CS224439B1 - Process for the production of modified melamine-formaldehyde mass - Google Patents

Abstract

The invention relates to a method for producing a modified melamine-formaldehyde material and/or resin, particularly suitable for injection molding and as a binder for laminated materials. Melamine-formaldehyde modified plastics belong to the category of thermosetting materials and meet the demanding requirements for the production of technically complex moldings. Materials of this type must exhibit good processability in a wide range of processing conditions, when they transition to a cured state under the influence of temperature and pressure. Modified aminoplastics polyamides (GDR patent 125 315, 126 412, Japanese patent 54 112 993, 54 126 296) require a relatively long condensation time, moreover, according to the above patents, the modified resin is first prepared, with which the filler is only impregnated in the next stage. The above disadvantages are largely eliminated by the method of production of melanin-formaldehyde mass according to the invention, in which the polycondensation is carried out by a process in the simultaneous presence of a catalyst, melamine, formaldehyde and fillers and/or by a process in the simultaneous presence of a catalyst, formaldehyde and cellulose, whereby melamine and other fillers are dosed during the polycondensation. The essence of the invention lies in the fact that the condensation is carried out in the presence of hexamethylenediamine salt of dicarboxylic acid of formula HOOC—(CH2)n—COOH, where n = 0 to 11 in an amount of 1 to 100% by weight of the weight of melamine at a temperature of 75 to 95 °C in one operation with stirring. The modifying effect of the method of production according to the invention significantly increases the elasticity of the material, improves the rheological and physical-mechanical properties and allows the use of the content of mineral fillers in an amount of 0 to 65% of the total weight of the thermosetting plastic. Examples of implementation: 1. The following components are introduced into reactors at a temperature of 90 °C with intensive stirring: Melamine 100 g Hexamethyldiamine salt of pimelic acid 50 g Technical formalin 36% 140 g Aspen cellulose 70 g Sodium tetraborate 0.2 g Verzál yellow G 1 g 224439 The polycondensation takes place within 25 minutes and the product is then dried under vacuum at 0.08 MPa in the form of granules. After grinding into powder, the product is

Description

The invention relates to a method for producing a modified melamine formaldehyde compound and/or resin, particularly suitable for injection molding and as a binder for laminated materials.

Melamine-formaldehyde modified plastics belong to the category of thermosetting materials and meet the demanding requirements for the production of technically complex moldings. Materials of this type must exhibit good processability over a wide range of processing conditions, where they undergo a cured state under the influence of temperature and pressure.

Modified aminoplast polyamides (GDR patent 125 315, 126 412, Japanese patent

112,993, 54,126,296) require a relatively long time for condensation poles, moreover, according to the mentioned patents, a modified resin is first prepared, with which the filler is only impregnated in the next stage.

The above disadvantages are largely eliminated by the method of producing melaninoformaldehyde mass according to the invention, in which the polycondensation is carried out by a process in the simultaneous presence of a catalyst, melamine, formaldehyde and fillers and/or by a process in the simultaneous presence of a catalyst, formaldehyde and cellulose, with melamine and other fillers being dosed during the polycondensation. The essence of the invention lies in the fact that the condensation is carried out in the presence of a hexamethylenediamine salt of a dicarboxylic acid of the formula HOOC—(CH ₂ ) _n —COOH, where n = 0 to 11 in an amount of 1 to 100% by weight of the weight of melamine at a temperature of 75 to 95 ° C in one operation with stirring.

The modifying effect of the production method according to the present invention substantially increases the elasticity of the material, improves the rheological and physical-mechanical properties and allows the use of mineral fillers in an amount of 0 to 65% of the total weight of the thermoset.

Examples of implementation:

1. Into reactors at a temperature of 90 °C, under intensive

the following ingredients will be added to the mixture: Melamine 100g Hexamethyldiamine salt pimelic acid 50g Technical formalin 36% 140g Aspen cellulose 70g Sodium tetraborate 0.2g Capital Yellow G 1g

The polycondensation takes place within 25 minutes and the product is then dried under vacuum at 0.08 MPa in the form of granules. After grinding into powder, the product is usable for further processing, and is characterized by a viscosity of 4.59 X 10 ³ Pa . s at an injection pressure of .150 MPa and a temperature of 120 °C, an impact strength of 0.81 J/cm ² , a bending strength of 105 MPa and an activation energy of the curing reaction of 0.2946 kJ/mol.

2. The following polycondensation components are introduced into an intensively stirred reactor at a temperature of 85 °C:

Melamine 100 g

Oxalic acid hexamethylenediamine salt 100 g

Formalin technical 36% 210 g

Beech cellulose 50 g

Calcium carbonate 120 g

Potassium hydroxide 0.5 g

Zinc stearate 4 g

Capsular Red A3B 2 g

The polycondensation reaction takes place within 25 minutes, after which the product in the form of granules is dried under a vacuum of less than 0.1 MPa. The resulting material is characterized by a viscosity of 3.78 x 10 ³ Pa . s at an injection pressure of 150 MPa and a temperature of 120 °C, an impact strength of 0.72 J/cm ² , a flexural strength of 109 MPa and an activation energy of the curing reaction of 0.2971 kJ/mol.

3. The following components are added to the reactor at a temperature of 80 °C with gentle stirring:

Melamine 100 g

Hexamethylenediamine salt

Claims (1)

SUBJECT Process for producing a modified melamine-formaldehyde composition by a process in the presence of catalyst, melamine, formaldehyde and optional fillers and / or a process in the presence of catalyst, formaldehyde and cellulose, wherein melamine and other fillers are metered during malonic acid 70 g Formalin 36% 170 g Triethanolamine 3 g After polycondensation within 30 minutes, the prepared resin is used for impregnation. The resin is characterized by a viscosity of 1.12 x 10 ³ Pa. with a temperature of 120 ° C and a curing reaction activation energy of 0.2963 kJ / mol. 4. The following components are charged to the reactors with vigorous stirring at 90-95 ° C: Hexamethylenediamine brasylic acid salt 40 g Formalin 36% 170 g Sodium hydroxide 0.5 g Spruce cellulose 60 g After 15 minutes, additional starting components were introduced into the reactors: Melamine 100 g Litopon 80 g Sodium tetraborate 0.5 g Titanium white 4 g A modified aminoplast is formed over a further 15 minutes, which is then dried in the form of granules under a vacuum of 0.07 MPa. The resulting material is characterized by a viscosity of 5.54 X 10 ³ Pa. with an injection pressure of 150 MPa and a temperature of 120 ° C, an impact strength of 0.79 J / cm ² , a flexural strength of 97 MPa and a curing reaction activation energy of 0.3006 kJ / mol. < Process according to claim 1, characterized in that the condensation is carried out in the presence of a hexamethylenediamine salt of the dicarboxylic acid of the formula HOOC - (CH ₂ ) n - COOH, where n = 0 to 11 in an amount of 1 to 100% by weight. 75 to 95 ° C in one operation with stirring.