CS238995B1 - A method for producing phenolic pressing and injection molding materials - Google Patents

Abstract

The invention relates to a method for producing phenolic and injection materials in one operation in a suspended state under intensive mixing in the temperature range of 60 to 170 °C from primary raw materials or semi-products. Short production times and productive physical and mechanical properties are achieved - bending strength higher than 80 MPa, dimensional stability according to Martens higher than 145 oC. Impact strength higher than 0.7 J/cm. The semi-products floated in the above-mentioned way contain less than 0.5% by mass of free phenols.

Description

MAREK OLDŘICH, Eng.,

ΜΑΪΑΤΚ0 JAN ing., PARDUBICE ,

MAREK PETR ing., ČELÁKOVICE,

HAJIČEK 0D0N ing.,

PRIMLOVÁ BLANKA ing., PARDUBICE, TATÍČEK JAROSLAV, SVÍTKOV

Method of producing phenolic molding and injection materials

The invention relates to a method of producing phenolic and injection molding compounds in one operation in a suspension under intensive mixing in the temperature range of 60 to 170 °C from primary raw materials or semi-products. Short production times and productive physical and mechanical properties achieved - bending strength higher than 80 MPa, shape stability according to Martens higher than 145 ^o C. _? impact toughness higher than 0.7 J/cm .

The semi-products floated in the above-mentioned manner contain less than 0.5% by mass of free phenols.

?38 995 (51) Int Cl?

C08G8/00

- 4,238,995

The invention relates to a method for producing phenolic plastics suitable for processing by pressing, extrusion, injection molding as well as semi-finished products intended for further processing processes. Phenolic plastics according to the invention are produced in one production facility in one or more consecutive production operations.

Phenolic plastics are thermosetting thermosets, mass-produced for processing into various technical and consumer products. The known processes for producing these thermosets work in several separate, independent production operations; differing in technological process and production equipment with large space requirements. In the first operation, approximately 50% phenol-formaldehyde resin is prepared in an acidic or alkaline environment at temperatures below 100°C. Due to the exothermic process, the condensation process is very lengthy (on the order of several hours) in order to prevent an explosive uncontrolled condensation process. After reaching the required condensation degree and stabilizing the semi-product, excess water is removed by separation or evacuation, free phenol is removed by steaming, etc. The anhydrous resin - the semi-product - must be rapidly cooled, for example, in a flaking device; into the form of solid particles, granules, which are intended for the next operation. In the second essential operation, this solid resin is mixed with organic or inorganic fillers, lubricants, catalysts, colorants, and even lubricants in a homogenizing device. The homogenized mixture is melted, kneaded, further homogenized and converted into its final chemical form - a processable thermoset resin - in batches on steam-heated twin rollers, where the effects of temperature, friction, and pressure create a continuous form of plastic, which is crushed into its final form after cooling.

238 99S

-2crushed or granulated. This entire process can be carried out by continuous (Raschig) or batch kneading. The most modern and progressive methods perform this homogenizing kneading operation, during which the fillers are simultaneously impregnated with molten resin in robust continuous screw extruders of the Buss or Sttiddle type, which are followed by a unit for granulation, crushing and cooling of the resulting product. All these methods require high machinery, construction and space costs.

Organic and inorganic fillers for these "dry" technologies must be pre-surfaced and stabilized to achieve good physical-mechanical and electrical properties.

The mentioned shortcomings are eliminated by the method of producing phenolic molding and injection materials and semi-products by polycondensation from primary raw materials, i.e. phenols, aldehydes, organic and/or inorganic fillers, lubricants and catalysts, the essence of which is that polycondensation takes place in a single operation in a suspension with intensive mixing in the temperature range from 60°C to 170°C.

Semi-finished products based on novolaks and/or resoles can be used as primary raw materials.

The preparation of phenol-formaldehyde resin by condensation of phenols and formaldehyde in the presence of organic and/or inorganic fillers, including other additional components, enables rapid condensation under any temperature conditions due to the large surface area of the fillers, which significantly shortens the condensation time without causing an explosive polycondensation process.

Precise control of the polycondensation process allows the use of even the strongest catalysts in the maximum amount possible economically and in terms of reaction kinetics.

- 3,238,995

Since the condensation starts from monomeric reaction raw materials, it is ideal for impregnation of all fillers and additional components, thereby achieving highly homogeneous products with excellent physical-mechanical and electrical properties.

This fluid system from raw materials allows for any initial condensation temperature, depending on the degree of preheating of the raw materials, before the addition of formalin and catalysts.

During the production process, the material is in fluid suspension in the form of small particles or granules, which are dried after the condensation operation is completed, preferably under reduced pressure, and are capable of being processed using any processing technology.

A large-capacity production unit _f · due to the simplicity of the technology and the simplicity of the production equipment/ • requires significantly lower investment machinery and construction costs.

The intermediate preparations according to the invention have zero or minimal free phenol content, so that for further use, e.g. when used for epoxy/novolac resins, their further treatment is not required.

Example 1

The following is added to the reactor heated to 160°C:

wood flour 23.0 kg stearin 1.0 kg phenol 28.0 kg p-toluenesulfonic acid 1> kg ^Fe 2°3 0.5 kg mounting wax 1.0 kg After 2 minutes of intensive mixing will be released formalin (36.5%) 24.0 kg

after which condensation takes place under reflux at a temperature of 110°C for 15 min. The resulting novolac semi-product contains 5% free phenol in the resin.

After the condensation is complete, the suspension is dosed;

238,995

triethanolamine 2.0 kg formalin (36.5%) 5.0 kg hexamethylenetetramine 5.0 kg MgO 0.2 kg CaO 1.0 kg CaCO ₇ 10.0 kg

After 2 min of intensive stirring under reflux, the product

dried under vacuum of 0.01 MPa for 5 min* into a final product in the form of uniform fine granules, suitable for final processing. The resulting product has a bulk density of 65 «fr/l, a bending strength of 85 MPa, an impact strength of 0.7 J/eia^ and a Martens dimensional stability of 140°C.

Example 2

The following is added to the reactor with intensive stirring, the walls of which are heated to 120°C:

Cellulose fiber 30.0 kg waste wood flour 40.0 kg stearin 2.0 kg montan wax 1.0 kg phenol 56.0 kg formalin (36.5%) 49.0 kg

HC1 (36.5%) 1.4 kg fibrous asbestos 90.0 kg

Condensation of the filled novolak takes place within 8 minutes, with a free phenol content of 1% in the resin. Triethanolamine 10.0 kg formalin 15.0 kg ammonia (25%) 15.0 kg hexamethylenetetramine 8.0 kg are released into the system.

CeCO ₃ 10.0¾

After 6 min. of intensive stirring under reflux at a temperature of 120°C, the resulting product in the form of a fine powder is dried under a vacuum of 0.02 MPa for 4 min. The resulting material has a weight of 850 g/l, a bending strength of 95 MPa, an impact strength of 0.87 J/cm^ and a dimensional stability according to Martens of 155°C.

-5,238,995

Example 3

The following are added to the reactor heated to 140°C:

40.0kg 25.0kg 30.0kg

1.5kg 2.0kg

1.5kg 1.0kg

1.5 kg phenol cellulose ground beech mica magnesium stearate MgO ozokerite carbon black KOH

While constantly stirring with high-speed mixers at a rotational speed of 25 m/s, the raw materials are heated for 4 minutes, after which 45.0 kg of formalin (36.5%) is introduced into the stirred system.

The condensation mixture is kept at a temperature of 120°C for 15 min. under reflux, after which the reaction mixture is dried under a vacuum of 0.03 MPa for 8 min. and discharged in the form of granules or flakes for cooling and transferred to final processing. The bulk density of the plastic* is 850 g/l, bending strength 80 MPa, dimensional stability according to Martens 145°C, specific surface electrical resistance 10 ³ ^(? ₀

Example 4

The following is added to the intensively stirred thermoset:

beech wood flour 20.0 kg micro-ground asbestos 20.0 kg stearin 1.5 kg phenol 15.0 kg technical cresol 15.0 kg oxalic acid 2.0 kg formalin (36.5%) 22.0 kg

The reaction mixture is heated within a few minutes with stirring at a rotational speed of the main stirring system of 30 m/s to 160°C and within 25 minutes the condensation of the filled novolak is completed. The temperature of the reaction mixture is reduced to 100°C. To stabilize the novolak, the following is added:

triethanolamine 2.0 kg

CaCO^ - 5.0 kg

-6,238,985

Immediately after stabilization, the novolak is dried under vacuum of 0^.005 MPa for 10 min. The free phenol content in the resin is lower than 0.5%, the dropping point is equal to 89.5°C, the degradation temperature

197°Go

Example 5

The following is added to the reactor heated to 150°C with intensive stirring:

beech wood flour 40.0 kg fibrous asbestos 10.0 kg magnesium stearate 1.5 kg magnesium oxide 2.0 kg assembly wax 1.5 kg phenol formaldehyde resole (50%) 100.0 kg

The temperature of the duplicate reactor is maintained at 150-160°C, the main mixing system is maintained at a mixer rotational speed of 20 m/s. After 3 minutes of interaction, the product is dried within 5 minutes into the form of fine granules with a bulk density of

800 g/l, bending strength 90 MPa, impact strength 0.95 J/cm and dimensional stability according to Martens 160°C.

Example 6

The following is added to the reactor heated to 60°C while stirring:

phenol 60.0 kg hydrochloric acid, 36.5% 1.5 kg formalin (36.5%) * 45.0 kg stearin 1.5 kg

During 40 min. with constant stirring at a rotational speed of 30 m/s, polycondensation takes place, after which 4.0 kg of triethanolamine is added.

Within 5 minutes _, the novolak is stabilized, dried for 10 minutes under a vacuum of 0.07 MPa and the novolak is discharged in the form of a powder with a free phenol content of 0.3%, a pouring point of 85 °C and a degradation temperature of 188 °C _.

Claims (2)

SUBJECT OF THE INVENTION 238 995 1 / Method for producing phenolic molding and injection weight by polycondensation of primary raw materials, i.e. _the phenols, aldehydes, organic and / or inorganic fillers, lubricants, and catalysts / wherein polykondenzaee takes place in one operation, in suspension with vigorous stirring in a temperature range 60 <> C to 170 ° C _o 2. Process according to claim 1, characterized in that novel raw materials based on novolaks or resols _e can be used as primary raw materials.