SI8712426A8 - Process for preparing of urea-cinnamonaldehyde resins - Google Patents

Description

CHEMICAL INSTITUTE »BORIS KIDRIC» p.o. Ljubljana

Process for the preparation of urea-cimetaldehyde resins

Technical field of the invention

C 08 J 3/08 c 08 L 61/24 c 08 K 5/00 c 09 D 3/52 c 09 D 3/66 c 08 Mr 12/12 c 08 Mr 14/08.

The present invention relates to the field of organic chemical technology, specifically to a process for the preparation of new urea-cimetaldehyde resins useful as binders, e.g. in laminates, presses, sealants and adhesives.

A technical problem

There was a need to prepare a new type of condensate, i.e. new urea-cimetaldehyde resins that would be useful in the form of low, medium or highly condensed products as binders, e.g. for laminates, presses and coatings, in a technologically advanced process, in organic medium, with high conversions.

The state of the art

DE-OS 27 57 176 describes urea-aldehyde resin-based varnishes prepared by condensation of urea or a derivative thereof with butyraldehyde or isobutyraldehyde in the presence of strong acid, and treatment with alkali alcohol in the aromatic hydrocarbon as solvent. The product obtained is a bright, alcohol-soluble resin, with a softening point at 146 ° C.

DE-OS 34 06 473 A1 describes aqueous dispersions for the manufacture of coatings containing urea and CH-acid aldehydes condensates, specifically isobutyraldehyde, further vinylpyrrolidone and vinylpropionate copolymer.

Description of solution to a technical problem with implementation examples

Now we have found that we get new quality condensates with the reaction of urea, which is four-functional and cymetaidehydride, which is a three-functional unsaturated aldehyde, so that not only its aldehyde group is involved in the reaction, as in the prior art, but also double bonds .

Thus, in the first phase of synthesis, a series of lower molecular oligomers with free aldehyde groups, double bonds, -NH ₂ , -NH-, -CHOH and dive groups are formed, which in the next phase react to larger molecules and finally to a three-dimensional, crosslinked, cured resin . Preferably, two reactions take place: the addition of the -NH ₂ urea group to the double bond and to the carboxyl group of cimetaldehyde. Depending on the ratio of urea to cimetaldehyde, mono, di, tri and tetrasubstituted urea are produced. The resulting resin is a mixture of a number of components, some of which have been identified by GPC and NMR. All of these components react either with each other or with the output monomers into higher molecular compounds and finally into a cured three-dimensional resin that is insoluble and non-flammable.

The course of the reaction of the invention is illustrated by the following reaction scheme

H ₂ N-CO-NH ₂ + (yCH = CH-CHO

H ₂ N-CO-NH-CH-CH = CH-O

OH

I

CHO NH

CO., LTD

h ₂ n-co-nh-ch-Q> - *

H-NH-CO

high molecular weight products, drones, ethers

The amount of oligomers formed and the direction of the reaction depend on the temperature, the urea-cimetaldehyde ratio, the amount and type of catalyst, and the reaction time. Lower ratios lead to the formation of mono and disubstituted urea, whereas they lead to higher ratios to the formation of three and tetrasubstituted urea, dives and ethers.

The process of the invention is carried out by condensing the urea and cimetaldehyde in a molar ratio of 1: 1 to 1: 2 in an organic solvent, in the presence of acid catalysts, at a temperature in the range of 60 to 130 ° C, preferably at reflux of the reaction medium, and then is cured at a temperature of 100 to 150 ° C with a crosslinker selected preferably from the amine group.

Dimethylsulfoxide or its mixtures with alcohols are preferably used as an organic solvent in the condensation of urea with cimetaldehyde.

For example, hydrochloric, formic or phosphoric acid is used as acid catalysts for condensation.

Preferably hexamethylenetetramine is used as the crosslinker from the amine group.

The most favorable polar ratio of urea to cinnamaldehyde is 1: 1 to 1: 2, because a higher or lower ratio leads to resins with poorer physical properties that do not harden.

The catalyst is used in conventional catalytic amounts, e.g. 0.01 to 0.02 moles per mole of urea. The amount of acid depends on the speed of the reaction.

At reaction time e.g. Between 2 and 6 hours, molecular weights between 700 and 1000 were obtained and the reactions proceeded to high conversion.

It is understood by those skilled in the art that the reaction rate can be increased by extended reaction times or by increasing the amount of catalyst.

The amount of oligomers formed and the direction of the reaction depend on the temperature, the urea-cimetaldehyde ratio, the amount and type of catalyst, and the reaction time. Lower ratios lead to the formation of mono and disubstituted urea, whereas they lead to higher ratios to the formation of three and tetrasubstituted urea, dives and ethers.

The curing of the resin can be achieved by a temperature between 100 and 150 ° C, preferably above 135 ° C, and by using amines as crosslinking agents. The solvent first evaporates and then the resin solidifies. Water is eliminated and methylene, ether, and submerged bridges are formed in the product. The product obtained is a reddish-brown color from which unreacted components can be extracted. The amount of extract depends on the reaction time and temperature and the addition of the hardener.

- 6 The product of the invention is a mixture of various components with the following composition:

1-Phenyl-1-urea-3-propanal-1 2 - 5%

1-Phenyl-3-hydroxy-3-ureido-2-propene 3-8%

1-Phenyl-1,3> 3-triureido-propane 10 - 20%

1-Phenyl-1,3-diureido-3-hydroxy-propane 10 - 20% (1-phenyl-3-hydroxy-1-ureido-3-ureylenepropane) _n 40 - 60% (1-phenyl-1,3- diureido-3-ureyl-propane) _n 20 - 40%

The proportion of individual components in the mixture depends on the condensation conditions of the resin. The average molecular weight depends on n, that is, the number of units in the macromolecule, with n in the range up to 10.

The product obtained is useful as a binder for various types of laminates, presses and heat-curing adhesives.

The present invention is illustrated by the following examples, but by no means limited thereto.

EXAMPLE 1

Resin in molar ratio urea: cimetaldehyde: HCl = 1: 1: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 19.2 g of cimetaldehyde and 0.18 g of concentrated hydrochloric acid were added. The mixture was heated in a reaction vessel with a magnetic stirrer to reflux at 100 ° C.

The reaction time was 4 hours. The resulting light red guest-viscous resin was soluble in tetrahydrofuran, methanol and ethanol and partially soluble in acetone. It had the following characteristics

Dry matter (135 ° C, 3 hours) (%) 71.0

Density (kg / m ³ ) 1,110

Unreacted urea (%) 11.3

Unreacted cinnamaldehyde (%) 0.5

Proportion of -NH groups (%) 14,8

Average molecular weight 730

Methanol extraction after curing at 135 ° C for 3 hours with 10% HMTA (%)

5.4

- 8 EXAMPLE 2

Resin in molar ratio urea: cimetaldehyde: HCl = 1: 1: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 19.2 g of cimetaldehyde and 0.18 g of concentrated hydrochloric acid were added. The mixture was heated in a reaction vessel with reflux and magnetic stirrer to reflux at 100 ° C. The reaction time was 6 hours. The resulting light red, viscous viscous was partially soluble in tetrahydrofuran and acetone and soluble in methanol and ethanol. The resin had the following properties:

Dry matter (135 ° C, 3 hours) (%) 72.6

Density (kg / m ³ ) 1200

Unreacted urea (%) 12.8

Unreacted cinnamaldehyde (%) 0.5

Proportion of -NH groups (%) 0.5

Average molecular weight 780

Extraction in methanol after curing at 135 ° C for 3 hours with 10% HMTA (%) 3.4 (HMTA = hexamethylenetetramine)

- 9 EXAMPLE 3

Resin in molar ratio urea: cimetaldehyde: HCl =

1: 1: 0.005

Material: Cimetaldehyde was distilled directly by reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 19.2 g of cimetaldehyde and 0.09 g of concentrated hydrochloric acid were added. The mixture was heated in a reaction vessel with a reflux condenser and a magnetic stirrer to reflux at 100 ° C.

The reaction time was 2 hours 40 minutes. The resulting light-brown, medium-viscous resin was partially soluble in tetrahydrofuran and acetone and soluble in methanol and ethanol. It's pitch

C had the following characteristics:

Dry matter (135 ° C, 3 hours) ' (%) 70.7 Density (kg / m ³ ) 1150 Unreacted urea (%) 14,0 Unreacted cinnamaldehyde (%) 4.3 Proportion of -NH groups (%) 25.6 Average molecular weight 630 Methanol extraction at 135 ° C with 10% HMTA (%) hardening 7.4

(HMTA = hexamethylenetetramine)

EXAMPLE 4

Resin in molar ratio urea: cimetaldehyde: HCl = 1: 2: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 38.2 g of cimetaldehyde and 0.18 g of concentrated hydrochloric acid were added. The mixture was heated in reflux to reflux at 90 ° C. The reaction time was 4 hours. The obtained, light-brown, brown highly viscous resin was well soluble in tetrahydrofuran, methanol, ethanol, and partially soluble in acetone. The resin had the following properties.

Dry matter (135 ° C, 3 hours) (%) 77.0

Density (kg / m ³ ) 1130

Unreacted urea (%) 1.4

Unreacted cinnamaldehyde (%) 4,8

Proportion of -NH groups (%) 7.8

Average molecular weight 760

Extraction in methanol after curing at 135 ° C for 3 hours with 10% HMTA (%) 2.1 (HMTA = hexamethylenetetramine)

EXAMPLE 5

Resin in molar ratio urea: acetaldehyde: HCOOH = 1: 2: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction, and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C. 12 g of urea were dissolved in 12 g of dimethylsulfoxide and 38.2 g of cimetaldehyde and 0.23 g of formic acid were added. The mixture was heated in reflux to reflux at 90 C. The reaction time was 4 hours. The resulting light brown, highly viscous resin was well soluble in methanol and ethanol, partially soluble in tetrahydrofuran and acetone. The resin had the following properties:

Dry matter (135 ° C, 3 hours) (%) 77.7

Density (kg / m ³ ) 1210

Unreacted urea (%) 3.2

Unreacted cinnamaldehyde (%) 5,0

Proportion of -NH groups (%) 4.0

Average molecular weight 810

Methanol extraction after curing at 135 ° C for 3 hours with 10% HMTA (%) 3.2 (HMTA = hexamethylenetetramine)

EXAMPLE 6

Resin in molar ratio urea: cimetaldehyde: H ^ PO ^ = 1: 2: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 38.2 g of cimetaldehyde and 0.65 g of concentrated phosphoric acid were added. The mixture was heated in a reaction vessel with reflux condenser and magnetic stirrer to reflux temperature at 90 ° C. The reaction time was 4 hours. The resulting light brown, highly viscous resin was well soluble in methanol and ethanol and partially soluble in tetrahydrofuran and acetone. The resin had the following properties:

Dry matter (135 ° C, 3 hours) (%) 77.6

Density (kg / m ³ ) 1170

Unreacted urea (%) 2.0

Unreacted cinnamaldehyde (%) 4,5

% NH groups (%) 4,5

Average molecular weight 850

Extraction in methanol after curing at 135 ° C for 3 h with 10% HMTA (%) 2,4 (HMTA = hexamethylenetetramine)

EXAMPLE 7

We took it as Example 6, except that the reaction was ongoing

The resin obtained had the following properties:

Dry matter (135 ° C, 3 hours) (%) 79.6

Density (kg / m ³ ) 1180

Unreacted urea (%) 0.9

Unreacted cinnamaldehyde (%) 1,1

Proportion of -NH groups (%) 4.0

Average molecular weight 870

Methanol extraction after curing at 135 ° C for 3 hours with 10% HMTA (%) 2.2 (HMTA = hexamethylenetetramine)

Use of resin for various purposes:

a) Use of compression mass: Dissolve the resin in a solvent and mix 40 to 50% solution with 10% hardener (eg HMTA).

Up to 60% of the filler (asbestos, wood flour, kaolin, chalk, cellulose fibers) is added to the solution and the mixture is thoroughly folded in a kneader. The mixture was dried at a temperature of up to 50 ° C in a vacuum oven to a volatile content of 3 to 6%. The mass is then compressed in a hydraulic press at elevated temperature and pressurized

b) Use of resins for technical laminates: Impregnate the paper, cloth, asbestos cloth or glass cloth with the resin and hardener solution. The fabric is then dried in a dryer and pressed in a hydraulic press at a temperature between 140 and 16 ° C into laminates.

c) Use of resin for fillers: Add hardener and filler such as chalk or kaolin to the resin and pour the individual parts with it. These portions are then heated to 14O-16O ° C until the resin has solidified. The layer thickness should not exceed 1 mm.

The best way to make economic use of the invention

Resin in molar ratio urea: cimetaldehyde: HCl = 1: 1: 0.01.

Material: Cimetaldehyde was distilled immediately before the reaction and urea was used with a biuret content below 2% and a melting point of 133 to 135 ° C.

g of urea was dissolved in 12 g of dimethylsulfoxide and 19.2 g of cimetaldehyde and 0.18 g of concentrated hydrochloric acid were added. The mixture was heated in a reaction vessel with a magnetic stirrer to reflux at 100 ° C.

The reaction time was 4 hours. The resulting light red guest-viscous resin was soluble in tetrahydrofuran, methanol and ethanol and partially soluble in acetone. It had the following characteristics:

Dry matter (135 ° C, 3 hours) (%) 71.0

Density (kg / m ³ ) 1,110

Unreacted urea (%) 11.3

Unreacted cinnamaldehyde (%) 0.5

Proportion of -NH groups (%) 14,8

Average molecular weight 730

Methanol extraction after curing at 135 ° C for 3 hours with 10% HMTA (%) 5.4

For

CHEMICAL INSTITUTE »BORIS KIDRIC» p.o. Ljubljana

20227-VI-89-MD

Claims (4)

PATENT APPLICATIONS 1. A process for the preparation of urea-cimetaldehyde resin, which is a mixture of composition 1-Phenyl-1-urea-3-propanal-1 2-5% 1-Phenyl-3-hydroxy-3-ureido-2-propene 1-Phenyl-1,3,3-triureido-propane 1-Phenyl-1,3-diureido-3-hydroxy-propane (1-phenyl-3-hydroxy-1-ureido-3-ureylenepropane) _n (1-phenyl-1,3-diureido-3-ureylene-propane) _n wherein n is 1 to 10. 3 - 8% 10 - 20% 10 - 20% 40 - 60% 20 to 40%, characterized in that the urea and cimetaldehyde are condensed in a 1: 1 to 1: 2 ratio, in an organic solvent, in the presence of acid catalysts, at a temperature of 60 to 130 ° C and then cured at a temperature of 100 to 150 ° C with a crosslinker from the amine group. _z Process according to claim 1, characterized in that dimethylsulfoxide or its mixture with alcohol is selected as an organic solvent Process according to claim 1, characterized in that hydrochloric, formic or phosphoric acid is selected as the catalyst. 4. The method of claim 1, wherein hexamethylenetetramine is selected as the crosslinker. For 2O227-VI-88 / LZ CHEMICAL INSTITUTE »BORIS KIDRIC» p.o. Ljubljana: SUMMARY We propose a process for the preparation of new urea-cimetaldehyde resins with composition 1-Phenyl-1-urea-3-prOpanal-1 2 - 5% 1-Phenyl-3-hydroxy-3-ureido-2-propene 3 - 8% 1-Phenyl-1,3,3-triureido-propane 1.0 - 20% 1-Phenyl-1,3-diureido-3-hydroxy-propane 10 - 20% (1-Phenyl-3-hydroxy-1-ureido-3-ureylenepropane) ^ (1 - n 10) 40 - 60% (1-Phenyl-1,3-diureido-3-ureylene-propane) _n 20 - 40%, by condensation of urea and cimetaldehyde in an acidic medium and an organic solvent and curing. The products are useful as binders in laminates, sealants and adhesives.