DD232018A5 - FORMALDEHYDBINDING MEDIUM - Google Patents

Abstract

A formaldehyde binding agent is described for use in wood cellulosic sheet materials such as chipboard, plywood or blockboard using a formaldehyde based adhesive. The formaldehyde-binding agent contains an organic hydroxyl compound and an amide.

Description

The invention relates to a formaldehyde binding agent for use in sheets made from wood cellulosic materials using formaldehyde-based adhesives.

Characteristic of the known technical solutions

Sheets such as chipboard and the like are made using adhesives of wood cellulosic materials. The preferred adhesives (or glues) are those based on formaldehyde such as urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde and resorin-formaldehyde resins or mixtures thereof. It is a well-known fact that using these adhesives produced plates have a formaldehyde odor, which is both harmful and unpleasant. Formaldehyde is emitted both during the manufacture of such plates and during their storage and end use.

Many methods for preventing the emission of formaldehyde have been proposed, but they are either either ineffective or worsen the properties of the plates or require complicated application methods. Some of these methods include spraying or coating by brushing the hot plates emerging from the press with various solutions, such as Solutions of urea and / or

^ -3.8 -. 0189711

Ammonia or Ammonium Salts In general, processes of this type are not desirable for industrial use because they require additional process steps and are not very effective anyway.

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 effective. One of their disadvantages stems from the fact that the properties of natural products are not constant.

Another method of reducing free formaldehyde content involves the use of an aqueous suspension of special wax coated urea granules produced by prilling. This method also requires a separate feed line because the product is not added to the adhesive formulation itself ·

Object of the invention

The object of the invention is to provide a formaldehyde-binding agent which effectively reduces the odor of formaldehyde without deteriorating the properties of the plate, without altering the reactivity of the adhesive formulations and without requiring any additional steps in the production of particle board, plywood or blockboard.

Explanation of the essence of the invention

The object of the invention is to provide connections

which have the desired properties as formaldehyde-binding agent.

According to the present invention, there is provided a formaldehyde-binding agent for use in plates made using formaldehyde-based adhesives from cellulosic materials. The formaldehyde-binding agent of the present invention is characterized by being a solution of

(A) at least one organic hydroxyl compound with the exception of monohydric aliphatic alcohols having 1 to 4 carbon atoms and

(b) at least one amide

in water. The formally dehydrating agent may also be (c)

an organic compound which acts as a solvent for (a) and (b) and which also reacts with formaldehyde, and / or (d) a water-soluble inorganic compound. The organic compound (c) is preferably a monohydric aliphatic alcohol having 1 to 4 carbon atoms. The inorganic compound (d) is preferably a hydrogen halide salt. Even if the individual components are insoluble in water, they can dissolve in water when a mixture of them is dissolved in water.

10 water is heated to 70 ⁰ C.

Preferably, the organic hydroxy compounds [component (a)] are soluble in water or in lower monohydric aliphatic alcohols. Examples of such preferred hydroxy compounds are up to 6 carbon atoms containing divalent, trivalent and pentavalent alcohols, up to 6 carbon atoms, monosaccharides containing up to 12 carbon atoms, disaccharides and polysaccharides containing a Ostwald viscosity up to 200 mPas at 25 ⁰ C and at a concentration which corresponds to 37 % refraction. Other examples of preferred hydroxyl compounds are aromatic alcohols and phenols, which are preferably used alone or in combination with one or more of the above-mentioned dihydric, trihydric and / or pentahydric alcohols and / or monosaccharides, disaccharides and / or polysaccharides. The phenols and aromatic alcohols may be monohydric or polyhydric phenols or monohydric or polyhydric aromatic alcohols.

30 Ie containing only one benzene ring.

Specific examples of suitable organic hydroxyl compounds are monoethylene glycol, diethylene glycol, glycerol, pentaerythritol, fructose, mannose, sorbitol,

Dextrose, sucrose, maltose, lactose, dextrin, phenol, resorcinol, hydroquinone and the like.

Preferably, the amides [component (b)] used in the formaldehyde-binding agent of the present invention are also soluble in water or in lower monohydric aliphatic alcohols. Particularly preferred are aliphatic amides containing up to 6 carbon atoms and aromatic amides containing only one benzene ring.

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

If desired, the formaldehyde-binding solubilizing agent of the present invention may further contain additives [component (c)] which are lower monohydric aliphatic alcohols such as methanol, ethanol, isopropanol and the like.

A cheaper and more effective formaldehyde-binding agent is obtained when inorganic compounds [component (d)] are added, which are preferably hydrogen halide salts, especially halides of alkali metals or alkaline earth metals, such as sodium chloride. Potassium chloride and calcium chloride.

The weight ratio of organic hydroxyl compound [component (a) and component (c), if present] and inorganic compound [component (d), if present] to amide [component (b)] is preferably 10: 100 to 400: 100, especially 10: 100 to 200: 100. The novel formaldehyde-binding agent

can the usual glue formulations in amounts of 1 to 10 %, preferably 3 to? ί, to formaldehyde binding agent swelling agents based on the weight of the liquid resin containing 65 weight percent resin solids. be set.

The formaldehyde-binding agent of the 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] , The water content of the formaldehyde-binding agent depends on the solubility of the active ingredients and the amount of water that can be tolerated in the size formulations.

The formaldehyde-binding agent of the present invention can be prepared by simply adding the active ingredients and water to a mixer and mixing until the active ingredients are dissolved. This can be done at room temperature or at an elevated temperature up to 70 ⁰ C.

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

When using the formaldehyde-binding agent of the present invention, it is possible to prepare plates which actually contain less than 10 mg of free formaldehyde per 100 g of the dry plate as determined by the perforator method No. EN 120 of F.E.S.Y.P. (Federation Euro-

peenne of the Syndicate of the Manufacturers de Panneaux de Particules),

The amount of free formaldehyde reduction depends on many factors and can therefore vary within wide limits. If the emission of free formaldehyde is high (higher than 50 mg of formaldehyde per 100 g of the dry plate), the reduction can be high and be 6 % to 85 % . When the emission of free formaldehyde is relatively low, that is, 20 to 50 mg of free formaldehyde per 100 g of the dry plate, the maximum reduction is usually 50 to 60 %. The amount of reduction achieved also depends on the amount of the formaldehyde-binding agent used The more formaldehyde binding agent is used, the lower the amount of free formaldehyde.

When the effective components of the formaldehyde-binding agent are used in combination, the reduction of the free formaldehyde is surprisingly much higher than the sum of the effects of the separate components, and they have no detrimental effect on the responsiveness of the size formulation or the properties of the plates.

embodiment

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

example 1

In this example, the hydroxyl group-containing organic compound is glycerol, and the amide is urea. Here the synergistic behavior of these two compounds is explained. Various glue formulations

are produced and each is then used to make chipboard.

The comparison does not contain any of the components of the "formaldehyde-binding agent" according to the invention.

Sample 1 contains both glycerol and urea, Sample 2 contains only glycerin, and Sample 3 contains only urea.

It can be seen from the tables below that glycerin, when used alone (Sample 2), is a very effective formaldehyde binding agent, while urea (Sample 3) is a poorer formaldehyde reduction and inferior mechanical properties and water resistance results; however, when urea is used in combination with glycerol (Sample 1), values are found equivalent to those achieved with glycerol on its own.

It is therefore possible to use a cheaper and less effective product (urea) and make it react as effectively as a more expensive and effective product (glycerin). The effectiveness relates to the formaldehyde absorption capacity as well as to the maintenance of good mechanical properties and good water resistance without changing the reactivity of the size formulation and without the need to use any special appliance for its use.

30 temperatures to use. '.

In this case, the formaldehyde reduction is indeed 46 %.

The formulations of the various samples used are as follows:

Glycerin ($ 100) Sample 1 Sample 2 Sample 3 5 , Urea (100%) weight weight weight water parts   parts • parts 270 590 - % Solids 320 - 590 410 410 410 10 1000 1000 1000 59 59 59

The glue formulations used are as follows:

Comparison 1 2 3

gggg urea-formaldehyde resin 6535-ig 3077 3077 3077 3077 (molar ratio F: H 1.27: 1)

Hardener 400 400 400 400

(Ammonium chloride

Paraffin emulsion 50 # 250 250 250 250

Ammonia 25 ° Baume 5   - 5 5 - 5 - Sample 1 - 308 308 - .Probe 2 - - - 308 Sample 3 268 -   · - -Mas- · - 30 water 4000 - 4040 4O4O total 68 4040 71 62 Gel time in see 68

Single-layer plates are produced in the laboratory by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10 and 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ^° C.,

and the pressure is 35 kg / cm. The dimensions of the panels produced are 40 χ 56 cm.

The results obtained are summarized in the following table; they are average values.

Comparison 1 '2 .3

Density (kg / m ³ ) 683 669 663 657

Flexural strength (N / mm ² ) 19.9 18.1 17.3 16.3 Tensile strength (N / mm ² ). 0.73 0.72 0.71 0.63 2-hour thickness swelling (%) 5.2 4.9 4.5 5.4

24-hour thickness swelling (%) 51.4 49.9 47.4 53.1

Free formaldehyde 15.8 8.5 8.7 11.7

20 (mg / 100 g dry plate)

This is another example that illustrates the synergistic behavior of glycerine and urea in reducing free formaldehyde in particle board while maintaining the mechanical properties of the boards as well as water resistance.

j The comparison does not contain any of the components of the inventive formaldehyde-binding agent. Sample 1 contains both components of the formaldehyde-binding agent according to the invention, and sample 2 contains only

one of the two components (the most effective of the two components).

Again, it is noted that only sample 5 1 gives a free formaldehyde content which is below 10 mg per 100 g of dry plate (which is the desired value for class E 1), and is the only sample that is absolutely equivalent has mechanical properties and water resistance. The reduction of formaldehyde is actually 34 %.

The formulations of the various samples used are as follows:

Glycerin (100%) Urea (100 #) Water

% Solids

Sample 1 Sample 2 Parts by weight   Parts by weight 128 128 424 - 448 872 1000 1000 55.2 12.8

The glue formulations used are as follows:

Comparison 1 '< gg i

Urea-formaldehyde resin

6556-Ig 3077

(Molar ratio F: H = 1.27: 1)

Hardener (ammonium chloride, 15 $)

Paraffin emulsion 50 # ammonia 25 ° Baume

400

250 5

3077 400th

250

3077 400th

250 5

comparison

Sample 1 - 268

Sample 2 -

Water - 268 - -

Total 4000 4000 4000

Gel time in see 66 67

In the laboratory become single-layered plates

prepared by adding each of these formulations

10 25 kg wood chips sprayed. Plates are at 10, 9

and pressed 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ^° C.,

2 and the pressure is 35 kg / cm.

testified plates are 40 χ 56 cm.

2 and the pressure is 35 kg / cm. The dimensions of the

·

The results obtained are summarized in the following table; they are average values.

Comparison 1 2

Density (kg / m ³ ) 685 684 687

Flexural strength (N / mm ² ) 20.7 20.6 19.4

Tensile strength (N / mm ² ) 0.74 0.73 0.67

2-hour thickness swelling {%) 11.0 7.9 "8.6

24 hour absorption (%) 23.5 32.2 23.7

Free formaldehyde 14.3 9.5 .12.3

(mg / 100 g dry plate)

Example 3

This example illustrates the effectiveness of monoethylene glycol with urea as the formaldehyde binding agent.

Two formulations are prepared: the comparison without any of the constituents of the formaldehyde-binding agent according to the invention and sample I ₃ containing both monoethylene glycol and urea.

Panels are made from these two size formulations, and it is also proved that with the inventive formaldehyde-binding agent using a urea-formaldehyde resin which normally produces plates classified as E 2 (comparative), plates are obtained which are known as E 1 be classified (sample 1).

The reduction of formaldehyde in this case is 37 %.

The formulation of the sample 1 used is as follows:

20 Monoethylene glycol 100% 25 % Solids Sample 1 Urea 100 $ Parts by weight water 360 365 275 1000 72.5

The glue formulations used are as follows:

30. ,

comparison

Urea-formaldehyde resin 65% 3077 3077 (molar ratio F: H 1.27: 1)

5 hardeners 400 400

(Ammonium chloride 15 # -ig)

Paraffin emulsion 50 # ammonia 25 Baume

Sample 1 water Sum of gel time in see

Single-layered plates 15 are prepared in the laboratory by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ⁰ C, and

ρ the pressure is 35 kg / cm.

th plates are 40 χ 5β cm.

250 - 250 VJL 268 5 4000 268 66 - 4000 60

the pressure is 35 kg / cm. The dimensions of the produced

The results obtained are summarized in the following table; they are average values

 25

Density (kg / m ⁵ )

Bending strength (N / mm) -r

2 Tensile strength (N / mm) 2-hour thickness swelling {%) 24-hour absorption {%) Free formaldehyde (mg / 100 g dry plate)

"Comparison 1 685 684 20.7 20.2 0.74 0.74 11.0 8.6 23.5 22.6 14.3 9.0

Example '4

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

Plates are made from three different formulations: the comparison using no components of the formaldehyde-binding agent of the invention, sample 1 using both components of the formaldehyde-binding agent of the invention and sample 2 using only one of these ingredients.

It can be seen from the results obtained, which are presented below, that sample Ij containing both components is much more effective than sample 2, which contains only one component (the most effective of the two components).

The reduction in formaldehyde obtained in this case is 32 %.

The formulations of the various samples used are as follows:

Sample 1 Sample 2

Parts by weight parts by weight

Monoethylene glycol 100% 30 % Solids 230 580 Urea 100 ^ -ig 350 - water 420 420 1000 1000 58 58

The glue formulations are as follows:

comparison

Urea-formaldehyde resin

65% ³ ° ^{77 3O77 3O77}

(Molar ratio P: H = 1.27: 1)

Harder

(Ammonium chloride 15%) 400 400 400

Paraffin emulsion 50 # ammonia 25 Baume sample 1. Sample 2 water Sum Gelzeit in see

Single-layer plates are produced in the laboratory by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates

20 carries 17.3 mm. The temperature of the press is 200 ^° C.,

ρ and the pressure is 35 kg / cm. D produced panels are 40 χ 56 cm.

250 - 250 250 - 5 - 5 5 268 268 268 - 4000 - 4000 70 - 76 4000 71

2 and the pressure is 35 kg / cm. The dimensions of the

The results obtained are summarized in the table below; they are average values.

Density (kg / m)

2 Bending strength (N / mm) Tensile strength (N / mm ² ) 2-hour thickness swelling (%) 24-hour absorption (%) Free formaldehyde (mg / 100 g dry plate)

comparison 1 2 688 688 f 687 17.6 17.6 17.5 0.55 0.60 0.56 6,7 4.7 20.1 20.1 19.5 15.0 10.3 12.3

Example · 5

In this example, the use of a resin having a different molar ratio as well as various addition amounts of the formaldehyde-binding agent itself will be explained.

The formaldehyde-binding agent used has the following formulation:

10 Glycerin 100 $ parts by weight Urea 100 ^ -ig 270 water 318 412 % Pesticides 1000 15 58.8

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

Comparison 12 3

g gg g

Urea-formaldehyde resin 65% ± s (molar ratio 3077 3077 3077 3077 ratio F: H = 1.4: 1)

Hardener " 293 380 380 380

(Ammonium chloride 15%)

Paraffin emulsion 50% 250 ammonia 25 ° tree 5

Formaldehyde binding agent 30 water 375

Sum 4000

Gel time in see 73

In the laboratory become single-layered plates

250 250 250 5 5 5 154 215 375 134 73 - 4000 4000 4087 73 72 75

prepared by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ^° C. and the pressure is 35 kg / cm. The dimensions of the panels produced are 40 χ 56 cm.

The results obtained are summarized in the following table; they are average values.

Density (kg / nr) Bending strength (N / mm) 15 Tensile strength (N / mm) 2 Hour thickness swelling (%) 24-hour thickness swelling ^r Free formaldehyde (mg / 100 g dry board)

It is stated that the mechanical

Properties and the water resistance of the plates are equivalent and that the reduction of the formaldehyde

Hyds 41 % in the case of sample 1, 55 % in the case of sample and 57 % in the case of sample 3.

Example 6

In this example, six different types of polyhydric alcohols, two different types of amides, a single additive, and various ratios of alcohol to amide, ranging from 57.5 / 100 to 385/100 are illustrated.

The various types of formaldehyde-binding agents used are as follows:

comparison 1 2 3 680 687 685 688 22.0 22.5 22.3 21.6 0.61 0.63 0.66 0.64 (*) 10,1 9.3 8.8 9.5 {%) 20,6 21.8 21.0 • 21.5 22.2 13.0 10.1 9.5

Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample .6

dextrose 230 - - - - - diethylene glycol - 330 - - - - monoethylene glycol - 260 - - 110 glycerin - 500 - -. , sucrose - - - - - 110 sorbitol - - - l40 - methanol - - 200 - l40 80 urea 400 300 - 130 350 330 thiourea - - 170 - - - water 370  370 370 370 370 370 total 1000 1000 1000 1000 1000 1000 % Pesticides 63 63 63 63 63 63 Weight ratio alcohol / amide 57.5 / 100 110/100 270/100 385 / IOO 80/100 91/100

- 19 All numbers mentioned above are parts by weight.

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

comparison - 1 2 3 4 5 6 G - G G G G '' g '' ' G Urea-formaldehyde resin 3077 - 3077 3077 3077 3077 3077 3077 65% (molar ratio P: H = - 1.27: 1) - Harder 400 - 500 500 500 500 500 500 (Ammonium chloride, 15% 268 Solution) 4000 Paraffin emulsion 50 $ 250 65 25O 25O 250 250 250 250 Ammonia 25 ° Baume 5 - - , - - - - Formaldehyde binding agent Sample 1 307 - - - - - Sample 2 - 307 - -   - - Sample 3 - - 307 - - - Sample 4 - - - 307 - - Sample 5 - - - - 307 - Sample 6 - - - - - 307 water - - - - - total 4134 4134 4134 4134 4134 4134 Gel time in see 66 65 67 66 62 69

- 21 -

Single-layered plates are prepared in the laboratory by spraying each of these formulations on 25 kg wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ^° C.,

ρ and the pressure is 35 kg / cm. D:

produced panels are 40 χ 56 cm.

2 and the pressure is 35 kg / cm. The dimensions of the

The results obtained are summarized in the following table; these are average values:

comparison 1 2 3 4 5 6. ... 688 689 687 685 690 685 692 19.6 19.5 18.3 19.5 20.1 19.3 19.4 0.71 0.69 0.67 0.73 0.7 ** 0.72 0.70 7.0 6.5 5.0 5.5 6.1 6.5 6.2 ) 19.7 19.3 20.0 19.8 19.5 20.1 19.9 16.1 8.9 8.6 11.0 9.0 9.8 8.5

Density (kg / nr) Bending strength (N / mm) Tensile strength (N / mm) 2-hour thickness swelling (%) 24-hour swelling (%) Free formaldehyde (mg / 100 g dry plate)

Formaldehyde reduction {%) - 45 47 32 44 39 4'7

The results summarized above demonstrate that all the samples used give values equivalent to the comparison, while the reduction in formaldehyde is on the order of 32 to 47 % .

Example 7

In this example, three different types of hydroxyl-containing organic compounds, namely dextrin, phenol and resorcinol are used.

A monohydric alcohol which acts as an additive and is different from methanol is also explained, namely ethyl alcohol.

The various types of formaldehyde-binding agents used are as follows:

Sample 1 Sample 2 Sample 3 Sample 4

monoethylene glycol 230 - - - dextrin - l40 - - phenol - - 130, - resorcinol - - - 130 methanol - 140 130 130 ethanol 80 - - - urea 350 350 370 370 water 340 370 370 370 1000 * 1000 1000 1000 % Solids 66 63 63 63

All figures above are parts by weight. The samples of formaldehyde binding agents are used in this example to form part of the

used resin to replace.

The glue formulations used are as follows:

Comparison 1 2 3 ¹ ^

g g g g

Urea-formaldehyde 3077 2770 2770 2770 2770 resin (molar ratio F: H = 1.27: 1)

Hardener 400 500 400 450 400

(Ammonium chloride, 15% solution)

Paraffin emulsion 50 # 250 250 250 250 250

15 ammonia 25 trees 5

Formaldehyde binding agent

Sample 1 - 307

Sample 2 307

Sample 3 - 307

Sample 4 '- - - - 307

Water · 268

Total 4000 3827 3727 3777 3727

Gel time in see 65 64 62 63 63

Single-layer plates are produced in the laboratory by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm.

The temperature of the press is 200 ⁰ C, and the pressure is 35 kg / cm 'are 40 χ 56 cm.

2 is 35 kg / cm. The dimensions of the pressed plates

The results are summarized in the following table; they are average values.

comparison 1 2 3 .4 702 698 695 705 710 20.1 19.5 19.7 20.0 20.8 '0.75 0.70 , 0.75 0.73 0.72 7.1 6.8 6.5 6.3 6.6 20.3 21.5 21.3 21.8 21.3 13.1 9.6 9.2 8.2 10

Density (kg / m ⁵ )

ο bending strength (N / mm)

Tensile strength (N / mm ² ) 2-hour thickness swelling (%) 24-hour thickness swelling (%) Free formaldehyde (mg / 100 g dry plate)

Formaldehyde reduction (50 27 30 37 24 rv>

- 2β -

The results given above demonstrate that all samples have values equivalent to those of comparative sample j containing no formaldehyde-binding agent, although the latter replaces an equivalent amount of urea-formaldehyde resin in the other formulations. The reduction of formaldehyde varies from 24 to 37 % in this example .

Example 8

In this example, only one type of formaldehyde-binding agent is used, and the resin is a phenol-melamine-urea-formaldehyde resin.

The formaldehyde-binding agent used has the following formulation:

parts by weight

Monoethylene glycol 300

Urea 330

Water · 370

20 1000 '

The glue formulations used are as follows:

Comparison 1

Phenol-melamine-urea

Formaldehyde resin 63% 5600 5600

Hardener (15,5 ^ -ige aqueous

Ammonium chloride) 840 840 Paraffin emulsion 50% 150 150 Formaldehyde binding agent - 56Ο total 6590 7150 Gel time in see 73 79

Single-layer plates are produced in the laboratory by spraying each of these formulations on 25 kg of wood chips. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press, is 200 ⁰ C,

2 and the pressure is 35 kg / cm. The dimensions of the

produced plates are 40 χ 56 cm.

comparison · ··· 705 695 26.2 25.9 0,27- 0.26 2.7. 2.6 7.1 6.2 12.0 11.3 12.8 7

The results are summarized in the following table; they are average values. '.

Density (kg / m ³ )

15 flexural strength (N / mm)

Tensile strength (N / mm)

Tensile strength Vloo (N / mm ²⁾ 2 Hour thickness swelling (%) 24-hour thickness swelling {%) 20 Free formaldehyde (mg / 100 g dry board)

Formaldehyde reduction {%) - 45

The above results prove that the formaldehyde-binding agent of the invention can also be used for phenol-melamine-urea-formaldehyde resins and considerably reduces the emission of free formaldehyde without adversely affecting the properties of the plates

 ,

Example 9

In this example, the 'formaldehyde-binding agent used contains an inorganic compound'

[Component (d)], which in this case is sodium chloride.

The formaldehyde-binding agent used has the following formulation:

parts by weight Monoethylene glycol 100% 270 Urea 100 ^ -ig 318 10 sodium chloride 100 # -ig 50 water 362 - total 1000 % Pesticides 63.8

15 The ones used in the different samples

Glue formulations are as follows:

Comparison 1

20 urea-formaldehyde resin 3077 2770 (molar ratio F: H = 1.27: 1)

Harder 400 - 450 (Ammonium chloride, 15%) 268 Solution) 4000 - 25 paraffin emulsion 50 # -ig 250 65 250 Ammonia 25 trees 5 - Formaldehyde binding agent 307 water - total 3777 30 gel time in see 64

In the laboratory, single-layered plates are prepared by placing each of these formulations on

25 kg wood chips sprayed. Plates are pressed at 10, 9 and 8 seconds / mm. The thickness of the plates is 17.3 mm. The temperature of the press is 200 ^° C.,

and the pressure is 35 kg / cm. :

pressed plates are 40 χ 56 cm.

and the pressure is 35 kg / cm. The dimensions of the

comparison   ··] _ 695 699 19.9 19.5 0.71 0.73 7.0 6.6 20.5 20.8 17 9.5

The results obtained are summarized in the following table; they are average values

 10

Density (kg / m ³ )

Bending strength (N / mm)

2 tensile strength (N / mm)

15 2-hour thickness swelling

24-hour thickness swelling (%) Free formaldehyde (mg / 100 g dry plate)

Formaldehyde reduction {%) - 44

The results demonstrate that the sample containing the formaldehyde-binding agent gives values equivalent to those of the control, despite the fact that the formaldehyde-binding agent replaces part of the urea-formaldehyde resin in the formulation. The reduction of formaldehyde is 44 %.

Claims (28)

- 30 -. , invention claim 1 to 4 carbon atoms is soluble · A formaldehyde binding agent for use in sheets made from wood cellulosic materials using formaldehyde-based adhesives, characterized by being a solution of (A) at least one organic hydroxyl compound with the exception of monohydric aliphatic alcohols having 1 to 4 carbon atoms and (b) has at least one amide in water 2. Formaldehyde-binding agent according to item 1, characterized in that it additionally contains (c) an organic compound which acts as a solvent for (a) and (b) and also reacts with formaldehyde * Formaldehyde-binding agent according to item 2, characterized in that component (c) is a monohydric aliphatic alcohol having 1 to 4 carbon atoms. 4 · Formaldehyde-binding agent according to one of the items 1 to 3, characterized in that it also contains (d) a water-soluble inorganic compound. 5 · formaldehyde-binding agent according to item 4 », characterized in that component (d) is a water-soluble hydrogen halide salt # Formaldehyde-binding agent according to item 5, characterized in that component (d) is a water-soluble halide of an alkali metal or an alkaline earth metal. 7. Pormaldehyde-binding agent according to item 6, characterized in that component (d) is sodium chloride, potassium chloride or calcium chloride. 8. Pormaldehyde-binding agent according to one of the items 1 to 7 »characterized in that the component (a) in water or in a monohydric aliphatic alcohol with Pormaldehyde-binding agent according to item 8, characterized in that component (a) comprises dihydric, trihydric 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 to 200 mPas at 25 ⁰ G and a concentration corresponding to 37 % refraction is selected · Pormaldehyde-binding agent according to item 8, characterized in that component (a) is selected from aromatic alcohols and phenols. 11. Pormaldehyde-binding agent according to item 10, characterized in that component (a) is selected from monohydric and polyhydric aromatic alcohols containing only one benzene ring and monohydric and polyhydric phenols. Pormaldehyde-binding agent according to one of the items 1 to 11, characterized in that component (b) is soluble in water or in a monohydric aliphatic alcohol having 1 to 4 carbon atoms. 13, characterized in that the weight ratio of component (a) plus components (c) and (d), if present, to component (b) is 10: 100 to 400: 100. 13. Pormaldehyde binding agent according to item 12, characterized in that component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing only one benzene ring. 14, characterized in that it contains 20 to 80% by weight of the active ingredients. 14 · Formaldehyde-binding agent according to one of the items 1 to 15 · Formaldehyde-binding agent according to one of the items 1 to 16 · Process for the preparation of the formaldehyde-binding agent according to item 1, characterized in that (a) at least one organic hydroxyl compound with the exception of monohydric aliphatic alcohols having 1 to 4 carbon atoms, (b) at least one amide as well (C) optionally at least one organic compound, (V) which acts as a solvent for (a) and (b) and also reacted with formaldehyde, and (d) optionally, a water-soluble inorganic compound and water at a temperature of room temperature to 70 ⁰ G mixed. Process according to item 16, characterized in that the component (c) used is a monohydric aliphatic alcohol having 1 to 4 carbon atoms. Process according to item 16 or 17 », characterized in that a water-soluble hydrogen halide salt is used as component (d). Process according to item 18, characterized in that a water-soluble halide of an alkali metal or a bridging alkali metal is used as component (d) Method according to item 19, characterized in that sodium chloride, potassium chloride or calcium chloride is used as component (d). Process according to any one of items 16 to 20, characterized in that component (a) is soluble in water or in a monohydric aliphatic alcohol containing from 1 to 4 carbon atoms. 22. The method according to item 21, characterized in that the component (a) from containing up to 6 carbon atoms dihydric, trihydric and pentavalent alcohols, up to 6 carbon atoms containing mono sacchari containing up to 12 carbon atoms Di sacchari the and polysaccharides, chosen with an Ostwald viscosity up to 200 mPas at 25 ⁰ G and a concentration corresponding to 37% refraction is · 23 »Process according to item 21, characterized in that component (a) is chosen from aromatic alcohols and phenols» ^ -, 24 * Process according to item 23 », characterized in that component (a) is selected from monohydric and polyhydric aromatic alcohols containing only one benzene ring and monohydric and polyhydric phenols. Method according to one of the items 16 to 24 »characterized in that component (b) is soluble in water or in monohydric aliphatic alcohols having 1 to 4 carbon atoms. Process according to item 25 »characterized in that component (b) is selected from aliphatic amides containing up to 6 carbon atoms and aromatic amides containing only one benzene ring. Process according to any one of items 16 to 26, characterized in that the weight ratio of component (a) plus components (c) and (d), if present, to component (b) is 10: 100 to 400: 100. Process according to one of the items 16 to 27, characterized in that the formaldehyde-binding agent contains from 20 to 80% by weight of the active constituents.