IT8447647A1 - FORMALDEHYDE BINDER AND PROCEDURE FOR PREPARING IT AND OBTAINING WOOD PANELS WITH IT. - Google Patents

Description

DOCUMENTATION

BOUND

SIB . 84684

47647 A84 Case 4B

DESCRIPTION of the industrial invention entitled: "FORMALDEHYDE BINDER AND PROCEDURE FOR PREPARING IT AND OBTAINING WOOD PANELS WITH IT"

of the Netherlands Antilles company: ENIGMA N.V.

based in -CURA^AO (Netherlands Antilles) -

SUMMARY

A formaldehyde binder is described for use in lignocellulosic sheet materials such as particleboard, plywood, or blockboard, in which a formaldehyde-based adhesive is employed.

The binder comprises an organic hydroxy compound and an amide.

DESCRIPTION

Boards such as particleboard, grayboard, and similar materials are made from lignocellulosic materials using adhesives. The preferred adhesives (or glues) are formaldehyde-based, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde, and resorcinol-formaldehyde resins, or mixtures thereof. It is well known that boards made using these adhesives have a formaldehyde odor that is both harmful and unpleasant. Formaldehyde is released both during the production of these boards and during their storage and final use.

Many methods have been proposed to prevent formaldehyde emissions, but all are ineffective, reduce the properties of the boards, or require complicated application processes. Some of these processes involve spraying or extensively coating the hot boards emerging from the press with various solutions, such as urea solutions and/or ammonia or ammonium salts. In general, these methods are undesirable for industrial applications because they require additional processing steps and are inefficient.

Other methods involve the use of very complicated mixtures of a large number of components, some of which are natural glues. These products are also not very efficient. One obstacle is the fact that the properties of natural products are not consistent.

Another way to reduce free formaldehyde content involves using an aqueous suspension of urea agglomerates coated with a special wax. This method also requires a separate feed line because the product is not added to the adhesive formulation itself.

It is an object of the present invention to provide A.

a formaldehyde binder that effectively reduces formaldehyde odor without reducing the properties of the board, without changing the reactivity of adhesive formulations, and without requiring any additional steps in the production of particleboard, plywood, or blockboard.

The present invention provides a formaldehyde binder for use in boards prepared from 1-cellulosic materials using formaldehyde-based adhesives which consists of a solution in water of a) at least one organic hydroxy compound with the exception of monovalent aliphatic C 1 -4 alcohols and

b) at least one amide.

The formaldehyde binder may also contain (c) an organic compound that acts as a solvent for (a) and (b) and also reacts with formaldehyde, and (d) a water-soluble inorganic compound. The organic compound (c) is preferably a monovalent aliphatic C^_4 alcohol. The inorganic compound (d) is preferably a halide salt. Although the individual components are not water-soluble, they can dissolve in water if a mixture of them is heated in water to 70°C.

Preferably, the organic hydroxy compounds /^component (a)_7 are soluble in water or in lower monovalent aliphatic alcohols. Examples of such preferred hydroxy compounds are the divalent, trivalent and pentavalent alcohols containing up to

6 carbon atoms, monosaccharides containing up to 6 carbon atoms, disaccharides containing up to 12 carbon atoms, and polysaccharides having an Ostwald viscosity of up to 200 mPa s at 25°C and a concentration corresponding to a refraction of 37%. Other examples of preferred hydroxy compounds are aromatic alcohols and phenols, which are preferably used alone or in combination with one or more of the above-mentioned dihydric, trihydric, or pentahydric alcohols, or monosaccharides, disaccharides, or polysaccharides. Phenols and aromatic alcohols may be monohydric or polyhydric phenols and monohydric or polyhydric aromatic alcohols containing a benzene ring.

Specific examples of suitable organic hydroxy compounds are monoethylene glycol, diethylene glycol, glycerin, pentaerythritol, fructose, mannose, sorbitol, dextrose, sucrose, maltose, lactose, dextrin, phenol, resorcinol, hydroquinone, and the like.

Preferably, the amides /_ component (b)_/ used in the formaldehyde binder of the present invention are equally soluble in water or in lower monovalent aliphatic alcohols. Particularly preferred are aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

Suitable examples of amides are urea, thiourea, formamide, acetamide, benzamide, 6-acetamide, succinamide, malonamide and the like.

If desired, to enhance solubility, the formaldehyde binder of the present invention may additionally contain additives /_ component (c)_/ which are lower monovalent aliphatic alcohols such as methanol, ethanol, isopropanol and the like.

A cheaper and more efficient formaldehyde binder is obtained if inorganic compounds /_component(d)_/ are added which are preferably halide salts, still preferably halides of alkali metals or alkaline* earth metals such as sodium chloride, potassium chloride and calcium chloride.

The ratio of organic hydroxy compound ^component (a) to component (c), if present_/ and inorganic compound /^component (d), if present _7 to amide /^component (t?)_/ is preferably 10:100 up to 400:100, particularly 10:100 up to 200:100 by weight. The formaldehyde binder of the present invention

It can be added to conventional glue formulations in quantities ranging from 1 to 10%, preferably 3 to 7%, of formaldehyde binder solids, based on the weight of the liquid resin containing 65% resin solids by weight.

The formaldehyde binder of the present invention may contain from 20 to 80% by weight, preferably from 50 to 70% by weight, of the active ingredients /^components (a) and (b) and components (c) and, or

(d) , if present_T. The water content of the formaldehyde binder depends on the solubility of the active ingredients and the amount of water that can be tolerated in the glue formulations.

The formaldehyde binder of the present invention can be produced simply by adding the active ingredients and water to a mixer and stirring until the active ingredients have dissolved. This can be done at room temperature or at elevated temperatures up to 70°C.

The formaldehyde binder of the present invention can be used whenever boards are prepared from cellulosic materials using formaldehyde-based adhesives, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde or resorcinol-formaldehyde resins or mixtures thereof.

When to use formaldehyde binder

of the present invention, it is possible to produce boards containing in reality less than 10 mg of free formaldehyde per 100 g of the dry board, as determined by the F.E.S.Y.P. (Fed?ration Europ?enne des Syndicats des Fabricants de Panneaux de Particules) perforator method No. EN 120.

The extent of free formaldehyde reduction depends on many factors and can therefore vary widely. If the free formaldehyde emission

If the free formaldehyde emission is high (greater than 50 mg of formaldehyde per 100 g of dry table), the reduction can be as high as 60 to 857%. If the free formaldehyde emission is relatively low, i.e. 20 to 50 mg of free formaldehyde per 100 g of dry table, the maximum reduction is usually 50 to 60%. The amount of reduction achieved also depends on the amount of formaldehyde binder used: the more formaldehyde binder is used, the lower the amount of free formaldehyde.

When the active ingredients of the formaldehyde binder are used in combination with each other, the reduction of free formaldehyde is surprisingly much higher than the sum of the effects of the separate components and they have no adverse effect on the reactivity of the glue formulation or the properties of the boards.

The following examples illustrate the present invention. Parts and percentages are by weight.

Example 1

In this example, the organic compound containing hydroxyl groups is glycerol and the amide is urea.

The synergistic behavior is illustrated here

of these two compounds. Various glue formulations are prepared and each is subsequently used to produce particleboard.

The control does not contain any of the components of the formaldehyde binder according to the present invention. Sample 1 contains both glycerin and urea, Sample 2 contains only glycerin, and Sample 3 contains only urea.

It should be noted from the tables below that glycerin, when used alone (Sample 2), is a very effective formaldehyde binder but urea (Sample 3) gives poorer formaldehyde reduction and lower mechanical and water resistance values, however, when urea is used in combination with glycerin (Sample 1), it gives values that are equivalent to those of glycerin alone.

It is therefore possible to use a cheaper and less effective product (urea) and make it react as effectively as a more expensive and more effective product (glycerin). Effectiveness refers to the ability to absorb formaldehyde and maintain good mechanical properties and water resistance without changing the reactivity of the glue formulation and without the need for any special equipment for its use. The formaldehyde reduction in this case is actually 46%.

The formulations of the various samples used are as follows:

1st:parts _2nd;parts 3rd parts by weight by weight by weight glycerin (100%) 270 590

Urea (100%) 320 - 590 water 410 410 410

1000 1000 1000 % solids 59 59 59 The glue formulations used are as follows:

Control ^

grams grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1.27:1) 3077 3077 3077 3077 Hardener (ammonium

chloride 15%) 400 400 400 400 paraffin emulsion 50% 250 250 250 250 Ammonium 25?Baum? 5 5 5 5 sample 1 308

sample 2 308 sample 3 308 water 268

total 4000 4040 4040 4040 gelling time in seconds 68 68 71 62

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Controls) 1

Density (kg/cm^) 683 669 663 657 Flexural strength 19.9 18.1 17.3 16.3 (N/mm^)

Tensile strength 0.73 0.72 0.71 0.63 (N/mm2)

Swelling of

thickness in 2 hours (?) 5.2 V 5.4 Swelling of

thickness in 24 hours (*> 51.4 49.9 47.4 53.1

15.8 8.5 8.7 H ,7 free formaldehyde

(mg/100 g of dry table)

Example 2

This is another example illustrating the synergistic behavior of glycerin and urea in reducing free formaldehyde in particleboard while maintaining the mechanical properties of the boards and also their water resistance.

The control does not contain any of the components of the formaldehyde binder according to the present invention. Sample 1 contains both components of the formaldehyde binder according to the present invention, and Sample 2 contains only one of the two components (the more effective of the two components).

It is to be noted here again that only sample 1 gives free formaldehyde which is below

10 mg/100 g of dry table (which is the desired level for class El) and is the only one with absolutely equivalent mechanical properties and water resistance. The formaldehyde reduction is actually 34%.

The formulations of the various samples used are as follows:

parts by weight parts by weight glycerin (1007o) 128 128 urea (100%) 424

water 448 872

1000 1000

% solids 55.2 12.8 The glue formulations used are as follows:

I'm checking the 2

grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1.27:1) 3077 3077 3077 Hardener (ammonium

chloride 15%) 400 400 400 paraffin emulsion 50% 250 250 250 Ammonium 25?Baum? 5 5 5 sample 1 268

sample 2 268

water 268

total 4000 4000 4000

gelling time in seconds 66 67 69

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm2. The produced boards measure 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 Density (kg/cm^) 685 684 687 Flexural strength (N/mm^) 20.7 20.6 19.4 Tensile strength (N/mm^) 0.74 0.73 0.67 Thickness swelling

in 2 hours (%) 11.0 7.9 8.6 Absorption in 24 hours (%) 23.5 23.2 23.7 free formaldehyde 14.3 9.5 12.3 (mg/100 g of dry tablet)

Example 3

This example illustrates the effectiveness of monoethylene glycol together with urea as a formaldehyde binder.

Two formulations are prepared: the control without any of the formaldehyde binder ingredients of the present invention and Sample 1 which contains both monoethylene glycol and urea.

Boards are produced from <? these: two glue formulations and it is also shown here that with the formaldehyde binder according to the present invention, boards classified as E 2 (control) are obtained with a urea-formaldehyde resin, which normally gives boards classified as E 1 (sample 1). The formaldehyde reduction in this case is 37%.

The formulation of sample 1 used is as follows:

Sample 1 parts by weight monoethylene glycol 100% 360

urea 1007o 365 water 275_

1000

% solids 72.5

The glue formulations used are as follows:

Control 1 _ grams grams urea-formaldehyde resin 65% 3077 3077 (molar ratio F:U = 1.27:1)

hardener 400 400 (ammonium chloride 15%)

50% paraffin emulsion 250 250 ammonia 25?Baum? 5 5 sample 1 - 268 water 268

total 4000 4000 gelling time in seconds 66 60 - JLb -

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 mm.

The results obtained are reported in the following table and are average values.

Control l Density (kg/cm-*) 685 684 Flexural strength (N/mm^) 20.7 20.2 Tensile strength (N/mm2) 0.74 0.74 Thickness swelling

in 2 hours (%) 11.0 8.6 Absorption in 24 hours (%) 23.5 22.6 free formaldehyde 14 3 9.0 (mg/100 g of dry table)

Example 4

This example illustrates the synergistic behavior of monoethylene glycol and urea.

Tables are prepared from three different formulations: the control in which none of the ingredients of the formaldehyde binder of the present invention are used, sample 1 in which both ingredients of the formaldehyde binder of the present invention are used, and sample 2 in which only one ingredient is used.

It is obvious from the results obtained and reported below that sample 1 containing both ingredients is much more effective than sample 2 containing only one ingredient (the more effective of the two ingredients).

The formaldehyde reduction obtained in this case is 32%.

The formulations of the various samples used are as follows:

1 2 parts by weight parts by weight monoethylene glycol 100% 230 580 urea 100% 350

water 420 420

1000 1000 % solids 58 58 The glue formulations used are as follows: Control ^ 2

grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1,27:1) 3077 3077 3077

Hardener (ammonium

chloride 15%) 400 400 400

paraffin emulsion 50% 250 250 250

Ammonium 25?Baum? 5 5 5

sample 1 268

sample 2 268

water 268

total 4000 4000 4000

gelling time- 70 l? 76

cation in seconds

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 mm.

The results obtained are reported in the following table and are average values.

Control_ 1_ Density (kg/m^) 688 688 687 Flexural strength (N/mm^) 17.6 17.6 17.5 Tensile strength (N/mm^) 0.55 0.60 0.56 Thickness swelling

in 2 hours (7>) 6.7 4.9 4.7 Absorption in 24 hours (%>) 20.1 20.1 19.5 free formaldehyde 15.0 10.3 12.3 (mg/100 g of dry table)

Example 5

This example illustrates the use of a resin with a different molar ratio as well as various addition levels of the formaldehyde binder itself.

The formaldehyde binder used has the following formulation:

parts by weight glycerin 100% 270

urea 100% 318 water 412

1000

% solids 58.8 - lu ?

The glue formulations used in the various

samples are as follows:

Control 1 2 3 grams grams grams grams Urea-formaldehyde resin 65% 3077 3077 3077 3077 (molar ratio F:U=1.4:1)

Hardener (ammonium chloride 293 380 380 380

15% )

50% paraffin emulsion 250 250 250 250 ammonia 25?Baum? 5 5 5 5 formaldehyde binder 154 215 375 water 375 134 73 total 4000 4000 4000 4087 gel time in sec. 73 73 72 75 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200?C and the pressure is 35 kg/cm^. The dimensions of the boards produced are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 3 Density (kg/m^) 680 687 685 688

flexural strength 22.0 22.5 22.3 21.6 (N/mm^)

tensile strength 0.61 0.63 0.66 0.64 (N/mm^)

swelling of thickness in

2 hours (%) 10.1 9.3 8.8 9.5 thickness swelling

in 24 hours (%) 20.6 21.8 21.0 21.5 free formaldehyde 22.2 13.0 10.1 9.5 (mg/100 of dry tablet)

It should be noted that the mechanical properties and water resistance of the boards are equivalent and

the reduction of formaldehyde is 41% in the case of sample 1, 55% in the case of sample 2 and 57% in the case of sample 3.

Example 6

This example illustrates six different types of polyols, two different types of amides, one additive, and a variation in the ratio of alcohol to covering amide |a range from 57.5/100 to 385/100.

The various types of formaldehyde binder used are as follows:

1 2 3 4

dextrose 230

diethylene glycol 330

monoethylene glycol 260 110 glycerin 500

sucrose 110 sorbitol 140

methanol 200 140 80 ho N5 urea 400 300 130 350 330 thiourea 170

water 370 . 370 370 370 370 370

Total 1000 1000 1000 1000 1000 1000

7? of solids 63 63 63 63 63 63

Weight ratio of

57.5/100 110/100 270/100 385/100 80/100 91/100 alcohol/amide

All above values are parts by weight.

The glue formulations used in the various samples are as follows:

1 2 3 4 5 6

Control grams grams granimi- grams: grams grams Urea-formaldehyde resin grams

657o (molar ratio F:U- 3077 3077 3077 3077 3077 3077 3077 1.27:1)

Hardener (ammonium chloride, 15% solution) 400 500 500 500 500 500 500

50% paraffin emulsion 250 250 250 250 250 250 250

I

Ammonia 25? Baum? CO 5 ?P*

I

formaldehyde binder

sample 1 307

sample 2 307

sample 3 307

sample 4 307

sample 5 307

sample 6 307

water 268

total 4000 4134 4134 4134 4134 4134 4134 4134

65 66 65 67 66 62 69 gelling time in sec.

Single layer boards are prepared

in the laboratory by spraying each of these formulations on 25 kg of wood chips.

The boards are pressed for 10, 9, and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the boards produced are 40 x 56 cm. The results obtained are shown in the following table and are average values.

Control 1

Density? (kg/m^) 688 689 687 685 690 685 692

flexural strength (N/mm2) 19.6 19.5 18.3 19.5 20 f1 19.3 19.4 tensile strength (N/mm2) 0.71 0.69 0.67 0.73 0.74 0.72 0.70 thickness swelling in 7.0 6.5 5.0 5.5 6.1 6.5 6.2

2 hours (7o) 19.7

thickness swelling in 19.3 20.0 19 .8 19.5 20.1 19.9

ro 24 hours (%)

(mg/100 g of

formaldehyde free dry table.), 16.1 8.9 8.6 11.0 9.0 9.8 8.5 formaldehyde reduction % 45 47 32 44 39 47

The above results demonstrate that

all samples used have equivalent values

to the control and that the reduction of formaldehyde is of the order of 32 to 47%.

Example 7

In this example, three different types of organic compounds containing . hydroxyl groups are exemplified by dextrin, phenol, and resorcinol.

A monohydric alcohol that functions as a different additive than methanol is also illustrated, namely ethyl alcohol.

The various types of formaldehyde binder used

they are as follows:

3_ 4 monoethylene glycol 230

dextrin 140

phenol 130 resorcinol 130 methanol 140 130 130 ethanol 80

urea 350 350 370 370 water 340 370 370 370

1000 1000 1000 1000 μL of solids 66 63 63 63 All values above are parts by weight. Formaldehyde binder samples are used in this example to replace a portion of the used resin.

What glue formulations are actually used?

they are as follows:

Control ^ 2 3 - A grams grams grams grams grams Urea-formaldehyde resin?

3077 2770 2770 2770 2770 657o(molar ratio F:U=

1,27:1)

Hardener (ammonium chloride, 15% solution) 400 500 400 450 400 paraffin emulsion 507, 250 250 250 250 250 Ammonia 25? Baum? 5

formaldehyde binder

sample 1 307

sample 2 307

sample 3 307 sample 4 307

water 2O8

total .40.00 3827 3727 3777 3727 gelling time

in sec. 65 64 62 63 63 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10.9 and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the pressed boards are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 3 the

Density? (kg/m^) 702 698 695 705 710

flexural strength (N/mm2) 20.1 19.5 19.7 20.0 20.8 tensile strength (N/moi^) 0.75 0.70 0.75 0.73 0.72 thickness swelling in 7.1 6.8 ?6?5 6.3 6.6 2 hours (7.) _

thickness swelling in 20.3 21.5 21.3 21.8 21.3 24 hours (%)

free formaldehyde 13.1 9.6 5.2 8.2 10 formaldehyde reduction % --P7 30 37 24 The above results demonstrate

that all samples have values that are equivalent to the control sample containing no formaldehyde binder even though the latter replaces an equivalent amount of urea-formaldehyde resin in the formulation. The formaldehyde reduction in this example varies from 24 to 37%.

Example 8

In this example a type of formaldehyde binder is used and the resin is phenolmelamine-urea-formaldehyde resin based.

The formaldehyde binder used has the following formulation:

parts by weight monoethylene glycol 300

urea 330

water 370

1000

The glue formulations used are as follows:

Check

grams grams Phenol-melamine-urea**formaldehyde resin 63% 5600 5600 hardener (15.5% ammonium chloride solution in water)

paraffin emulsion 50% 150 150 formaldehyde binder 560 total 6590 7150 gelling time in 73 79 seconds

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Check

Density (kg/m^) 705 695 flexural strength (N/mm^) 26.2 25.9 tensile strength (N/mm^) 0.27 0.26 tensile strength V100(N/mm2) 2.7 2.6 Thickness swelling in

2 hours (%) 7.1 6.2 thickness swelling

in 24 hours (%) 12.0 11.3 free formaldehyde

(mg/100 g of dry board) 12.8 7 formaldehyde reduction (7e) 45 The above results demonstrate that the formaldehyde binder according to the present invention can also be used for phenol-melamine-urea-formaldehyde resins, considerably reducing the emission of free formaldehyde without adversely affecting the properties of the boards.

Example 9

In this example, the formaldehyde binder used comprises an inorganic compound /^component (d)_/, illustrated in this case by sodium chloride.

The formaldehyde binder used has the following formulation.

H

Parts by weight monoethylene glycol 100% 270

urea 100% 318

sodium chloride 100% 50

water 362

total 1000

% solids 63.8

The glue formulations used in the various samples are as follows:

Check

grams grams Urea-formaldehyde resin (ratio

molar F:U=1.27:1) 3077 2770 hardener (ammonium chloride solution

15%) 400 450 paraffin emulsion 50% 250 250 ammonia 25? Baum? 5

formaldehyde binder 307 water 268

Total 4000 3770 Gel time in seconds 65 64 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The thickness of the boards is 17.3 mm.

The temperature of the press is 200?C and the pressure

? 35 kg/cm^. The dimensions of the pressed boards

they are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control _ 1 Density (kg/m^) 695 699 flexural strength (N/mm^) 19.9 19.5 tensile strength (N/mm^) 0.71 0.73 thickness swelling in 2 hours (7o) 7.0 6.6 thickness swelling in 24 hours (%) 20.5 20.8 free formaldehyde (mg/100 g of

dry table) 17 9.5 formaldehyde reduction (%) - 44 The results demonstrate that the sample containing the formaldehyde binder provides values that are equivalent to the control sample despite the fact that the formaldehyde binder replaces a part of the urea-formaldehyde resin in the formulation. The formaldehyde reduction is 44%.

1. Formaldehyde binder when for use in boards prepared from lignocellulosic materials using formaldehyde-based adhesives, which consists of a solution in water of:

a) at least one organic hydroxy compound with the exception of monovalent aliphatic C1_4 alcohols and

b) at least one amide.

2. The formaldehyde binder of claim 1, which; further contains, (c) an organic compound that acts as a solvent for (a) and (b) and also reacts with formaldehyde.

3. The formaldehyde binder of claim 2, wherein (c) is a monovalent aliphatic Cj_4 alcohol.

4. The formaldehyde binder of any of claims 1 to 3, which, further, contains (d) a water-soluble inorganic compound.

5.Formaldehyde binder of claim

4 where (d) is a water-soluble halide salt.

6. The formaldehyde binder of claim 5, wherein (d) is a water-soluble halide of an alkali metal or an alkaline earth metal.

7. The formaldehyde binder of claim 6, wherein (d) is sodium chloride, potassium chloride or calcium chloride.

8. The formaldehyde binder of any of claims 1 to 7, wherein component (a) is soluble in water or in a monovalent Cx_4-aliphatic alcohol.

9. The formaldehyde binder of claim 8, wherein component (a) is selected from divalent, trivalent and pentavalent alcohols containing up to 6 carbon atoms, monosaccharides containing up to 6 carbon atoms, disaccharides containing up to 12 carbon atoms and polysaccharides having an Ostwald viscosity of up to 200 mPas at 25°C and a concentration corresponding to a refraction of 37%.

10. The formaldehyde binder of claim 8, wherein component (a) is selected from aromatic alcohols and phenols.

11. The formaldehyde binder of claim 10, wherein component (a) is selected from monovalent and polyvalent aromatic alcohols containing a benzene ring and monovalent and polyvalent phenols.

12. Formaldehyde binder of any of claims 1 to 11 wherein component (b) is soluble in water or in a monovalent aliphatic alcohol.

13. The formaldehyde binder of claim 12, wherein component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

14. Formaldehyde binder of any of claims 1 to 13, characterised in that the weight ratio of component (a) to components (c) and (d), if present, to component (b) is 10:100 up to 400:100.

15. Formaldehyde binder of any of claims 1 to 4, characterised in that it contains from 20 to 80% by weight of the active ingredients.

16. Formaldehyde binder as claimed in claim 1, substantially as described hereinbefore in any of the examples.

17. A process for preparing the formaldehyde binder as claimed in claim 1, wherein

a) at least one organic hydroxy compound with the exception of monovalent aliphatic alcohols,

b) at least one amide and

c) possibly almerium an organic compound that acts as a solvent for (a) and (b) and also reacts with formaldehyde and

d) possibly a water-soluble inorganic compound and water are mixed at a temperature between room temperature and 70?C.

18. A process as claimed in claim 17, wherein (c) is a monovalent aliphatic C^_4 alcohol.

19. A process as claimed in claim 17 or 18 wherein (d) is a water-soluble halide salt.

20. The process as claimed in claim 19, wherein (d) is a water-soluble halide of an alkali metal or an alkaline earth metal.

21. Process as claimed in claim 20, wherein (d) is sodium chloride, potassium chloride or calcium chloride.

22. Process according to any of claims 17 to 21, wherein component (a) is soluble in water or in a monovalent aliphatic C^_4 alcohol.

23. Process according to claim 22, wherein component (a) is selected from divalent, trivalent and pentavalent alcohols containing up to 6 carbon atoms, monosaccharides containing up to 6 carbon atoms

?

of carbon, disaccharides containing up to 12

carbon atoms and polysaccharides having an Ostwald viscosity of up to 200 mPa s at 25°C

and a concentration corresponding to a refraction of 37%.

24. Process according to claim 22, wherein component (a) is selected from aromatic alcohols and phenols.

25. Process according to claim 24, wherein component (a) is selected from monovalent and polyvalent aromatic alcohols containing a benzene ring and monovalent and polyvalent phenols.

26. Process according to any of claims 17 to 25, wherein component (b) is soluble in water or in monohydric aliphatic alcohols.

27. Process according to claim 26,in

where component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

28. Process according to any of claims 17 to 27, characterised in that the weight ratio of component (a) to component (b) is

(c) and (d), if present, to component (b) ? 10:100 up to 400:100.

29. Process according to any of claims 17 to 28, characterised in that the formaldehyde binder contains 20 to 80% by weight of the active ingredients.

30. A process for preparing boards from lignocellulosic materials using a formaldehyde-based adhesive wherein a formaldehyde binder according to any of claims 1 to 16 is added to the adhesive.

31. A method as claimed in claim 30, substantially as previously described in the examples.

32. Boards when produced by a process as claimed in claim 30 or claim 31.

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PATENT OFFICE

25 SOUTHAMPTON BUILDINGS

L O N D R

I, the undersigned, being an officer duly authorized under Section 62(3) of the Patent and Design Laws 190?, to sign and issue certificates on behalf of the Comptroller General, hereby certify that the annex is a true copy of the documents as originally filed in accordance with the patent application herein identified.

-Under the Model Regulations 1962 (Re-Registrations of Companies), if a company named in this certificate (and documents annexed thereto, if included) has re-registered under the Companies Act 1980 under the same name as that under which it was registered immediately before the re-registration - except by substitution, or inclusion, as the last part of the name, of the words "public company limited by guarantee" or their Welsh equivalent, references to the name of the company in this certificate shall be treated as references to the name under which it was so re-registered.

According to the regulations, the words "Public Company with Limited Liability" can be replaced by pll-c?7 pie., P.L.C. or FLC.

Reregistration under the Companies Act does not constitute a new legal entity but simply subjects the company to certain additional provisions of the Companies Act. IN WITNESS WHEREOF 27 JANUARY 1984 LECCI: SUI DR?VETTI , 1 u?7

Patent Form No. 1/77

(Redolo 8, 16, 1?) July 26, 1983

The real -Cica tor? ; Test Office

$2 Southampton. Dui Ldingo 1783

1 London WG 2 A LAI 20128

HI CLi X DITA 1JL'U THE RELEASE OF A UH V.V ETTO

The relaunch of a brave one is requested dui ,-iotco

aoricto in bado ullu prosante question

I UirorLuiunco from the x-ictiicdnriL? or

d oli ' ug?nttj (inaorira uu ili sponi bx 1 :: ) 42.142-637

II Title from the invanii oriti BINDER FORMALDE I D I CO

III Closer. (i ) (vodajii nou i )

w, , , , , ENIGMA N.V,

Nouo (first or wrong Ri e. h , ^d e ut n j

, County: Netherlands Antilles

Inrt i r i z zo :

Jiaiideis.ka.deu_ 8 Jluracao ,-~An ti 1- 1 e- Dutch?

Nationality?

Noui (of the no coin Rie lii co ?.nt - , :.i; pib di uno)

I u ? i r i z :?. o

Ru zi Dilu? i l?

IV Sent^? (vetlnni l'.uti. ;.)

( u ; u n.i . i 11 c nu u : . ?. or not <_? ' u * > i , i. II 1 i'oi'miiliirio purb :i v- : t: v p.? V

V ?i; i o r i '.v.J .?..ion e ..i ..penis.. vi.: ..c ? ;? ?!'

FRANK B.DHN & CO.

?e>C Yes??

1?+%?'

vi Service address (see note bXr-nu IT7

15-19 Kingsway London *C2B 6UZ

Imperial House

vi 1 Priority Statement (see note 6)

Country ? Filing date Filing number 8303350

February 7, 1983?

UK

Vili The application claims an earlier date based on

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(see note 7)

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s ai.o <3=F=

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XI rirn odasi note Q)

FRANK B. DHN & CO.

NOTI?? .

1. This form, when completed, should be brought or sent to the U.N. llrov-o l. I:i ind i ?.?::??: with ?. ta.is.ii proMcrittn or . two copies of the m neri zi DUI: of the invention.

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oc l? vi c. hi or iie ut: e de: a

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SIB.84684

Cago 4&

DESCRIPTION of the industrial invention entitled: "FORMALDEHYDE BINDER" and the procedure for preparing it and obtaining wood panels from it.

of the firm -of-the-Dutch-Ants? IENICMA NtV-.

eon code in?CURA^AO 4Antillo Olandesir)?

SUMMARY-

A formaldehyde binder is described for bonding lignocellulosic sheet materials such as particle board, plywood, and plywood, in which a formaldehyde-based adhesive is employed.

The le?ant&--criSm comprises an organic hydroxy compound and

DESCRIPTION

Boards such as particleboard, grayboard, and the like are made from lignocellulosic materials using adhesives. The preferred adhesives (or glues) are formaldehyde-based, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde, and resorcinol-formaldehyde resins, or mixtures thereof. It is well known that boards made using these adhesives have a formaldehyde odor that is both harmful and unpleasant. Formaldehyde is released both during the production of these boards and during their storage and final use.

Many methods have been proposed to prevent formaldehyde emissions, but all are ineffective, reduce the properties of the boards, or require complicated application processes. Some of these processes involve spraying or extensively coating the hot boards emerging from the press with various solutions, such as urea solutions and/or ammonia or ammonium salts. In general, these methods are undesirable for industrial applications because they require additional processing steps and are inefficient.

Other methods involve the use of very complicated mixtures of a large number of components, some of which are natural glues. These products are also not very efficient. One obstacle is the fact that the properties of natural products are not consistent.

Another way to reduce free formaldehyde content involves using an aqueous suspension of urea agglomerates coated with a special wax. This method also requires a separate feed line because the product is not added to the adhesive formulation itself.

It is an object of the present invention to provide a formaldehyde binder that effectively reduces formaldehyde odor without reducing the properties of the board, without changing the reactivity of the adhesive formulations, and without requiring any additional steps in the production of particleboard, plywood, or blockboard.

The present invention provides a formaldehyde binder for use in boards prepared from lignocellulosic materials using formaldehyde-based adhesives which consists of a solution in aqueous solution of a) at least one organic hydroxy compound with the exception of monovalent aliphatic C 1 -4 alcohols and

b) at least one amide.

>n od- H 3 rruM/gitO o<i* & ?.

14?formaldehyde binder.co may also contain (c) an organic compound which acts as a solvent for (a) and (b) and also reacts with formaldehyde, -e-,?or? (4^) -an inorganic compound which is soluble in water. -The organic compound (c) is preferably a monovalent aliphatic Cj_4 alcohol. The inorganic compound? (4-)???preferably a Baie?a-l-og-enw o. Although the individual components are not soluble in water, they can dissolve in water if a mixture of them is heated in water up to 70?C.

Preferably, the organic hydroxy compounds /_component (a)J7 are soluble in water or in 4

lower monovalent aliphatic alcohols. Examples of such preferred hydroxy compounds are the divalent, trivalent and pentavalent alcohols containing up to

6 carbon atoms, monosaccharides containing up to 6 carbon atoms, disaccharides containing up to 12 carbon atoms, and polysaccharides having an Ostwald viscosity of up to 200 mPa s at 25°C and a concentration corresponding to a refraction of 37%. Other examples of preferred hydroxy compounds

These are aromatic alcohols and phenols that are preferably used alone or in combination with one or more of the above-mentioned dihydric, trihydric, or pentahydric alcohols, or monosaccharides, disaccharides, or polysaccharides. Phenols and aromatic alcohols can be monohydric or polyhydric phenols and monohydric or polyhydric aromatic alcohols containing a benzene ring.

Specific examples of suitable organic hydroxy compounds are monoethylene glycol, diethylene glycol, glycerin, pentaerythritol, fructose, mannose, sorbitol, dextrose, sucrose, maltose, lactose, dextrin, phenol, resorcinol, hydroquinone and the like.

Preferably, the amides /_ component (b)_/ used in the formaldehyde binder of the present invention are equally soluble in water or in lower monovalent aliphatic alcohols. Particularly preferred are aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

Suitable examples of amides are urea, thiourea, formamide, acetamide, benzamide, oxamide, succinamide, malonamide and the like.

If desired, to enhance solubility, the formaldehyde binder of the present invention may additionally contain additives /_ component (c)__7 which are lower monovalent aliphatic alcohols such as methanol, ethanol, isopropanol and the like.

A cheaper, formal??!binder; more efficient is obtained if inorganic compounds /_component?-('d)_/ are added which are preferably halide salts, still preferably halides of sodium chloride, potassium chloride.

To the ????

The ratio of organic hydroxy compound ^component (a) to component (c), if present^/ and inorganic compound, -/^component (d)-!? if presentC-e_ -J- to amide ^component (t)_/ is preferably 10:100 to 400:100, particularly 10:100 to 200:100 by weight. The formaldehyde binder of the present invention may be added to conventional glue formulations in amounts ranging from 1 to 10%, preferably 3 to 7%, formaldehyde binder solids, based on the weight of the liquid resin containing 65% by weight resin solids.

The formaldehyde binder of the present invention may contain from 20 to 80% by weight, preferably from 50 to 70% by weight, of the active ingredients /^components (a) and (b)

?(d)t? if presonei_7? The water content of the formaldehyde binder depends on the solubility of the active ingredients and the amount of water that can be tolerated in the glue formulations.

The formaldehyde binder of the present invention can be produced simply by adding the active ingredients and water to a mixer and stirring until the active ingredients have dissolved. This can be done at room temperature or at elevated temperatures up to 70°C.

The formaldehyde binder of the present invention can be used whenever boards are prepared from cellulosic materials using formaldehyde-based adhesives, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde or resorcinol-formaldehyde resins or mixtures thereof.

When to use formaldehyde binder

of the present invention, it is possible to produce boards containing in reality less than 10 mg of free formaldehyde per 100 g of the dry board, as determined by the F.E.S.Y.P. (Fed?ration Europ?enne des Syndicats des Fabricants de Panneaux de Particules) perforator method No. EN 120.

The extent of free formaldehyde reduction depends on many factors and can therefore vary widely. If the free formaldehyde emission

If the free formaldehyde emission is high (greater than 50 mg of formaldehyde per 100 g of dry table), the reduction can be as high as 60 to 85%. If the free formaldehyde emission is relatively low, i.e. 20 to 50 mg of free formaldehyde per 100 g of dry table, the maximum reduction is usually 50 to 60%. The amount of reduction achieved also depends on the amount of formaldehyde binder used: the more formaldehyde binder is used, the lower the amount of free formaldehyde.

When the active ingredients of the formaldehyde binder are used in combination with each other, the reduction of free formaldehyde is surprisingly much higher than the sum of the effects of the separate components and they have no adverse effect on the reactivity of the glue formulation or the properties of the boards.

The following examples illustrate the present invention. Parts and percentages are by weight.

Example 1

In this example, the organic compound containing hydroxyl groups is glycerol and the amide is urea.

The synergistic behavior is illustrated here

of these two compounds. Various glue formulations are prepared and each is subsequently used to produce particleboard.

The control does not contain any of the components of the formaldehyde binder according to the present invention. Sample 1 contains both glycerin and urea, Sample 2 contains only glycerin, and Sample 3 contains only urea.

It should be noted from the tables below that glycerin, when used alone (Sample 2), is a very effective formaldehyde binder but urea (Sample 3) gives poorer formaldehyde reduction and lower mechanical and water resistance values, however, when urea is used in combination with glycerin (Sample 1), it gives values that are equivalent to those of glycerin alone.

It is therefore possible to use a cheaper and less effective product (urea) and make it react as effectively as a more expensive and more effective product (glycerin). Effectiveness refers to the ability to absorb formaldehyde and maintain good mechanical properties and water resistance without changing the reactivity of the glue formulation and without the need for any special equipment for its use. The formaldehyde reduction in this case is actually 467P.

The formulations of the various samples used are as follows:

X:parts s parts 3^;parts by weight by weight by weight glycerin (100%) 270 590

Urea (100%) 320 590 water 410 410 410

1000 1000 1000 % solids 59 59 59 The glue formulations used are as follows:

Control ^ 2 3 grams grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1.27:1) 3077 3077 3077 3077 Hardener (ammonium

chloride 157?) 400 400 400 400 paraffin emulsion 50% 250 250 250 250 Ammonium 25?Bauin? 5 5 5 5 sample 1 308

sample 2 308 sample 3 308 water 268

total 4000 4040 4040 4040 gelling time in seconds 68 68 71 62

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Controls) 1_ \_ 3_ Density (kg/cm^) 683 669 663 657 Flexural strength 19.9 18 ?1 17.3 16.3 Tensile strength 0.73 0.72 0.71 0.63 (N/mm^)

Swelling of

thickness in 2 hours (?) 5.2 4.9 4.5 5.4 Swelling of (?) 51.4 49.9 47.4 53.1 thickness in 24 hours

15.8 8.5 8.7 11.7 free formaldehyde

(mg/100 g of dry table)

Example 2

This is another example illustrating the synergistic behavior of glycerin and urea in reducing free formaldehyde in particleboard while maintaining the mechanical properties of the boards and also their water resistance.

The control does not contain any of the components of the formaldehyde binder according to the present invention. Sample 1 contains both components of the formaldehyde binder according to the present invention, and Sample 2 contains only one of the two components (the more effective of the two components).

It is to be noted here again that only sample 1 gives free formaldehyde which is below

10 mg/100 g of dry tablet (which is the desired level for class El) and is the only one with absolutely equivalent mechanical properties and water resistance. The formaldehyde reduction is actually 34%.

The formulations of the various samples used are as follows:

__parts by weight parts by weight glycerin (100%) 128 128 urea (1007.) 424

water 448 872

1000 1000

% solids 55.2 12.8 The glue formulations used are as follows:

I'm checking the 2

grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1.27:1) 3077 3077 3077 Hardener (ammonium

chloride 15%) 400 400 400 paraffin emulsion 50% 250 250 250 Ammonium 25?Baum? 5 5 5 sample 1 268

sample 2 268

water 268

total 4000 4000 4000

gelling time in seconds 66 67 69

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm2. The produced boards measure 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 Density (kg/cm^) 685 684 687 Flexural strength (N/mm2) 20.7 20.6 19.4 Tensile strength (N/mm^) 0.74 0.73 0.67 Thickness swelling

in 2 hours (%) 11.0 7.9 8.6 Absorption in 24 hours (%) 23.5 23.2 23.7 free formaldehyde 14.3 9.5 12.3 (mg/100 g of dry tablet)

Example 3

This example illustrates the effectiveness of monoethylene glycol together with urea as a formaldehyde binder.

Two formulations are prepared: the control without any of the formaldehyde binder ingredients of the present invention and Sample 1 which contains both monoethylene glycol and urea.

Boards are produced from these two glue formulations and it has also been demonstrated here that with the formaldehyde binder according to the presbyopic inven-. o/JCr?

tion are obtained with a urea-formaldehyde resin which normally provides tables classified as E2 (control), tables classified as E 1 (sample 1).

The reduction of formaldehyde in this case is 37%.

The formulation of sample 1 used is as follows:

Sample 1 parts by weight monoethylene glycol 100% 360

urea 100% 365 water 275

1000

% solids 72.5

The glue formulations used are as follows:

Check

_ grams grams urea-formaldehyde resin 65% 3077 3077 (molar ratio F:U = 1.27:1)

hardener 400 400 (ammonium chloride 15%)

50% paraffin emulsion 250 250 ammonia 25?Baum? 5 5 sample 1 - 268 water 268

total 4000 4000 gel time in seconds 66 60 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. Boards are pressed for 10.9 and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm2. The dimensions of the produced boards are 40 x 56 mm.

The results obtained are reported in the following table and are average values.

Control l Density (kg/cm^) 685 684 Flexural strength (N/mm^) 20.7 20.2 Tensile strength (N/mm^) 0.74 0.74 Thickness swelling

in 2 hours (7?) 110 8.6 Absorption in 24 hours (7,) 23.5 22.6 free formaldehyde 14.3 9.0 (mg/100 g of dry table)

Example 4

This example illustrates the synergistic behavior of monoethylene glycol and urea.

Tables are prepared from three different formulations: the control in which none of the ingredients of the formaldehyde binder of the present invention are used, sample 1 in which both ingredients of the formaldehyde binder of the present invention are used, and sample 2 in which only one ingredient is used.

It is obvious from the results obtained and reported below that sample 1 containing both ingredients is much more effective than sample 2 containing only one ingredient (the more effective of the two ingredients).

The formaldehyde reduction obtained in this case is 32%.

The formulations of the various samples used are as follows:

1 2 parts by weight parts by weight monoethylene glycol 100% 230 580 urea 100%. 350

water 420 420

1000 1000 % solids 58 58 The glue formulations used are as follows: Control ^ 2 .

grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1,27:1) 3077 3077 3077

Hardener (ammonium

chloride 15%) 400 400 400

paraffin emulsion 50% 250 250 250

Ammonium 25?Baum? 5 5 5

sample 1 268

sample 2 268

water 268

total 4000 4000 4000

time of gelifi- 70 71 76

cation in seconds

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 mm.

The results obtained are reported in the following table. They are average values.

Control_ 1_ 2 Density (kg/m^) 688 688 687 Flexural strength (N/mm^) 17.6 17.6 17.5 Tensile strength (N/mm^) 0.55 0.60 0.56 Thickness swelling

in 2 hours (%) 6.7 4.9 4.7 Absorption in 24 hours (??) 20.1 20.1 19.5 free formaldehyde 15.0 10.3 12.3 (mg/100 g of dry table)

Example 5

This example illustrates the use of a resin with a different molar ratio as well as various addition levels of the formaldehyde binder itself.

The formaldehyde binder used has the following formulation:

i in

100% glycerin 270

urea 1007? 318 water 412

1000

% solids 58.8 ?

The glue formulations used in the various

samples are as follows:

Control 1 2 3 grams grams grams grams Urea-formaldehyde resin 65% 3077 3077 3077 3077 (molar ratio F:U=1.4:1)

Hardener (ammonium chloride 293 380 380 380

15% )

50% paraffin emulsion 250 250 250 250 ammonia 25?Baum? 5 5 5 5 formaldehyde binder 154 215 375 water 375 134 73 total 4000 4000 4000 4087 gel time in sec. 73 73 72 75 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200?C and the pressure is 35 kg/cm^. The dimensions of the boards produced are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1

Density? (kg/m^) 680 687 ' 685 688

flexural strength 22.0 22.5 22.3 21.6 (?/????^)

tensile strength 0.61 0.63 0.66 0.64 (N/mm^)

swelling of thickness in

2 hours (%) 10.1 9.3 8.8 9.5 thickness swelling

in 24 hours (%) 20.6 21.8 21.0 21.5 free formaldehyde 22.2 13.0 10.1 9.5 (mg/100 of dry tablet)

It is worth noting that the mechanical properties and water resistance of the boards are equivalent and

the reduction of formaldehyde is 41% in the case of sample 1, 55% in the case of sample 2 and 57% in the case of sample 3.

Example 6

This example illustrates different types of polyols, two different types of amides, an additive, and a variation in the ratio of alcohol to covering amide ranging from 57.5/100 to 385/100.

The various types of formaldehyde binder used are as follows:

1 2 3 4 , * dextrose 230

diethylene glycol 330

monoethylene glycol 260 110 glycerin 500

sucrose 110 sorbitol 140

methanol 200 140 80 ho ho urea 400 300 130 350 330 thiourea 170

water 370 370 370 370 370 370 Total 1000 1000 1000 1000 1000 1000 70 solids 63 63 63 63 63 63

Weight ratio of

57.5/100 110/100 270/100 385/100 80/100 91/100 alcohol/amide

All above values are parts by weight.

The glue formulations used in the various samples are as follows:

1 2 3 4 5 6

Control1 grams grams grains: grams- grams grams * Urea-formaldehyde resin grams

65% (molar ratio F:U= 3077 3077 3077 3077 3077 3077 3077 1.27:1)

Hardener (ammonium chloride, 15% solution) 400 500 500 500 500 500 500

paraffin emulsion 507? 250 250 250 250 250 250 250

I IO

Ammonia 25? Baum? 5 4S

formaldehyde binder

sample 1 307

sample 2 307

sample 3 307

sample A 307

sample 5 307

sample 6 307

water 268

4134 4134 4134 4134 total 4000 4134 4134

65 66 65 67 66 62 69 gelling time in sec.

Single layer boards are prepared

in the laboratory by spraying each of these formulations on 25 kg of wood chips.

The boards are pressed for 10, 9, and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the boards produced are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 3 4 5 6 Density (kg/m3) 688 689 687 685 690 685 692 flexural strength (N/mm^) 19/6 19^5 18.3 19.5 20 .1 19.3 19.4 tensile strength (N/mm^) 0.71 0.69 0167 0.73 0.74 0.72 0.70 thickness swelling in 7.0 6.5 5 .0 5.5 6.1 6.5 6.2 2 .hours% . 19.7 19.3 20.0 19.8 19.5 20.1 19.9 thickness swelling in ' ? ho 24 hours (%) ?>

(mg/100 g of , _ _ ? formaldehyde free dry table.). 16 8'9 8.6 11.0 9.0 9.8 8.5 formaldehyde reduction % - 45 47 32 44 39 47

The above results demonstrate that

all samples used have equivalent values

to the control and that the reduction of formaldehyde is of the order of 32 to 47%.

Example 7

In this example, three different types of organic compounds containing hydroxyl groups are exemplified by dextrin, phenol, and resorcinol. A monohydric alcohol that functions as an additive other than methanol, namely ethyl alcohol, is also illustrated.

The various types of formaldehyde binder used

they are as follows:

monoethylene glycol 230

dextrin 140

phenol 130 resorcinol 130 methanol 140 130 130 ethanol 80

urea 35? 350 370 370 water 340 370 370 370

1000 1000 1000 1000 % solids 66 63 63 63 All values above are parts by weight. Formaldehyde binder samples are used in this example to replace a portion of the resin used.

What glue formulations are actually used?

they are as follows:

Control ^ ^ 3 ~ 4 grams, grams grams grams grams Urea-formaldehyde resin ?

3077 2770 2770 2770

65% (molar ratio F:U= 2770 1.27:1)

Hardener (ammonium chloride, 15% solution) 4p0 500 400 450 400 paraffin emulsion 50% 250 250 250 250 250 Ammonia 25? Baum? 5

formaldehyde binder

sample 1 307 - sample 2 307

sample 3 307 sample 4 307

water 268

total .40.00 3827 3727 3777 3727 gelling time

in sec. 65 64 62 63 63 ?*

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed at 10.9 and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The pressed boards measure 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 3 4 Density (kg/m^) 702 698 695 705 710 flexural strength (N/mm2) 20 ,1 !9r5 19,7 20,0 20,8 tensile strength (N/mm2) 0,75 0,70 0,75 0f73 0,72 thickness swelling in j 7,1 6,8 .6,5 6,3 6,6 2 hours (70 _ t

thickness swelling in 20.3 21.5 21.3 21.8 21.3 24 hours (%)

free formaldehyde 13.1 9.6 9.2 8.2 10 formaldehyde reduction % 30 37 24 The above results demonstrate

that all samples have values that are equivalent to the control sample containing no formaldehyde binder even though the latter replaces an equivalent amount of urea-formaldehyde resin in the formulation. The formaldehyde reduction in this example varies from 24 to 37%.

Example 8

In this example, a type of formaldehyde binder is used and the resin is based on phenolmelamine-urea-formaldehyde resin.

The formaldehyde binder used has the following formulation:

parts by weight_ monoethylene glycol 300

urea 330

water 370_

1000

The glue formulations used are as follows:

?

'!*-*

Control I grams_ _ grams Phenol-melamine-urea*-formaldehyde resin 63% 5600 5600 hardener (15.5% ammonium chloride solution in water)

50% paraffin emulsion 150 150 formaldehyde binder - 560 total 6590 7150 gelling time in 73 79 seconds

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10.9 and 8 seconds/min. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm². The dimensions of the produced boards are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Check

Density (kg/m^) 705 695 flexural strength (N/mm^) 26.2 25.9 tensile strength (N/mm^) 0.27 0.26 tensile strength V100(N/mm2) 2.7 2.6 Thickness swelling in

2 hours (%) 7.1 6.2 thickness swelling

in 24 hours (%) 12.0 11.3 free formaldehyde

(mg/100 g of dry board) 12.8 7 formaldehyde reduction (%) ~ 45 The above results demonstrate that the formaldehyde binder according to the present invention can also be used for phenol-melamine-urea-formaldehyde resins, considerably reducing the emission of free formaldehyde without adversely affecting the properties of the boards.

? Koompio 9-? In this example,? i4? ligand? fermaidei-dicc usetj comprises an inorganic compound (d)_/, illustrated in this case by sodium a?tifide.

The used formaldehyde alloy has the following form:

??7i???

1. Formaldehyde binder when for use in boards prepared from lignocellulosic materials using formaldehyde-based adhesives, which consists of an in-water solution of:

a) at least one organic hydroxy compound with the exception of monovalent aliphatic C1_4 alcohols and

b) at least one amide,

/? t*f> *uQ. efltourt. jo vn fn tjusg/sb C

2-r-Formaldehyde binder of claim 1 which. further contains?, (c) an organic compound which acts as a solvent for (a) and (b) and also reacts with formaldehyde.

?? The formaldehyde binder of claim 1, wherein (c) is a monovalent aliphatic Cj_4 alcohol.

-A-,? Formaldehyde binder-of-any-of-claims 1 to 3, which, in addition, contains (d) mr water-soluble inorganic compound. y'

5.Formaldehyde binder of the riy?indication

4 where (d) is a water-soluble halide salt.

6. The formaldehyde binder of claim 5, wherein (d) is a water-soluble halide of an alkali metal or an alkaline earth metal.

7. The formaldehyde binder of claim 6, wherein (d) is sodium chloride, potassium chloride. The formaldehyde binder of any of claims 4 is 1 or %, wherein component (a) is soluble in water or in a monovalent C 1 -4-aliphatic alcohol.

The formaldehyde binder of claim 5, wherein component (a) is selected from divalent, trivalent and pentavalent alcohols containing up to 6 carbon atoms, monosaccharides containing up to 6 carbon atoms, disaccharides containing up to 12 carbon atoms and polysaccharides having an Ostwald viscosity of up to 200 mPa s at 25°C and a corresponding refraction of 37%.

?fK). Formaldehyde binder of claim wherein component (a) is selected from aromatic alcohols and phenols.

6 KL. Formaldehyde binder of claim f

?? i where component (a) is selected from monovalent and polyvalent aromatic alcohols containing a benzene ring and monovalent and polyvalent phenols.

7 M . Formaldehyde binder of any of claims 1 to 6 wherein component (b) is soluble in water or in a monohydric aliphatic alcohol.

' 9

8 IB. The formaldehyde binder of claim 3, wherein component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

9 ]? . Formaldehyde binder of any of claims 1 to 8, characterised by what is.

the weight ratio of component (a) plus components (c) and? (44, if present, to component (b) is 10:100 up to 400:100.

1? . Formaldehyde binder of any of claims 1 to characterized in that it contains from 20 to 80?> by weight of the active ingredients.

1-?. Formaldehyde binder as claimed in claim 1, substantially as described hereinbefore in any of the examples.

1?. Process for preparing the formaldehyde binder as claimed in claim 1, wherein

a) at least one organic hydroxy compound with the exception of monovalent aliphatic C1_4 alcohols,

b) at least one amide and

c) possibly at least one organic compound that acts as a solvent for (a) and (b) and also reacts with formaldehyde g

d-)? possibly an inorganic or water-soluble compound and water are mixed at a temperature between room temperature and 70?C.

/3 . Process as claimed in claim 1Z, wherein (c) is a monovalent aliphatic Cj_4 alcohol.

?r9~. ? Process as claimed in claim 17 or 18 wherein (d) is a water-soluble halide salt.

20. Process as claimed in claim 19, wherein (d) is a water-soluble alkaline earth metal or alkaline earth metal halide.

21. A preparation as claimed in claim 20, wherein (d) is sodium chloride, potassium chloride or calcium chloride.?

/48? ? Procedure according to any of the fZ claims

cation ?1-7?a?24, where component (a) is soluble in water or in a monovalent aliphatic C1_4 alcohol.

2@ . Process according to claim ^ ^4. wherein component (a) is selected from divalent, trivalent and pentavalent alcohols containing up to 6 carbon atoms, monosaccharides containing up to 6 carbon atoms

NV

r

of carbon, disaccharides containing up to 12

carbon atoms and polysaccharides having an Ostwald viscosity of up to 200 mPa s at 25°C

and ww?eonocntroaiono corriopondcMrtro?at a refraction of 377o.

46 ???.Process according to claim 2S./4 wherein component (a) is selected from aromatic alcohols and phenols.

/?? .Method according to claim

where component (a) is selected from monovalent and polyvalent aromatic alcohols containing a benzene ring and monovalent and polyvalent phenols.

6. Process according to any of the claims

/?

indications from to ?5-, where component (b) is soluble in water or in monovalent aliphatic alcohols.

K

/0 ^ . Process according to claim ? ,in

where component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing a benzene ring.

20 W& . Process according to any of the claims

19

indications 1% up to characterized by what is the weight ratio of component (a) plus components.

(c) and?(d-)-, if present, to component (b) ? 10:100 up to 400:100.

%

ZJ . Process according to any of claims 1 to 20, characterised in that the formaldehyde binder contains 20 to 80% by weight of the active ingredients.

22 ??. A process for preparing boards from lignocellulosic materials using a formaldehyde-based adhesive wherein a formaldehyde binder according to any of claims 1 to 1^ is added to the adhesive.

Z$ 3? . Process as claimed in the resale

cation ??, substantially as previously described in the examples.

Z4 ? . Boards when produced by a process as claimed in claim SB or claim 3 %.23,

p.p.ENIGMA N.V.

%

?li ?~/?

Z a#Q/?/e ??/''n c? Z/ es(ah & o

SUMMARY

A formaldehyde binder is described for use in non-cellulosic sheet materials such as particle board, plywood, or plywood, in which a formaldehyde-based adhesive is employed.

The binder comprises an organic hydroxy compound and an amide.

(for compliant translation)

Qllberto Tonon

, ,.^a Short?* S p A I

\SacWh W^ TJ?

V ?! ?

a

1 -A \A? V 43 Oi3t*? JJTI i

Formaldehyde binder

It is known that boards made from cellulose-based materials in which the adhesive used is formaldehyde-based, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde, resorcinol-formaldehyde, or mixtures thereof, emit a formaldehyde odor that is both harmful and unpleasant.

This problem is acute both during the production of the boards themselves and after their final use.

There have been many ways to 'avoid formaldehyde odor emission,' all of which are ineffective, reduce the properties of the boards, or require complicated application methods.

Some of these methods are to spray or coat the hot plates as they come out of the press with various solutions such as urea solutions, and, or ammonia, or ammonium salts.

These types of methods are generally not liked by industries as they require extra operations in their production and are, in any case, not very effective.

Other methods include the use of very complicated products that are mixtures of a large number of *

*

products some of which are natural glues.

These products are not very effective, a disadvantage being the fact that natural products are not consistent.

Another way to reduce free formaldehyde is to use urea, which is coated in a special wax. This method also requires a separate feed line, as the product is not added to the glue formulation itself.

The purpose of the present invention is to provide a formaldehyde binder that effectively reduces formaldehyde odor without reducing the properties of the board, without changing the reactivity of the glue formulations, and also without requiring any extra operations in the production of particleboard, plywood, or blockboard.

The formaldehyde binder according to our present invention can be used whenever boards are prepared from sinocellulosic materials in which the adhesives are formaldehyde-based, such as ureaformaldehyde, melamine-formaldehyde, phenol-formaldehyde, resorcinol-formaldehyde or mixtures thereof.

The product according to our present invention is not the single product as such but the mixture of two or more separate products not so effective when used separately, but extremely effective when combined together and used as a new product.

With the product according to our invention, we can produce boards effectively containing less than 10 mg of formaldehyde per 100 g of board using the FESYP method.

The percentage amount of free formaldehyde reduced depends on many factors, so the range is very wide.

If the free formaldehyde emitted is at high levels (above 50 mg of formaldehyde per 100 g of table) then the reduction is greater in percentage and can reach up to 60-857o.

However, if the values for free formaldehyde are

already at the lowest levels, i.e. 20-50 mg per 100

g of table then the reduction normally reaches a maximum of 50-60%. The values achieved also depend on the quantity of formaldehyde binder used.

The more formaldehyde binder is used, the less free formaldehyde is obtained.

The product according to our invention consists of one or more organic compounds containing one or more

1

hydroxyl groups and one or more amides.

Various suitable organic compounds containing hydroxyl groups are methanol, ethylene glycol, glycerin, dextrose, phenol, and resorcinol.

Suitable amides are urea, thiourea, formamide, acetamide, benzamide, oxamide, succinamide, malonamide.

The most suitable of the above-mentioned products are: glycerin and, or ethylene glycol and urea.

The ratio of organic compound(s) containing one or more hydroxyl groups to amides used is 10-200/100 parts by weight. Such a combination of chemicals may be added to glue formulations in amounts ranging from 1-10% in liquid resin, the resin being taken as 657% and the product according to our invention being taken as 100% solid.

*

Formaldehyde binder is actually prepared as a solution in water. The amount of water added depends entirely on the solubility of the product and the amount of water tolerated in the glue formulations. Solutions range from 20-80% concentration.

?.

The method of producing formaldehyde binder according to our invention is very simple and

that is, by adding them to a mixer and stirring until the products are dissolved at room temperature or by increasing the temperature up to 70°C.

The surprising effect of the formaldehyde binder according to the present invention is the fact that when the individual components are used as such there is no formaldehyde reduction effect or only a partial one and not without influencing the properties of the boards.

When one or more hydroxyl-containing organic compounds are used in combination with one or more amides, the reduction of free formaldehyde is surprisingly much greater than the sum of the effects of the separate components and there is no detrimental effect on the reactivity of the glue formulation or the properties of the boards.

The following examples will illustrate our invention and are not intended to be taken as a limitation of our invention.

W

on the properties of the tables.

Illustranii-Jre^pfesente invention the examples

V,

W

Example 1

In this example, the organic compound containing hydroxyl groups is glycerin and the amide is urea.

/iy/ftUo J / Here the synergistic behavior of these two compounds is illustrated. Various glue formulations are prepared and each is subsequently used to produce particleboard.

Does the control contain none of the gomponen-fe4?

nc/yfio-4e4?formaldehyde binder according to the invention. Sample 1 contains both glycerin and urea, Sample 2 contains only glycerin, and Sample 3 contains only urea.

It should be noted from the tables below that glycerin, when used alone (Sample 2), is a very effective formaldehyde binder but urea (Sample 3) gives poorer formaldehyde reduction and lower mechanical and water resistance values, however, when urea is used in combination with glycerin (Sample 1), it gives values that are equivalent to those of glycerin alone.

Pcyh'o/ec

It is therefore possible to use a cheaper and less effective product (urea) and make it react as effectively as a more expensive and more effective product (glycerin). Effectiveness refers to the ability to absorb formaldehyde and maintain good mechanical properties and water resistance without changing the reactivity of the glue formulation and without the need for any special equipment for its use. The formaldehyde reduction in this case is actually 46%.

tJt ceifa- tf?aJx,

The formulations*'of the various samples used are

as follows:

parts 2 parts ? ;p?iM:i? in?fiero ir. weight ? iti?pee-glycerin (1004) 270

Urea (1007.) 320 590 water 10 410 410

1000 1000 1000 . solids 5-9 54 54 t

glue formulations used in breast and heme:

Control ^ 2 3 grams grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1.27:1) 3077 3077 3077 3077 Hardener (ammonium

chloride 15%) 400 400 400 400 paraffin emulsion 50% 250 250 250 250 Ammonium 25?Baum? 5 5 5 5 sample? \3/ioinn&. *00%,

sample?2- w*a. /o0% 2<S ! 91 sample 3- - - 3??water 268 *27 JQ>7 *27 total 4000 4040 4040 4040 gelation time in seconds 68 68 71 62

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The board thickness is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm^. The dimensions of the produced boards are 40 x 56 cm.

??? -

The results obtained are reported in the following table and are average values.

Counterlift 1

Density (kg/cm^) 683 669 663 657 Flexural strength 19.9 18.1 17.3 16.3 (N/mm^)

Tensile strength 0.73 0.72 0.71 0.63 (N/mm^

Swelling of

thickness in 2 hours (?) 5.2 4.9 4.5 5.4 Swelling of {% ) 51.4 49.9 47.4 53.1 1 thickness in 24 hours

15.8 8.5 8.7 11.7 free formaldehyde

(mg/100 g of dry table)

Example 2

This is another example illustrating the synergistic behavior of glycerin and urea in reducing free formaldehyde in particleboard while maintaining the mechanical properties of the boards and also their water resistance.

fp <3 far-r&h

Does the control not contain any of the components?

flvj/tro.

of the formaldehyde binder according to the present invention. Sample 1 contains both components of the formaldehyde binder according to the present invention and Sample 2 contains only one of the two components.

until rt&?>*n'fc

(the most effective of the two components.) .

It is to be noted here again that only sample 1 gives free formaldehyde which is below

10 mg/100 g of dry tablet is the desired level for the Eli class and is the only one to have absolutely equivalent mechanical properties and water resistance. The formaldehyde reduction is actually 34%.

I c/t tp/fa, j

The formulations of the various uoafei samples are as follows:

-2--pa-r-ti in pe&o- pa-c-t-i -in -pe-sp-? glycerine (100%) 128

urea (100%) 424

water 872

1000 1000

% solids 55.2 12.8 formulaai-oai of glue used-are-they?soma-follow-?

?

Control ^ 2

grams grams grams

urea-formaldehyde resin 657o (ratio

molar F:U 1.27:1) 3077 3077 3077 Hardener (ammonium

chloride 15%) 400 400 400 paraffin emulsion 50% 250 250 250 Ammonium 25?Baum? 5 5 5 sample ? 1-^// & PMQ. too?/i ?M sample? 2? vroo- fOD/C. - //4

water 268 23* total 4000. 4000 4000

gelling time in seconds 66 67 69

Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. The boards are pressed for 10, 9, and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200°C and the pressure is 35 kg/cm2. The dimensions of the

the tables produced are 40 x 56 cm.

The results obtained are reported in the following table and are average values.

Control 1 2 Density (kg/cnr*) 685 684 687 Flexural strength (N/mrn^) 20.7 20.6 19.4 Tensile strength (N/mm^) 0.74 0.73 0.67 Thickness swelling

in 2 hours (7?) 11.0 7.9 8.6 Absorption in 24 hours (%) 23.5 23.2 23.7 free formaldehyde 14.3 9.5 12.3 (mg/100 g of dry tablet)

Example 3

This example illustrates the effectiveness of monoethylene glycol together with urea as a formaldehyde binder.

Two formulations are prepared: the control without any of the ingredients of the formaldehyde binder fii three

ee-according to the present invention and sample 1 which contains both moeoethylene glycol and urea.

Boards are produced from these two glue formulations and it is also shown here that with the Aegant® formaldehyde resin according to the present invention, boards classified as E2 (control) and boards classified as E1 (sample 1) are obtained with a urea-formaldehyde resin.

The reduction of formaldehyde in this case is 37%.

ha goddess /** amn i Ana pome follows:

ion 1 parts by weight monoethylene glycol 100% 360

urea 1007? 365

water 275

1000

?, 5

The formulations used are as follows:

Check

grams 1 urea-formaldehyde resin 65% 3077 3077 (molar ratio F:U = 1.27:1)

hardener 400 400 (ammonium chloride 15%)

50% paraffin emulsion. 250 250 ammonia 25?Baum? 5

?c-aapiona 1 t />/' &*> g//?>Je. /Q&X 3? uraeus. /ooX'

water 268 & total 4000 4000 gel time in seconds 66 66 Single-layer boards are prepared in the laboratory by spraying each of these formulations onto 25 kg of wood chips. Boards are pressed for 10.9 and 8 seconds/mm. The thickness of the boards is 17.3 mm. The press temperature is 200?C and the pressure is 35 kg/cm2. The dimensions of the boards produced are 40 x 56 mm.

The results obtained are reported in the following table and are average values.

Control l Density (kg/cm3) 685 684 Flexural strength (N/mm2) 20.7 20.2 Tensile strength (N/mm2) 0.74 0.74 Thickness swelling

in 2 hours (%) 11.0 8.6 Absorption in 24 hours (%) 23.5 22.6 Free formaldehyde 14.3 9.0 $mg/l00 g of dried table

Example 4

/J/uybrta, O

This example illustrates the synergistic behavior of d4-tanoethylene glycol and urea.

Tables are prepared from three different formulations: the control in which none of the formaldehyde binder ingredients are used.

nC?Jrx?.

according to the present invention, sample 1 in which both ingredients of the formaldehyde binder of the present invention are employed and sample 2 in which only one ingredient is employed.

It is obvious from the results obtained and reported below that sample 1 containing both ingredients is much more effective than sample 2 containing only one ingredient/|the more effective of the two ingredients?.

The formaldehyde reduction obtained in this case is 32%.

The formulations of the various samples used are as follows:

parts by weight by weight monoethylene glycol 100%

100% urea

waterfall

1000 1000 % of s

"w bvkuiuj.ucji.vui- ui wrwx io uocivc owuv wuiu ocguvuw ? c - lf -\

Control ^ 2 .

grams grams grams

urea-formaldehyde resin 65% (ratio

molar F:U 1,27:1) 3077 3077 3077

Hardener (ammonium

chloride 15%) 400 400 400

paraffin emulsion 50% 250 250 250

Ammonium 25?Baum? 5 5 5

sample?l?- tb/'aphiphiids (SJt

they make 2- area. 40?/? -

water 268 //4 m

total 4000 4000 4000

time of gelifi- 70 71 76

cation in seconds

fairy tales?a layer oingoio are prepared?in 1-abi

ratorio spraying each of these formulations

on 25 kg of wood shavings. Boards are pressed

for 10.9^gd--8-'seconds/min. The thickness of the boards

_

?Pressure ? -3-5- kg/cm^. ? The ? dimensions of the table -produced are?^iQ?x-56 min.-The results obtained are reported in the table which follows are average values.

Control _ 1 _ 2 Density (kg/m^) 688 688 687 Flexural strength (N/mm^) 17.6 17.6 17.5 Tensile strength (N/mm^) 0.55 0.60 0.56 Thickness swelling

in 2 hours (%) 6.7 4.9 4.7 ? Absorption in 24 hours (7?) 20.1 20.1 19.5 free formaldehyde 15.0 10.3 12.3 {mg/100 g dry table}

Po?hJkx.

resin with different molar ratios as well as various levels of addition of the same formaideidium binder.

The formaldehyde binder used has the following formulation:

parts by weight glycerin 1007 270

urea 1007, > 318

water 412

1000

of solids 58^8

5-??-??466*-? J tra / ft > Cas-o 4-B-

'DESCRIPTION of the 1st invention? indua-t-r-ia?-c from ? &4-to 1 o ?; "FORMALDEHYDE BINDER" AND - PROCEDURE FOR PREPARING IT AND - OBTAINING - WITH IT? WOOD PANELS1?1? ?

of the Anti-H-o- olondes-i oil? rE-?????? NTV?

with-? site ? in ? -GURA^AO- (Antil-lc 0 l-and-c-s-ir) -

??ASStFNTO

A formaldehyde binder is described for use in non-cellulosic sheet materials such as particle board, plywood, or plywood, in which a formaldehyde-based adhesive is employed.

The binder comprises an organic hydroxy compound and an amide /?'(?..

DESCRIPTION

Boards such as a ?pntmc-l"lo truoiolorc;? gray and similar are prepared from liguficellulosic materials using adhesives. The preferred adhesives (or glues) are formaldehyde-based such as urea-formaldehyde, mejiimine-formaldehyde, phenol-formaldehyde and phenol-formaldehyde resins or mixtures thereof. It is a well-known fact that boards prepared using these adhesives have a formaldehyde odor which is both harmful and unpleasant. Formaldehyde is added both during the production of such boards

4 ? ? nT*an fwa i 1 I nrn ? mma was 7 rr r? aman oH i mn i oon f ? rt a 1 Postilla 1 of page 18

1. Formaldehyde binders for use on boards prepared from lignocellulosic materials where the adhesive used is formaldehyde-based, such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde, resorcinol-formaldehyde, or mixtures thereof, said formaldehyde binder effectively reduces free residual formaldehyde without reducing the properties of the board, and without requiring any extra operations in the production of particleboard, plywood, or blockboard, and without in any way affecting the reactivity of the system, wherein said formaldehyde binder consists of an organic compound or mixtures thereof containing one or more hydroxyl groups and an amide, or mixtures of various amide(s).

2. The formaldehyde binder of claim 1, wherein the organic compound containing one or more hydroxyl groups may be any one or more of the following: methanol, glycerin, ethylene glycol, dextrose, phenol or resorcinol, etc., and the amide may be any one or more of the following:

urea, thiourea, formamide, acetamide, benzamide, oxamide, succinamide, malonamide, etc.

3. Formaldehyde binder according to the claims

Claims (1)

1-3, In which the ratio of organic compound or mixtures thereof containing one or more hydroxyl groups to one or more amides is 10-200/100 in parts by weight. 6. Formaldehyde binder according to claim 1-4, wherein the preferred ratio of organic compound or mixtures thereof containing one or more hydroxyl groups to one or more amides is 20-150/100 parts by weight. 6. Formaldehyde binder according to claim 1-5, wherein it is added to a glue formulation in amounts of 1 to 10% in the liquid resin, the resin being taken as 657* and the formaldehyde binder taken as 1007.solid. 7. Process for the production of formaldehyde binder according to claims 1-6. 8. Use of a formaldehyde binder according to claims 1-7 in industries where the adhesive is based on formaldehyde such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde, resorcinol-formaldehyde or mixtures thereof for the formation of boards from lignocellulosic materials such as chipboard, plywood, blockboard, etc.