used.

o o 0o0 Said substitute is not added in quantities equal to the 0o 0 :o quantities substituted. It is added in quantities from o 50 to 90 of the amount of resin substituted (calculations S 20 referred to by weight and referring to all products as 0 100 solids).

o The substitute according to the present invention may therefore, because of its synergistic behaviour, substitute the resin in quantities from 110 up to 200 of its cc own weight. When added to lower amounts e.g. up to 15 there is a considerable increase in the properties of the end product. When added to higher levels, i.e. up to 30 no difference is imparted to the properties of the end product but the free formaldehyde is considerably reduced and the amount of resin saved is considerably increased.

Bonding is effected by curing the resin mixture at 3 elevated temperatures and pressures according to the methods well known in the art. The substitute may be used in all types of products where amino and phenolic resins are used for bonding lignocellulosic products, whether these are wood particles for particleboard production using a flat press, or a calender or wood veneers such as in plywood production.

It is very interesting to note that the product has also good tack. This property otherwise called "green strength" is desired in some types of particleboard plants, specially the plants with multi opening press and in plywood factories, specially those having a pre-press.

The quality of boards produced was controlled weekly for a period of six months and no reduction in the properaO ties was observed. This proves that no polymer degradation occurs and that the ageing properties of the boards are como 0 parable to the ones normally produced.

00 0 0 o on o o 20 The substitute of the invention can be prepared by o° 0o0. plain mixing of the components. In order to obtain an acceptable shelf-life of the substitute, a base is preferably added 'o to adjust the pH to a value in the range of 6 to 14.

o0 a1 0 00 25 Substitutes so far known in the art to substitute o 0 o 0oo resin have not succeeded in substituting such high levels of resin by using lower amounts of the substitute and reducing simultaneously the free formaldehyde of the boards, without 0 0 imparting any loss in bonding strength, without requiring any extra steps in the production, without changing the curing rate of the production, without causing any problems to the boilers when burning particleboard sander dust or edges from cutting saws and without reducing the tack of the resin mixture.

II In particular, the known substituents are lignosulfonates, sodium chloride or mixtures of formaldehyde with urea and sodium chloride. It is well known that lignosulfonates may not be used for quantities higher than 10 otherwise, board properties will be reduced.

0 0 0a 0 o o o o 0 0 o o0 00 00 0 o o 00 0oo 0 0 o o o t C Ct It is also known that the addition of hali-de salt alone succeeds in substituting part of the resin with the following limitations: -High substitutions, higher than 6 to 8 may not be obtained, otherwise the board properties will deteriorate.

-Substitution is obtained in ratios 1:1, while in the case of the substitute according to the present invention it is 1.1 to 2.0:1.

-When particleboard sander dust or edges from cutting saws are burnt in boilers, the latter are'plugged within a few hours.

-Tack is reduced when sodium chloride is added to the resin mixtures.

When mixtures of sodium chloride with urea and formaldehyde are used the following shortcomings are present -The presence of salt in the mixture causes severe problems in the boilers when sander dust or cutting saw edges of boards are burnt. That is caused because the presence of salt reduces the melting point of the mixture and as a result a molten mass deposits in the boiler forming a glass like deposit which adheres on the boiler thus plugging it.

-The other shortcoming of this product is the fact that tack is severely reduced, thus making it difficult to use in the plywood industry where there is a pre-press and in particleboard plants where a multi opening press is present requiring green strength of the mat.

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t t C c 5 The product according to the present invention overcomes all of the above shortcomings.

The substitute according to the present invention provides yet another advantage. Apart from substituting up to 30 of the resin by adding only 50 to 90 of the resin solids substituted, and reducing the free formaldehyde of boards, it reduces also the free formaldehyde in the production hall where workers are exposed to formaldehyde 0fumes.

St t s« The following Examples illustrate the invention o and are not intended as limitations. In the Examples, o 0 0o samples 0, 1 and 2 of Examples 1 and 2, and sample 0 of 0 Q o oo" each of Examples 3 to 9 represent the prior art/comparative Examples.

gout, Example 1 0 4 0000 0 0 0oo Three samples were prepared according to the fol- 0 "a lowing formulations Sample No. 1 2 3 parts by weight Formaldehyde 100 185 133 S" Urea 100 370 266 Molasses 100 555 156 Water 445 445 445 1000 1000 1000 The above mentioned samples were prepared by plain mixing at room temperature until the solids were completely dissolved, The pH of the final products was adjusted to to Glue formulations were then prepared as follows 7 1 i 6 Glue formutalation No. 0 1 2 parts by weight Urea formaldehyde resin solids) SWater Sample 1 Sample 2 Sample 3 Ammonium chloride (20%) 108.9 13.8 81.7 13.8 27.2 81.7 3.3.8 81.7 13.8 2 7.1 7.1 7.2 27.2 7.1 7.1 r i" i; No. 0: Glue formulation is the blank and does not include any of the above mentioned samples.

No. 1: Glue formulation includes sample 1, whereby only formaldehyde and urea are included.

No. 2: Glue formulation includes sample 2 whereby only molasses are included.

No. 3: Glue formulation includes sample 3 whereby all three ingredients are added, namely, formaldehyde, urea and molasses. Sample 3 represents the product according to the present invention.

These glue formulations were used separately to spray a constant quantity of dried wood chips.

The sprayed wood chips were then formed into a mat having a normal thickness of 16 mm. These mats were then introduced into a hot press and boards were pressed at the following conditions Press temperature 200 °C Press time 9 sec/mm 2 Pressure 33 kp/cm Boards were then tested and the results are reported in the following table.

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7 Glue formulation No. 0 1 2 3 Density (kg/m 3 582 591 583 582 Thickness (mm) 15.4 15.2 15.5 15.4 Internal bond (kg/cm 2 7.1 6.5 5.0 7.2 2 hrs thickness swelling 11.1 11.3 17.5 12.1 24 hrs thickness swelling 20.3 22.5 30.3 22.3 Free formaldehyde (mg/100 g dry board) 21.1 18.3 21.8 18.7 Moisture content 5.5 5.0 5.3 It can be noticed from the above mentioned table that while all three samples reduce the free formaldehyde of boards, only sample 3 including the components according to the present invention gives boards equivalent to the blank, without deterioration of the board properties.

00 a t Example 2 4 St 9 This example proves the synergistic behaviour o existing between formaldehyde, urea and lignosulfonates.

S S6t, For this purpose the following samples were prepared SSample No.' 1 2 3 parts by weight Formaldehyde (100 185 133 SUrea (100 370 266 Calcium lignosulfonate (100 555 156 Water 445 445 445 1000 1000 1000 The above mentioned samples were prepared by plain mixing at room temperature until the solids were completely dissolved. The pH of the final products was adjusted to to i

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t **e 8 Glue formulations were then prepared as Glue formulation No. 0 1 2 parts by weight folloNrT 3 Urea formaldehyde resin (65 solids) Water Sample 1 Sample 2 Sample 3 Ammonium chloride (20%) 108.9 81.7 13.8 33.8 27.2 81.7 13.8 27.2 81.7 13.8 r- 27.2 7.1 7.1 00 0 00 00 00 0 0 0 .o 0 00 06 00 0 0 0 ab 51 5 51 8 These glue formulations were used separately to spray a constant quantity of dried wood chips.

The sprayed wood chips were then formed into a mat having a nominal thickness of 16 mm. These mats were then introduced into a hot press and boards were pressed at the following conditions Press temperature 200 T; Press time 9 sec/mm Pressure 33 kp/cm 2 Boards were then tested and the in the following table 25 Glue formulation No. 0 1 Density (kg/m 3 580 591 Thickhess (mm) 15.5 15.2 Internal bond (kg/cm 2 7.0 6.3 2 hrs thickness swelling 11.2 11.3 24 hrs thickness swelling 20.6 22.5 Free formaldehyde (mg/100 g dry board) 23.9 19.8 Moisture content 5.8 5.0 results are reported 2 590 15.0 5.4 17.8 29.5 18.5 4.5 3 58I 15.1 6.9 11.8 23.8 17.8 4.8 9 -11 9 It will be noticed from the above mentioned figures that boards produced with plain lignosulfonates, sample 2, have the worst results. Boards obtained with all three components according to our present invention, sample 3, have the best results. Actually boards of sample 3 are equivalent to the blank, 0, which is the resin mixture without any substitute, while giving at the same time a reduction in the free formaldehyde of the boards.

Example 3 In this example two samples are illustrated whereby the ratio of formaldehyde to urea is different from the one used in the previous examples. Also the weight ratio between components a) andb) is different from the 'one of examples 1 and 2.

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co"o The following samples were prepared 00 .o Sample No. 1 2 00o o o 0 "20 parts by weight as Formaldehyde (100 133 133 Urea (100 177 177 SMolasses (100 156 S Dextrin glue (100 30 O' 25 Calcium iignosulfonate (100 186 S"f Water 504 504 1000 1000 S* The above mentioned samples were prepared by plain mixing at room temperature until the solids were completely dissolved. The pH of the final products was adjusted to to Glue formulations were then prepared as follows Su formLation No s Glue formuiafcioni No.

10 parts by weight Urea formaldehyde resin (6'55 solids) Water Sample 1 Sample 2 Ammonium chloride (20%) 108.9 87.1 13,8 1.3.8 21.8 87.1 13.8 7.1 21.8 7.1 7.1 These glue formulations were used separately to spray a constant quantity of dried wood chips.

The sprayed wood chips were then formed into a mat having a nominal thickness of 16 mm. These mats were then introduced into a hot press and boards were pressed at the following conditions Press temperature 200 °C Press time 9 sec/mm 2Pressure 33 kp/c 2 Pressure 33 kp/cm o 00 0 0 0 0o 00 0 00 00 0 o oo ol 0 0 0 0 a t 0 0S 0 0 0 o o 0 t 0 o 0 00 IC 0 0 0 Q 060 0- 0 00 0 o0 so o0 Boards were then tested and the in the following table Glue formulation No. 0 Density (kg/m 3 577 25 Thickness (mm) 15,.1 2 Internal bond (kg/cm 8.1 2 hrs thickness swelling .10.5 24 hrs thickness swelling 19.9 Free formaldehyde 30 (mg 100 g dry board) 46.6 Moisture content 5.9 results are reported 1 595 15.4 8.7 10.0 19.3 39.2 5.3 2 587 15.,2 8.9 9.8 18,7 345.0 It can be noticed from the above mentioned table that samples 1 and 2 including the substitute according to the present invention give boards equivalent to the blank, t; s 11 sample 0, while giving a significant free formaldehyde reduction and resin saving.

,i Example 4 This is a laboratory test for p. ywood using a phenolic resin.

The following samples were prepared: Sample No.

parts by weight Phenol (100%) 180 Formaldehyde (100%) 80 Molasses (100%) 120 Ammonium lignosulfonate (100%) 200 Water '420 200 100 180 520 1000 Total 1000 a oo 0 0 0 0 00 0 0 0 ct t r

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The samples were prepared by plain mixing at room temperature until the solids were completely dissolved.

The pH of the final products was brought to 10.0 by means of addition of sodium hydroxide.

These samples were used in a glue formulation as follows: Glue formulation No.

Phenol formaldehyde glue (100%) 100 Hardener (calcium carbonate: wheat flour weight ratio 50:50) 60 Water 107 Sample 1 1 parts by weight 30.77 c 't C s 2 f I 9 12 Sample 2 Wheat flour 30.77 Total Viscosity (mPa.s) 267 1200 260.77 1300 270.77 1100 The above mentioned glue formulations were used to spread both sides of the core vnneer for 3 ply boards.

Boards were then introduced in a cold press where they were pressed under the following conditions: Press time Pressure 8 minutes 10 kp/cm 2 All boards gave very good tack properties.

They were then pressed in a hot press under the following conditions: 4 45

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4a *l s I o *i a 54 *4 20 Press temperature Press time Pressure 13000 3.5 minutes 12 kp/cm 2 These boards were tested as follows: They were immersed for 24 hours in water at 60C0.

After this they were introduced in water at 200C for one hour and then the knife test was carried out.

30 44 Results were as follows: 5* 54 4 4 Glue formulation No.

Grading 0 1 10/10 10/10 2 10/10

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2 U: 13 The knife test is carried out as follows: Plywood samples are placed in water under pressure for 30 minutes and then in vacuum for another minutes. Samples are then scraped with a knife on the surface until the top veneer comes off and the core shows up. The grading depends on the amount of fibers showing in the core after the top veneer was scraped off.

When gluing is satisfactory, the surface that appears after scraping with the knife must still be covered with fibers. When it is completely covered with fibers grading is 10 (excellent). As more clean spots appear and less fibers, grading is diminished. A grading of 8 is still satisfactory, ant it means th.at the surface is mainly covered with fibers with only a few clean spots .appearing. Lower grading is unsatisfactory.

Example 4 @4~ 448 4 34 4P 0 49 4 0.

"".30 4.4(9(9 Two samples were prepared according to the following formulations: Sample No. 1 2 parts by weight Formaldehyde (100%) Urea (100%) Melamine (100%) Molasses (100%) Ammonium lignosulfonate (100%) Water Total 100 140 100 1410 190 110 110 150 510 1000 450 1000 (9 ;iiii I .ir 14 The above mentioned samples were prepared by plain mixing at 25 to 300C until the solids were completely dissolved. The pH of the final products was adjusted to 8.5 to 10.0.

Glue formulations were then prepared as follows: Glue formulation No. 0 1 2 parts by weight Kauramin 535 (63% solids) 108 92 92 Hardener 14.8 14.8 14.8 Formic acid (20%) Paraffin emulsion Sample 1 Sample 2 Water 4 5.5 4 5.5 4 The Hardener solution was: hot water urea ammonium chloride Total 16 13 462 384 154 1000 CC C C te ii

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4 i 4 6* I 6 06 These glue formulations were used separately to spray a constant quantity of dried wood chips with 12% dry glue/ dry wood.

The sprayed wood chips were then formed into a mat having a normal thickness of 16 mm. These mats were then introduced into a hot press and boards were pressed at the following conditions: Press temperature Press time Pressure 2000C 10 sec/mm 35 kp/cm 2 0* 04 6 a W C 4.

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15 Boards were then tested and the results are reported in the following table.

Glue formulation No. 0 1 2 Density (kg/m 3 686 687 685 Thickness (mm) 15.9 15.7 15.7 Internal bond (kg/cm 2 6.6 6.5 6.4 2 hrs thickness swelling 3.2 3.2 2.9 24 hrs thickness swelling 9.2 9.0 V-100 (kg/cm 2 1.6 1.5 1.6 The V-100 test is carried out as follows: The samples to be tested are placed in water at 20 5°C. This water is warmed up in 1 to 2 hours to 1000C. The water temperature is kept at 1000C for 2 hours.

It is important that there is a space of at least 15 mm on all sides of every sample so as to make sure that water is freely introduced in the samples. The samples are then introduced for at least 1 hour in a refrigerao c tor at 2 5 0 C. Water is then allowed to drip and the S wet samples are tested again for internal bond.

t cc c SExample 6 c SThe following example will illustrate the fact that products according to our present invention may be produced by means of a variety of raw materials.

o Samples were prepared according to the followo 0o o" ing formulations:

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B -j i.r f r 16 Sample No. 1 2 parts by weight 350 Paraformaldehyde Precondensate 80% (1) Acetaldehyde 100 Urea 100% Sucrose 100% Molasses 100% Ammonium lignosulfate 100% Dextrin 100% Water 150 50 50 400 12 100 150 230 418 130 200 210 460 Precondensate containing 53 parts by weight of formaldehyde, 27 parts by weight of urea and 20 parts by weight of water The above mentioned samples were prepared by plain mixing until the solids were completely dissolved.

The pH of the final products was adjusted to 7.5 to Glue formulations were then prepared as follows:

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a t C SC C 4 t 4£ 0 CC 4 04 O 0i S, Glue formulation No.

Urea formaldehyde resin solids) Water Sample 1 Sample 2 Sample 3 Ammonium chloride (20%) 1 2 parts by weight 3 93 13.8 108.9 93 13.8 13.8 15.9 93 13.8 15.9 15.9 .1 7.1 7.1 7.1 7 These glue formulations were used separately to spray a constant quantity of dried of wood chips.

The sprayed wood chips were then formed into a mat having a normal thickness of 16 mm. These mats were 4_11__ 17 then introduced into a hot press and boards were pressed at the following conditions: Press temperature 200 0

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Press time 9 sec/mm Pressure 33 kp/cm 2 Boards were then tested and the results are reported in the following table: Glue formulation No. 0 1 2 3 Density (kg/m 3 600 610 590 580 Thickness (mm) 15.8 15.9 15.7 15.6 Internal bond (kg/cm 2 6.8 6.9 7.1 2 hrs thickness swelling 10.5 10.3 10.1 9.9 24 hrs thickness swelling 20.1 19.5 19.9 20.3 Free formaldehyde 22.3 18.0 16.2 17.1 Moisture content 5.7 5.3 5.5 5.6 Boards obtained with all glue formulations are equivalent.

S" Example 7 C f In this example four samples were prepared according to the following formulations: IC r

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18 Sample No.

Formaldehyde Resorcinol Thiourea Urea Benzoguanamine Dicyandiamide Wheat starch Dextrose Glucose Fructose Modified starch Corn syrup Molasses Black liquor Sodium lignosulfonate Water Total 1 100 50 i- 0 140 100 500 1000 2 parts by 100 150 100 500 1000 3 weight 100 70 4 100 50 150 500 1000 100 100 500 1000 2 0 Starch which has been hydrolysed to give a lower molecular weight and, therefore, a low viscosity The above mentioned samples were prepared by plain mixing at 40 to 50 0 C until the solids were completely dissolved. The pH of the final products was adjusted to 8.5 to 10.0.

Glue formulations were then prepared as follows: SC c o 19 Glue formulation No.

1 *2 3 parts by weight Urea formaldehyde resin 108.9 Water 13.8 Sample 1 Sample 2 Sample 3 Sample 4 Ammonium chloride 7.1 87.1 13.8 21.8 7.1 87.1 13.8 87.1 13.8 4 J7.1 13.8 21.8 7.1 21.8 21.8 These glue formulations were used separately to spray a constant quantity of dried wood chips.

The sprayed wood chips were mat having a nominal thickness of 16 then introduced into a hot press and at the following conditions: then formed into a mm. These mats were boards were pressed t cr V; z Press temperature Press time Pressure 2000C 9 sec/mm 33 kp/cm 2 Boards were then tested and the results are reported in the following table: Glue formulation No.

Density (kg/m) E Thickness (mm) Internal bond (kg/cm) So", 2 hrs thickn. swelling 24 hrs thickn. swelling Free formaldehyde (mg/100 g dry board) Moisture content 0 625 15.9 7.0 12.5 22.5 28.8 6.1 1 617 15.8 6.9 12.1 20.7 22.5 5.7 2 633 16.0 7.1 13.6 24.7 21.7 5.9 3 631 16.2 7.2 13.1 24.0 23.0 5.9 4 628 16.0 6.8 12.6 20.9 21.9 6.2 20 It can be noticed from the above mentioned table that samples 1 to 4 including the substitute according to the present invention give boards equivalent to the blank, sample 0, while giving a significant free formaldehyde reduction and resin saving.

Example 8 Three samples were prepared according to the following formulations: Sample No. 1 2 3 Formaldehyde 100% Urea 100% Sucrose 100% Molasses 100% Calcium lignosulfonate (100%) Water 13 36 1 49 100 parts by weight 5 135 135 5 365 365 n 0 0 490 1000 490 1000 C C t C C Co C C C? C C CC Cm CC CC Total The above mentioned samples were prepared by plain mixing at 25 to 30 0 C until the solids were completely dissolved. The pH of the final products was adjusted to 8.5 to 10.0.

Glue formulations were then prepared as follows: i-i--i 2g **e 21 Glue formulation No.

Urea formaldehyde resin (65% solids) Water Sample 1 Sample 2 Sample 3 Ammonium chloride solution in water) 0 1 2 parts by weight 108.9 95.9 95.9 3 95.9 13.8 13.8 13.8 13 13.8 13 7.1 13 .1 7.1 7.1 These glue formulations were used separately to spray a constant quantity of dried wood chips.

The sprayed wood chips were then formed into a mat having a nominal thickness of 16 mm. These mats were then introduced into a hot press and boards were pressed at the following conditions: Press temperature 2000C Press time 8 sec/mm 20 Pressure 35 kp/cm 2 0 00 0 0 a oo 0 00 0 00 0 a t o 0 t 0 0 0 e 0 00 Boards were then tested ported in the following table: and the results are re- 25 Glue formulation No.

Density (kg/m 3 Thickness (mm) Internal Bond (kg/cm 2 2 hrs thickness swelling 24 hrs thickness swelling Free formaldehyde (nig/lO0 g dry board) Moisture content 0 575 15.

8.3 10.3 20.2 60.5 1 582 15.3 8.7 10.8 21.3 39.8 2 579 15.5 8.9 10.6 20.9 41.3 3 601 11 .1 21.9 38.1 0 *0 *s i 6.0 7.1 6 .6 m m ~L-Il1~--CI I 22 Boards obtained with all glue formulations are equivalent. Those however that include the substitute according to the present invention have lower free formaldehyde.

Example 9 Three samples were prepared according to the following formulations: Sample No.

Formaldehyde.100% Urea 10C' Sucrose 100% Molasses 100% Calcium lignosulfonate (100%) W.ater Total 1 2 3 parts by weight 85 85 0OC 400 400 32.3 52.3 32.3 482.7 482.7 482.7 1000 1000 1000 0 00 0 C 0 0 0 0 ao t c t 1 The above mentioned samples were prepared by plain mixing at 25 to 300C until the solids were completely dissolved. The pH of the final products was adjusted to 8.5 to 10.0.

Glue formulations were then prepared as follows: cc 0c c e ".4 23 Glue formulation No.

Urea formaldehyde resin (65% solids) Water Sample 1 Sample 2 Sample 3 Ammonium chloride (20% solution in water) par 108.9 81 13.8 7.1 13 27 2 ts by-weight .7 81.7 .8 13.8 .2 S 27.2' .1 7.1 3 81.7 13.8 27.2 7.1 7 These glue formulations were used separately to spray a constant quantity of dried wood chips.

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Ct C t The sprayed wood chips were mat having a nominal thickness of 16 then introduced into a hot press and at the following conditions: Press temperature 2000C Press time 8 sec/mm Pressure 35 kp/cm 2 Boards were then tested and ported in the following table: then formed into a mm. These mats were boards were pressed the results are re- (t *t Cc Glue formulation No.

Density (kg/m 3 Thickness (mm) Internal bond (kg/cm 2 2 hrs. thickness swelling 24 hrs. thickness swelling Free formaldehyde (mg/100 g dry board) Moisture content 0 610 15.9 7.9 9.8 20.1 40. 1 1 590 15.7 8 .1 10.2 21.3 15.3 2 597 15.6 8.3 10.5 20.9 17.1 3 615 15.9 8.4 10.9 21.8 16.3 7.9 7.1 7.6 24 Boards obtained with all glue formulations are equivalent. Those however that include the substitute according to the present invention have a very big formaldehyde reduction and resin cost saving.

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Claims (12)

1. A substitute for replacing up to 30% by weight of amino and phenolic resins in the polycondensation of such resins based on formaldehyde for 10 bonding water penetrable cellulosic particles, the 4o: substitute comprising an aqueous solution of l et a) either an aldehyde together with an amide and/or together with a phenol, or a non-resinous condensation product of formaldehyde and urea, and either or both of b) a sugar or a sugar derivative or their by-products or a starch or its degradation products or a mixture theredf, or c) a raw and/or treated lignosulfonate.

2. A substitute according to claim 1, character- ized in that it contains 40 to 52% by weight of water.

3. A substitute according to claim I or 2, characterized in that the weight ratio of a) to b) and/or c) is 0.1 to 50.0:1.

4. A substitute according to claim 3, character- ized in that the weight ratio of a) to b) and/or c) is 1.0 to 15.0:1. A substitute according to one of claims 1 to 4, characterized in that the aldehyde is formaldehyde or acetaldehyde. 26

6. A substitute characterized in that melamine, benzoguanamine

7. A substitute characterized in that resorcinol. according to one of claims 1 to the amide is urea, thiourea, or dicyandiamide. according to one of claims 1 to the phenol is phenol itself or bI I. II 44F~ 6 440

8. A substitute according to one of claims 1 to 7, characterized in that component b) is molasses, dex- trose, glucose, fructose, sucrose, corn syrup, wheat starch,modified starch or dextrin glue.

9. A substitute according to one of claims 1 to 8, characterized in that component c) is ammonium, sodi- um or calcium lignosulfonate or black liquor. C I 0 C II Fr C; I 4* 4 4' 441 27 A substitute for amino or phenolic resins according to claim 1 and substantially as hereinbefore described with reference to the Examples.

11. A process for the production of a resin composition for bonding water penetrable cellulosic particles, the process comprising providing an amino or phenolic resin polycondensable on a formaldehyde basis and admixing therewith, in substitution of up to 30 weight percent (calculated as 100% solids) relative to a nominal resin content, a substitute as defined in any preceding claim, the amount of substitute used being 0.5 to 0.9 times the weight of the difference between the actual resin content and the nominal resin content.

12. A resin composition for bonding water penetrable cellulosic particles produced by the process of claim 11.

13. An article comprising water soluble cellulosic particles bonded by the resin composition of claim 12. rItr 4. c *lI I

14.1~r 4~ I tP t t I I DATED this 22nd day of August 1990. ENIGMA N.V. By Its Patent Attorneys DAVIES COLLISON 900823,imndat050,a:\73788enLres,27