RU2012502C1 - Method of processing of thermosetting plastics - Google Patents

Abstract

FIELD: plastics. SUBSTANCE: processing of thermosetting plastics includes plasticizing moulding material and its subsequent moulding in a mould. Used as a base moulding material is a mix of moulding and casting glass-reinforced plastics in mass relation (90-50): (10-50) and moulding of the plasticized mix in a mould is accomplished at a pressure of 5 to 25 MPa. EFFECT: facilitated procedure. 2 tbl

Description

 The invention relates to the processing of thermosets, namely fiberglass based on thermosetting resins, and can be used in the manufacture of press and injection products in the automotive, electrical and other industries.

 A known method of processing thermosets (1), including direct pressing of the material and curing it in the mold. The disadvantages of this method are the high pressing pressures of 30-55 PMa and the long exposure time of the product in the mold, which leads to high processing costs.

 Closest to the proposed technical essence is a processing method using screw plasticization before pressing (2), which allows to reduce the pressure to 25-35 MPa and the pressing cycle by pre-heating the press material and lowering its viscosity. However, plasticization of press materials requires high energy costs (torque on the screw reaches 50-60 kgm) and causes increased wear of the cylinder-screw pair. In addition, with this method of processing thermosetting there are difficulties in pressing products of complex configuration (for example, collectors) associated with the insufficiently low viscosity of the plasticized press material.

 The aim of the invention is to expand technological capabilities by expanding the range of products obtained, including a complex configuration (for example, collectors, brush holders, electric motor armature package) and cost reduction during their production by reducing the technological cycle or using cheaper raw materials.

 This goal is achieved by the fact that according to the proposed processing method, which includes plasticizing the press material and subsequent molding and curing it in the mold, a mixture of pressed and molded fiberglass based on thermosetting resins in a mass ratio (90-50) is used as a press material : (10-50), respectively, and the molding of the plasticized mixture in the mold is carried out under a pressure of 5-25 MPa, changing in the indicated intervals with a change in the ratio of components in the mixture in proportion to the linear order Well. Mixtures of pressed and molded fiberglass in a mass ratio of (90-50): (10-50) have a lower viscosity compared to pressed fiberglass, which allows plasticizing the material at lower torques, reduces wear on tooling and equipment, requires lower pressing pressures, since there is a linear relationship between the pressing pressure and the viscosity of the press material (3).

 Reducing the pressing pressure makes it possible to increase the nesting rigging or use a press of a smaller tonnage. In addition, a decrease in effective viscosity allows molding products of complex configuration, for example, collectors, brush holders, a package of electric motor anchors, and thus it becomes possible to expand the assortment of press and injection products.

 The final technical results that can be obtained by carrying out the invention are to increase productivity, reduce energy costs and metal consumption of equipment, which generally leads to lower costs for the manufacture of products from thermosetting plastics.

 Information confirming the possibility of carrying out the invention are given in the examples of its implementation and table. 1-3.

 PRI me R 1. Press material: a mixture of pressed fiberglass GSP-8 (TU 6-11-263-77) and injection molded fiberglass AG 4Gr (TU 6-07-294-89) based on phenol-formaldehyde resin and glass fibers . The content of AG - 4Gy is 10-50%.

The pressed product is a standard bar 10x15x120 mm. The pre-prepared mixture was plasticized and dosed in a screw plasticizer dispenser. Dose kneaded at a temperature of 80-100 ^{° C} was molded in a mold at 160-170 ^{° C} with a pressure of 5-25 MPa. At the same time, measurements were made of the pressing pressure and the torque developed by the plasticizer screw for different contents of the mixture components. The effective viscosity was determined (by the method of rotational viscometry) for each batch of the mixture. The results of technological tests for a mixture of materials GSP-8 and AG - 4Gy are given in table. 1.

 PRI me R 2. Press material: a mixture of pressed fiberglass GSP-400 and injection-molded fiberglass AG-4Gr with a content of the latter 10-50%.

 The mixture was processed into model products according to the technological scheme shown in example 1 with the same processing modes. The results of technological tests for a mixture of materials GSP-400 and AG - 4Gy are given in table. 2.

 PRI me R 3. Press material: a mixture of extruded fiberglass GSP-32 (TU 6-11-263-77) and injection molding epoxy-plastic UP-7-200 L2 (TU 6-05-241-339-82) on epoxy resin and chopped fiberglass. The content of injection glass fiber is 10-50%.

A standard sample - a 4x10x80 mm bar was obtained by transfer casting in a press. The pre-prepared mixture was loaded into the injection cylinder of the mold, where the dose was plasticized as it passed through the sprue channels and samples were then formed. The molding temperature is 190 ^° C. In this case, the required transfer casting force was measured and the pressing pressure of the samples was determined for different contents of the mixture components. The effective viscosity was determined for each batch of the mixture. The results of technological tests for a mixture of materials GSP-32 and UP-7-200L2 are given in table. 3.

From the table. 1-3 it is seen that a decrease in the effective viscosity due to the use of injection-molded fiberglass in the mixture leads to a change in the torque during plasticization and allows to reduce the pressing pressure during molding of products, while the pressing pressure decreases with an increase in the content of injection-molded fiberglass proportionally according to the linear law:
P = a - kS, where P is the compaction pressure, MPa;
a is a coefficient depending on the starting components in the mixture (for example 1 a = 27 MPa, for example 2 a = 29.5 MPa, for example 3 a = 29.5 MPa).

 k is a constant coefficient for the selected mixtures (for a mixture of AG - 4Gy k ≠ 0.44; for a mixture containing UP - 7 - 200L2 k = 0.44).

 S is the percentage of injection component.

 PRI me R 4. The press material is a mixture of pressed fiberglass GSP-32 and injection molded fiberglass AG - 4Gy with a mass ratio of 50: 50%.

This mixture was subjected to technological testing for the possibility of processing on injection molding machine by injection molding. Dose previously prepared was charged into a hopper of the injection machine, kneaded at a dose of 80-100 ^{° C} and standard samples were molded at 160 ° ^C showed normal mastication process and molding process. The implementation of the invention on the injection molding machine is one of the options for expanding technological capabilities through the use of a mixture.

Claims (1)

 METHOD OF REHABILITY PROCESSING, including plasticization of the press material and subsequent molding and curing of it in the mold, characterized in that, in order to expand technological capabilities and reduce processing costs, a mixture of thermosetting pressed and molded fiberglass is used as the press material resins in a mass ratio of 90 - 50: 10 - 50, respectively, and the molding of the plasticized mixture in the mold is carried out under a pressure of 5 - 25 MPa, which varies at the indicated intervals with the ratio of components in the mixture is proportional to the linear law.

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