CS241414B1 - Method of pressing aminoplastics production - Google Patents

Abstract

Process for producing pressing aminoplasts wherein the solid polycondensation raw materials, such as melamine, urea, 6-caprolactam, cellulose and calcium carbonate with mixing in the same or introduced the apparatus above the condensation temperature from up to 180 ° C, then liquid raw materials are metered in ie formalin and catalytic system and the reaction mixture is kept fluid the suspension at 60 to 160 ° C, then performs drying of the granulated polycondensate at temperatures up to 160 ° C. In the procedure a constant polycondensation kinetics is achieved throughout the process. Originated aminoplasts are processable by all available technologies rheological properties (shear stress 0.05 to 0.20 MPa). Preparation of aminoplasts narrow distribution curve and constant network density.

Description

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Process for producing press aminoplasts

A process for the production of molded aminoplasts wherein solid polycondensation raw materials such as melamine, urea, 6-caprolactam, cellulose and calcium carbonate are heated with stirring in the same or above equipment above a condensation temperature of from 70 to 180 ° C, then liquid feed materials are metered. i.e., formalin and catalyst system and the reaction mixture is maintained in fluidized bed at a temperature of 60 to 160 ° C, followed by drying the granular polycondensate at a temperature of up to 160 ° C. The process achieves constant polycondensation kinetics throughout the process. The resulting aminoplasts are workable by all available technologies and exhibit improved rheological properties (shear stress of 0.05 to 0.20 MPa). Preparation of aminoplasts with narrow distribution curve and constant mesh density.

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The present invention relates to a process for the manufacture of molded aminoplasts, namely modified melamine-formaldehyde, melamine, urea and urea-melamine, which are suitable for injection molding, extrusion and compression processing, characterized by high flowability and aging resistance.

Aminoplastics are thermosetting thermosetting plastics that are applied to demanding moldings especially for electrical engineering and mechanical engineering.

Previously known condensation processes for the preparation of these thermosetts work at the beginning of the condensation so that the temperature of the reaction mixture rises slowly under the influence of the heated reactor until it reaches the same temperature as that of the reactor. From this point on, the condensation is continued under isothermal conditions until the desired condensation degree is reached. The disadvantage of this process is the relatively long condensation process and the changing condensation temperature and the condensation velocity due to this. degree of branching, resulting in a polydisperse structure of the cured plastic. This inherently produces thermosetting plastics with variable and mostly non-optimal properties of rheological, electrical and physical-mechanical.

Technological method of production of aminoplasts in fluidized bed according to MS. No. 126,796 and 129,445 provide a shear stress of the plastics in the range of 0.25 to 0.40 MPa. Progressive method of production of modified melamine-formaldehyde compounds according to the art.

No. 212,873, provides aminoplasts having a shear stress of 0.15 to 0.25 MPa.

These disadvantages are overcome by a process for bending off-white amine plastics from solid polycondensation solids such as melamine, urea, 6-caprolactam, cellulose, calcium carbonate and formalin, which is the object of the present invention, which consists in solid solid polycondensation raw material. and the fillers are heated with stirring above a condensation temperature of from 70 ° C to 180 ° C, after which they are dosed with formellin and catalytic eystem and the reaction mixture is maintained in fluidized bed at a temperature of 60 ° C to 160 ° C, whereupon The granular polycondensate is dried at a temperature of up to 160 ° C.

According to the invention, it has been found that the condensation process follows the same reaction kinetics throughout the condensation process. This results in a completely homogeneous polymeric macrostructure structure in the resulting plastic ensuring maximum quality parameters of all desired properties. * The benefit of controlling constant polycondensation conditions throughout its duration is that the temperature of the condensation system from the beginning to the flow is a high value, which will ensure the solid raw material, thereby creating The maximum value of the reaction enthalpy, which determines all the important properties of the aminoplasts produced * The process according to the invention allows, even in the subsequent drying period of granular aminoplasts in fluidized bed, that the walls of the fluidized bed reactor can They can be maintained at 160 ° C or higher, i.e., up to the curing temperature of the aminoplasts, thereby making it possible. It achieves the shortest production time of the whole cycle. A significant benefit of this process is that despite high condensation and drying temperatures no sticking is formed on the reactor walls. Another benefit is that aminoplasts of high flowability are obtained. Thus, for example, the modified aminoplasts of this process achieve lower shear stresses than phenoplasts and polyesters and approach values of 0.02 to 0.04 MPa (at 120 [deg.] C.) that otherwise exhibit only epoxy molding compositions.

- 3 Example 1 241 414

Raw materials are dosed into the heated reactor:

Aspen cellulose < 30, - kg Melamine 55, - 6-caprolactam 30, - Calcium carbonate 70, - Calcium stearate 2, - Titanium white 5, -

The raw materials are heated to 150 ° C with vigorous stirring. When this temperature is reached, liquid raw materials are introduced into them:

Formalin 36,5% wt · 80, - kg

Triethanolamine 5, -

Orthophosphoric acid 5 »-”

The polycondensation of all reactants is carried out in a fluidized bed at a system temperature of 115 ° C for 3 min, after which the granular material is dried at a reactor wall temperature of 16 ° C and under a vacuum of 15 klk. within 3 minutes · The resulting product is characterized by an impact strength of 1.2 J / cra, a bending strength of 100 MPa, an enthalpy of curing exotherm of 200 J / g, a viscosity of 3 · 10 ^ Ρ s at an injection pressure of 150 MPa and a temperature of 120 ° C. shear stress 0.02 MPa at 120 ° C ·

Example 2

The following raw materials are heated to 130 ° C in a pre-mixer:

Melamine 60, - kg

Cellulose 50, - ”

Zinc stearate 1 '-

Litopon 5, —- ”

Calcium carbonate 5 »-”

After heating, they are metered into a vigorously stirred reactor heated to 100 ° C, while impregnating the following liquid components:

Formalin 36.5 wt. Triethanolamine Formic acid

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100, - kg 2, -

0.05

The condensation of the whole system takes place from the first moment of contact of the reactants at 100 ° C for 8 min. The uniform granulated material is dried at a reactor temperature of 100 ° 0 under a vacuum of 70 kP * for 8 min. The resulting product is characterized by a flexural strength of 120 MPa, an impact strength of 15 µm / µm, an enthalpy of curing exotherm of 150 J / g, a zero content of low molecular weight polycondensation products, and a shear stress of 0.15 MPa at 120 ° C.

Example 3

The following solid feedstocks are introduced into the heated and vigorously stirred reactor:

Urea 60, - kg

Cellulose 50, - ”

Stearin 2, -

Phthalocyamin green 2, - * K

The raw materials are heated to 115 ° C and a solution containing:

Formalin 36.5% game. 120, - kg

Hexamethylenetetramine ⁴ 9, -

Phthalic anhydride 2, - ”

The polycondensation of the reactants takes place in a fluidized bed reactor at 90 ° C for 10 min. The finely granulated mass is dried at a reactor temperature of 120 ° C, a vacuum of 60 kPa for 5 min. The resulting product is characterized by an impact strength of 1.6 J / cm, a bending strength of 120 MPa, an enthalpy of curing exotherm of 250 J / g, a shear stress of 0.2 MPa at 120 ° C.

- 5 Example 4

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Raw materials are metered into the heated reactor

Melamine 30, - kg

Urea 30, - ”

Cellulose 45, - ”

Stearin 1.50

Titanium White 3, - ”

Ftalooyan Blue 0.40 ”

6-caprolactam 2.- »

The raw materials are heated to 135 ° C with vigorous stirring, and after reaching this temperature, liquid reaction raw materials are introduced into them:

Formalin 36.5% wt * 90, - kg

Orthophosphoric acid 3, -

The polycondensation of the components of the system is carried out in a fluidized bed at 110 ° C for 6 min., Then the granular material is dried at a reactor temperature of 150 ° C and under a vacuum of 70 kPa for 5 minutes. The resulting product is characterized by an impact strength of 1.0 J / m. flexural strength 120 MPa, enthalpy of cure exo term 180 J / g, shear stress 0,10 MPa at 120®C ·

Claims (1)

SUBJECT OF THE INVENTION 241 414 Process for the production of formalin molding aminoplasts and solid polycondensation raw materials and fillers such as melamine, urea, δ-cappolactam, cellulose and calcium carbonate, characterized in that the solid polycondensation raw materials and fillers are heated with stirring above a condensation temperature of 70 ° C to 180 ° C then, after reaching this temperature, formalin and the catalyst system are metered in and the reaction mixture is maintained in fluidized bed at a temperature of 60 ° C to 160 ° C. then the granular polycondensate is dried at a temperature of up to 160 ° C.