CS225416B1 - Modified ureaformaldehyde adhesive - Google Patents

Abstract

Modified urea-formaldehyde glue to reduce development curing formaldehyde containing glue and modifiers from the group thermodynamically unstable compounds nitrogen, especially aliphatic and aromatic azo compounds, hydrazides, organic azides, nitro and nitro-zoamines, ammonium salts of carbonic acid a derivatives.

Description

The present invention relates to a modified urea-formaldehyde adhesive for gluing woody materials, in particular wood-chipboard and fibreboard, veneer, plywood, cardboard, paper and the like, wherein the modifier wins are selected such as to reduce formaldehyde evolution during curing and favorably affect the physical Indicators and Adhesive Consumption ·

The reaction of formaldehyde with urea in a basic environment in the process of producing urea-formaldehyde adhesives produces not only methylol urea derivatives, but also, to a lesser extent, intermolecular etheric bridges (actually derivatives of Ν, ΙΤ * -disubstituted alpha, beta-diaminodimethyl ether). in the process of gluing with them, the etiocyte binders are broken down to form formaldehyde and methylen urea derivatives · The released formaldehyde remains in the cured adhesive and diffuses into the environment over time, thus contributing to environmental pollution ·

It should be noted that in the production of particle board bonded with urea-formaldehyde adhesives, the amount of formaldehyde released is in the range of 30 to 50 mg per 100 g of absolute dry particle board.

225 416 (according to the internationally valid FESIP method). In the manufacture of some of these particle board products, but especially in their application in wood melts, the release of formaldehyde released into the air exceeds the permitted standards, which considerably limits the use of particle board.

Reducing formaldehyde leakage into the dock environment is a worldwide trend · In the case of chipboard glued with urea-formaldehyde adhesives, the prevention or reduction of this leakage is achieved by veneer or plate coating, or by exposure to ammonia atmosphere. , melaain or phenol ormaldehyde or isocyanate resins and, in addition to the urine x formaldehyde adhesive, are not very effective and also not economically advantageous.

In the case of permanent environmental protection requirements, in the case of particle boards glued with urea-formaldehyde adhesives, it is necessary to guarantee a maximum formaldehyde content * of 10 mg per 100 g of total thatched dry matter. The achievement of this goal is possible in the following ways. By realizing such technological changes in the process of producing urea-formaldehyde adhesives so as to guarantee a very low content of etheric intermolecular moieties, but this is nowadays an almost unrealizable requirement. The reduced ratio of formaldehyde to urea results in adhesives with reduced adhesiveness, thereby deteriorating the mechanical properties of the glued joints (products).

Due to the fact that the adhesive capacity of the adhesive is proportional to its volume, compensation for the deteriorated properties of urea-formaldehyde adhesives with a reduced molar ratio of formaldehyde is achieved by applying an increased amount of adhesive to the adhesive and / or by spiking the adhesive. The addition is carried out by adding fillers (eg cellulose, flour, gypsum, etc.),

225 416 in addition to deteriorating the mechanical properties of the joint, or by foaming with air using emulsifiers. By applying air as a physical blowing agent despite the lower filling stability during processing, the mechanical properties of the joint are preserved * One way, as already indicated, is to add a urea-formaldehyde adhesive such that the released formaldehyde reliably and reliably binds *

Some disadvantages of known modified urea-formaldehyde adhesives are solved by the present invention.

According to the present invention, a modified urea-formaldehyde adhesive, providing reduced formaldehyde curing development, comprising an adhesive mixture and disodifiers is that the modifiers are thermodynamically unstable nitrogen compounds, in particular aliphatic and aromatic azo compounds, acid hydrazides, orange azides. , nitro and nitrosoamines, ammonium salts of carbonic acid and derivatives thereof, preferably azodiisobutyronitrile, azodicyclohexyl cyanide, azodicarbonamide, diazoaminobenzene, 1,5-endomethylene-3,7-dinitroso-1,3,5,7-tetraazaoyclooktane, 1,3 5-trinitroaso-1,3,5-triazacyclohexane, N, N'-dimethyl-Ν, Ν'-dinitrosoterephthalamide, dinitro-tetrahydroimidazo (η 5 -d) imidazole-2,5- (1H, 3H) -diones , benzosulfohydrazide, aminoguanidine sulfate, terephthalic azide, biphenyl-4,4'-disulfazide, azidoethanol nitrate, sym-tetraazidobenzoquinone, nitroguanidine, ammonium carbonate nitromates, ammonium carbamate, singly or in mixtures with each other, and / or thermodes Namely unstable mixtures of individually stable substances, preferably equivalent to a molar mixture of calcium nitrites and ammonium sulphate or biruetate and ureas, in an amount of 0.1 to 25.0% by weight, preferably in an amount of 1.2 to 20 % By weight of the adhesive composition

The advantage of the present invention is to achieve a substantial reduction of the formaldehyde released, especially in the production of particle board, below 10 mg of free formaldehyde per 100 g of absolutely dry thatch.

- 5 225 416

FESIP). For the application of the particle board thus produced in wooden constructions, this means that the environmental protection requirements are met without the need for special surface treatment of the boards, thus further reducing costs compared to some of the previously known and used methods. Reducing the release of formaldehyde in chipboard means expanding their area of use, secondary to increasing waste utilization in the wood industry and increasing its economic efficiency. · Modifiers used are commonly available chemical technology products and are applied without the need for special equipment or energy consumption. · It is important to achieve a stable napenenx of urea-formaldehyde adhesive in the process of its thermal exposure. The pressure of the gaseous decomposition products of the modifier (thermodynamically unstable substance) contributes significantly to increasing the adhesive capacity of the adhesive. As a result, the above results not only reduce the consumption of urea-formaldehyde adhesive in the gluing process, but also improve the physico-mechanical properties of the adhesive "bond strength" and elasticity ·

As thermodynamically unstable nitrogen compounds, those which, by thermolysis at a temperature range of 7 ° C to 15 ° C, can be applied within the meaning of the present invention to produce amino radicals that are potentially free acceptors of free formaldehyde. but thermolysis which is associated with an increase in the flexibility of the sp-electrons of their amine nitrogen. In particular, blowing agents commonly used in the plastics and rubber industries, as well as certain substances in the explosives field, have proved to be suitable.

The effect of the invention is further elucidated by the following examples, which are not to be limited or exhausted.

225 416

Example 1

The adhesive mixture is prepared by mixing 125 volumes of mono-formaldehyde glue, 2.5 volumes. parts by volume of 15% ammonium chloride solution, 15 vol. parts of paraffin emulsion beta and 46 vol. water parts ·

The adhesive mixture is dosed by dosing the chipboard containing 4.2% by weight of moisture in an amount of 13 parts by weight of the adhesive mixture to 90 parts by weight of the particle board. The mass produced is molded in a known manner into a carpet, which is pre-pressed at normal temperature and then pressed for 6 minutes at 120 ° C. · The resulting particle board corresponds to the series product and has the following parameters:

Bending strength / MPa / 17.1

Strength 'perpendicular to thatch plane / MPa / 0.4

Specific gravity / kg.m ^J / 780.0

Formaldehyde released / mg per 100 g thatch / 27.1

Example 2

K 100 wt. 15 parts by weight of azodiisobutyronitrile (i.e. 15% by weight of the adhesive mixture) are added to the adhesive mixture as in Example 1. After homogenization, the procedure of Example 1 is followed, except that 8 parts by weight are metered in. Adhesive compound for 90 parts · Particleboard · The following parameters are specified for the resulting chipboard:

Bending Strength / MPa / 17 »δ Strength ´ Perpendicular to thatch Plane / MPa / 0,4 Specific Gravity * /kg.m^/ 720,0 Formaldehyde released / mg per 100 g Thatch / 7» 9

- 7 Example 3

225 416

Κ 100 parts by weight of the adhesive mixture, as in Example 1, is added 8 parts by weight of azodicyclohexyl cyanide (i.e. 8% by weight). After homogenization, the procedure is as described in Example 1, except that 90 parts by weight of the particleboard are dosed with 10 parts by weight of the adhesive mixture with the additive.

Bending Strength / MPa / 18.3 Strength 'perpendicular to thatch plane / MPa / 0.5 Specific Gravity' /kg.m^/ 700.0 Formaldehyde released / mg per 100 g Thatch / 8.0

Example 4

To 100 parts by weight of the adhesive composition, as in Example 1, 5 parts by weight are added. parts of azodicarbonamide (i.e. 5% by weight). After homogenization, the procedure of Example 1 is followed, except that 90 wt. 10 parts by weight of chipboard are dosed. The parts of the adhesive mixture and the pressing are carried out at a temperature of 150 ° C for 7 minutes. For the resulting chipboard, the following parameters are specified:

Flexural strength * / MPa / 19, ^ Strength ´ perpendicular to thatched plane / MPa / 0,6 Specific weight ´ /kg.m”^/ 7 ^ 0,0 Formaldehyde released / mg per 100 g of thatch / 9 »2

Example 5

K 100 wt. 4.2 parts by weight of the adhesive mixture, as in Example 1, are added. % of diazoaminobenzene (i.e., 4.2 wt. weight of adhesive mixture. After homogenization, the procedure of Example 1 is followed, except that 9 parts by weight of the particle board are dosed at 90 parts by weight. The parts of the adhesive mixture and the pressing are carried out at a temperature of 140 ° C

22S 416 for 7 minutes. For the resulting chipboard, the following parameters are set:

Bending Strength / MPa / 17.9 Strength 'Perpendicular to thatch Plane / MPa / 0.5 Specific Gravity' /kg.m'^/ 740.0 Formaldehyde released / mg per 100 g Thatch / 7.6

Example 6

To 100 parts by weight of the adhesive mixture, as in Example 1, is added 3 > 8 parts by weight of 1,5-trimethylene-3,7-aminotroso-1,3,5,7-tetraazacyclooctane (i.e. $ 3.8). % by weight of the adhesive mixture. After homogenization, the procedure of Example 1 is followed, except that 9 parts by weight of the wood chips are dosed for 90 parts by weight. The parts of the adhesive mixture and the molding are carried out at a temperature of 140 ° C for 7 days.

Bending Strength / MPa / 18.1 Strength 'Perpendicular to thatch Plane / MPa / 0.5 Specific Gravity' /kg.rn*^/ 720.0 Formaldehyde released / mg per 100 g Thatch / 9.1

Example 7

To 100 parts by weight of the adhesive mixture, as in Example 1, 2.0 parts by weight of N, 1β-dimethyl-N, N ^, N-di-nitro-terephthalamide (i.e. 2% by weight of the adhesive mixture) are added. After homogenization, the procedure of Example 1 was followed, except that 90 wt. 11 parts by weight of chipboard are dosed. parts of the adhesive mixture with the additive. For the resulting chipboard, the following parameters are specified:

Bending Strength / MPa / 17 »9 Strength 'perpendicular to thatch plane / V & a / 0.5 Specific Gravity' /kg.m”·^/ 770.0 Formaldehyde released / mg per 100 g Thatch / 8.5

- 9 Example 8

225 416

To 100 parts by weight of the adhesive mixture, as in Example 1, 18 parts by weight of benzosulfohydrazide (18% by weight of the adhesive mixture) are added. After homogenization, the procedure of Example 1 is followed, except that for 90 parts by weight of particle board, 10 parts by weight are dosed. parts of the adhesive mixture with the additive and the molding is carried out at a temperature of 140 ° C for 7 minutes.

Flexural strength / MPa / 17.2 Strength perpendicular to thatched plane / MPa / 0.4 Specific gravity / kg.m ³ / 760.0 Formaldehyde released / mg per 100 g of thatch / 7.1

Example 9

To 100 parts by weight of the adhesive composition, as in Example 1, 3.5 parts by weight of terephthalazide (i.e. 3.5% by weight) are added. After homogenization, the procedure of Example 1 is followed, except that 90 wt. 9 parts by weight of particle board are dosed. parts of the adhesive mixture with the additive. The resulting particle board has the following parameters:

Flexural strength / MPa / 17.3 Strength perpendicular to thatched plane / MPa / 0.5 Specific gravity / kg.m ³ / 730.0 Mentioned formaldehyde / mg per 100 g of thatch / 9.0

Example 10

K 100 wt. 12 parts by weight of the adhesive mixture, as in Example 1, are added. parts of ^{4,4-biphenyl,} -disulfazidu / a is 12% by weight. % by weight of the adhesive mixture. After homogenization, the procedure of Example 1 was followed except that 90 wt. 8 parts by weight of particle board are dosed. parts of the adhesive mixture and the pressing is carried out at a temperature of 130 ° C for up to 6 minutes. The resulting chipboard shows found10

225 416 parameters:

Bending strength / MPa / 18.1

Strength * perpendicular to thatch plane / MPa / 0.5

Speific mass * /kg.m to ^/ 700.0

Formaldehyde released / mg per 100 g of thatch / 7.8

Example 11

To 100 parts by weight of the adhesive mixture, as in Example 1, 20 parts by weight of aminoguanidine dicarbonate (i.e. 20% by weight of the adhesive mixture) are added. After homogenization, the procedure of Example 1 is followed, except that 10 parts by weight of the adhesive mixture are dispensed per 90 parts by particleboard and pressed at a temperature of 150 ° C for 7 minutes. The resulting particle board exhibits the following parameters:

Bending Strength / MPa / / 17.6 Strength 'Perpendicular to Thatched Plane / MPa / 0.4 Speific Weight' /kg.m”^/ 760.0 Formaldehyde Released / mg per 100 g Thatch / 6.9

Example 12

To 100 parts by weight of the adhesive mixture, as in Example 1, 20 parts by weight of ammonium carbamate (i.e. 20% by weight of the adhesive mixture) are added. After homogenization, the procedure of Example 1 is followed, except that that 90 parts by weight of particle board add 10 parts by weight of adhesive mixture with an additive * The resulting particle board has the following parameters:

Bending Strength * / MPa / 18.7 Strength 'perpendicular to thatch plane / MPa / 0.5 Speific Weight' /kg.m'^ 690.0 Mentioned formaldehyde / mg per 100 g of thatch / 6.8

- 11 Example 13

225 416

Κ 100 parts by weight of the adhesive mixture, as in Example 1, 2.6 parts by weight of nitroguanidine and 1.7 parts by weight of ammonium carbonate (i.e. 2.6% by weight and 1.7% by weight) are added. After homogenization, the procedure of Example 1 is followed, except that 90 wt. 11 parts by weight of adhesive mixture with additives are dosed. The resulting particle board exhibits the following parameters:

Flexural strength / MPa / 17.9 Strength perpendicular to thatched plane / MPa / 0.3 Specific gravity / kg.m ^J / 740.0 Formaldehyde released / mg per 100 g thatched / 8.4

Example 14

To 100 parts by weight of the adhesive mixture, as in Example 1, 7 parts by weight of 1,3,5-trinitroso-1,3,5-triazacyclohexane (i.e. 7% by weight) are added. weight of adhesive mixture.

After homogenization, the procedure of Example 1 is followed, except that 90 wt. 10 parts by weight of chipboard are dosed. parts of the adhesive mixture with the additive. The resulting particle board has the following parameters:

Bending Strength / MPa / 18.0 Strength 'Perpendicular to thatch Plane / MPa / 0.5 Specific Gravity' /kg.m”^/ 760.0 Formaldehyde released / mg per 100 g Thatch / 8.9

Example 15

K 100 wt. 4.3 parts by weight of the adhesive mixture, as in Example 1, are added. parts of nitro-urea and 1.2 parts by weight of ammonium carbonate (i.e. 4.3% by weight and 1.2 parts by weight of the adhesive composition). The procedure of Examples 1 and 13 is as follows: The resulting particle board exhibits the following parameters:

- 22S 416.

Flexural strength * / MPa /

Strength * perpendicular to thatched plane / MPa / Specific gravity * /kg.m”^/

Formaldehyde released / mg per 100 g of thatch /

18.1

0.5

710.0

9.2

Example 16

To 100 parts by weight of the adhesive mixture, as in Example 1, 3.7 parts by weight are added. parts of azidoethanol nitrate (i.e., 3.7% by weight of the weight of the adhesive mixture). After homogenization, the procedure of Example 1 is followed, except that 90 parts by weight of particleboard are dosed with 9% by weight. parts of the adhesive mixture with the additive. The resulting chipboard exhibits the following parameters:

Bending strength / MPa / 18.4

Strength 'perpendicular to thatch plane / MPa / 0.5

Specific. weight ’/kg.m·^/ 730.0

Formaldehyde released / mg per 100 g of thatch / 8.7

Example 17

K 100 wt. 1.8 parts by weight of the adhesive mixture, as in Example 1, are added. parts by weight of sym-tetraazidobenzoquinone (i.e. 1.8% by weight). After homogenization, the procedure is as described in Example 1, except that 90 wt. 11 parts by weight of the particle board are dosed. parts of the adhesive mixture with the additive. The resulting chipboard exhibits the following parameters;

Bending strength / MPa / 17.9

Strength 'perpendicular to thatch plane / MPa / 0.4

750.0

8.8

Example 18

K 100 wt. 9 parts by weight of the adhesive mixture, as in Example 1, are added. parts of the equimolar mixture of calcium nitrite and ammonium sulphate (i.e. 9% by weight of 1 epi of the target mixture). 10 parts by weight of chipboard are dosed. parts of the adhesive mixture with the additive · Resulting chipboard shows the following parameters:

Bending Strength / MPa / 17.6 Strength Perpendicular to thatch Plane / 4lPa / 0.5 Speocyte Weight ´ /kg.m”^/ 730.0 Released formaldehyde / mg per 100 g Thatch / 8.4

Example 19

To 100 parts by weight of the adhesive mixture, as in Example 1, 1.8 parts by weight are added. parts by weight of an equimolar mixture of biuret and urea and 1.2 wt. % of diazoaminobenzene (i.e. 1.8 wt. and 1.2 wt. The weight of the adhesive mixture / < tb > ______________________________________ < tb > 9 parts by weight of chipboard are dosed. parts of the adhesive mixture and the compression molding is carried out at a temperature of 140 DEG C. for 7 minutes. For the resulting chipboard, the following parameters are specified:

Bending Strength / MPa / 17.8 Strength 'Perpendicular to thatch Plane / MPa / 0.5 Speocyte Weight' /kg.m”^/ 750.0 Released formaldehyde / mg per 100 g Thatch / 8.3

Example 20

Up to 100 wt. 1.2 parts by weight of the adhesive composition of Example 1 are added. by weight of ammonium carbonate and 3.8 wt. % of 4,4'-bis (hydrazosulfonyl) -diphenyloxide (1.2 wt.%). and 3.8 wt. The weight of the adhesive mixture / · After homogenization, proceed as in Example 1 and Example 8 ·

For the resulting chipboard, the following parameters are specified:

225 416

Bending strength / MPa /

Strength 'perpendicular to thatch plane / MPa / Speoifical weight' /kg.m**^/

Formaldehyde released / mg per 100 g of thatch /

17.4

0.5

750.0

7.0

Example 21

To 100 parts by weight of the adhesive composition as in Example 1, 1.8 parts by weight of an equimolar mixture of biruet with urea and 1.2 parts by weight of diazoaminobenzene (i.e. $ 1.8 and 1.2% by weight) are added. weight of adhesive mixture. The resulting particle board exhibits the following parameters:

Bending strength / MPa / 17.8

Strength * perpendicular to thatch plane / MPa / 0.5

Specific gravity ´ /kg.ra'^ 730.0

Formaldehyde released / mg per 100 g of thatch / 8.8

Example 22

Up to 100 wt. 1.2 parts by weight of the adhesive composition of Example 1 are added. by weight of azodicarbonamide, 1.2 wt. by diazoaminobenzene and 1.6 by weight of ammonium carbamate (i.e.

1.2%, 1.2% and 1.6% by weight of the adhesive composition. The procedure of Example 1 is followed, except that 9 parts are applied to 90 parts by weight of particleboard. parts of the adhesive mixture with the additive. Pressing is carried out for 6 minutes at 150 ° C. The resulting chipboard exhibits the following parameters:

Flexural strength * / MPa / 18.0

Strength 'perpendicular to thatch plane / MPa / 0.5

730.0

8.4

Example 23

225 416

Up to 100 parts by weight of the adhesive composition as in Example 1,

coated on chipboard containing 4.1 wt. 12 parts by weight of the mixture to 90 parts by weight of chipboard. The resulting material is formed into a carpet which is pre-pressed at normal temperature and then pressed at 120 ° C for 5 minutes. The resulting particle board exhibits the following parameters:

Bending strength / MPa / 18.1

Strength kol perpendicular ^ to thatch plane / MPa / 0.5

Specific gravity * /kg.m’^/ 710.0

Formaldehyde released / mg per 100 g thatch / 8.0

Claims (1)

OBJECT OF OUT / CLOSE 225 416 The modified urea-formaldehyde adhesive, providing reduced formaldehyde evolution during curing, comprises an adhesive composition and diffusers, characterized in that thermodynamically unstable nitrogen compounds, in particular aliphatic and aromatic azo compounds, hydrazides of acids, or hydrazides, are modified as modifiers. azides, nitro and nitrosoamines, ammonium salts of carbonic acid and derivatives thereof, preferably azodiisobutyronitrile, azodioyklohexylcyanide, azodicarbonamide, diazoaminobenzene, 1,5-endomethylene-J, 7-dinitroso-1,3,5,7-tetraazacycloctane, 1,3> 5-trinitroso-1,3,5-triazacyclohexane, N, N'-dimethyl-Ν, Ν-dinitrosoterephthalamide, dinitroso-tetrahydroimidazo-4,5-d] imidazole-2,5- (1H, 3H) -diones, benzosulfohydrazide , aminoguanidine sulfate, terephthalazide, biphenyl-4,4'-disulfazide, azidoethanol nitrate, sym-tetraazidobenzoquinone, nitroguanidine, nitromo-urine, ammonium carbonate, ammonium carbamate, singly or in mixtures with each other, and / or thermodynamically unstable Mixtures of individually stable constituents, preferably an equimolar mixture of nitrite / calcium and calcium / ammonium 40 or birurea and urea, in an amount of 0.1 to 25.0% by weight, preferably in an amount of 1.2 to 20 0% by weight · weight of adhesive in its mixture ·