CS251519B1 - Laminated material on base of polypropylene reinforcement and method of its production - Google Patents

Abstract

The solution is in the field of laminated production materials for structural and electrical engineering woven or nonwoven applications reinforced with polypropylene fibers β imlpregnant binder reaciplastic resins. The laminate consists of an optional 1 a number of layers composed of woven, or nonwoven polypropylene fibers weighing 60 to 500 g. m “2 preimpregnated thermosetting resin such as e.g. phenolic resin, phenol, or cresolaniline formaldehyde, melamine formaldehyde, urea-formaldehyde, epoxy, or eipoxyphenolic in ipomer weight to polly propylene 1: : 0.3 to 1: 1.6. The manufacturing of the laminate is based on the fact that polypropylene reinforcement weighing 60 to 500 g. m “2 vo in the form of ticked or nonwoven fibers impregnated with bituminous reaplastid resin resin with a deposit of 30 to 160% % by weight of polypropylene reinforcement, further clad for the desired dried at 60 to 160 ° C and lysed at 20 to 180 minutes at 3 minutes up to 10 MPa and a temperature of 120 to 160 ° C.

Description

The present invention relates to laminated materials for structural and electrical applications with woven or non-woven reinforcement of polypropylene fibers or strips and with an impregnating binder based on thermosetting resins.

The purpose of the invention is to obtain a layered material with lower water absorption and better utility properties compared to layered materials (textiles of cellulosic textile materials) and to provide a technically and economically advantageous method for their production.

Up to now, cotton, viscose and mixtures thereof have been used as reinforcing components in the production of laminates in the electrical industry. Their task is to provide the required strength, electrical insulation properties, absorbency, specific gravity, impact resistance and the like.

The basic drawback of the prior art is that cellulose fibers are used for the technical product, which can be substantially more advantageously used in the textile industry for a range of clothing and home textiles.

Furthermore, the disadvantage of cellulosic fiber reinforcing materials is the very high water absorption, the associated possibility of microtbial corrosion and low insulation resistance. Both cotton and viscose, as hydrophilic materials, are imperfectly wetted with resin and, due to the presence of sorbed water, require higher temperatures during impregnation.

The above drawbacks are overcome in the invention describing a laminated polypropylene reinforcement material and a process for its manufacture according to the invention which consists of an optional number of layers composed of woven or non-woven polypropylene fibers having a basis weight of 60 to 500 g . m ~ ² impregnated with a thermosetting resin, e.g. phenolic, phenol-, or icresolaniline-formaldehyde, melamine-formaldehyde, urea-formaldehyde, epoxy, or epoxyphenolic resin, in a weight to polypropylene ratio of 1: 0.3 to 1: 1.6.

The process for the production of a laminate according to the invention is characterized in that the polypropylene reinforcement has a basis weight of 60 to 500 g. m ² in the form of woven or non-woven fibers is impregnated with a resin-based resin-resin solution, the deposit of which is 30 to 160% by weight on the weight of the polypropylene reinforcement, further dried at 60 to 160 ° C and pressed for 20 to 180 minutes at a pressure of 3 to 10 MPa and a temperature of 120 to 160 ° C.

An advantage of the solution according to the invention is that the POP fiber is characterized by its pronounced hydrophobic character resulting from the absence of any polar functional groups. Heavy reinforcing materials have low critical surface energy and are more wetted with a hydrophobic resin.

Furthermore, it is a matter of fact that the polypropylene sheets are practically free of water, which is a substantial advantage over the uniformity of the applied resin compared to cotton alcohol hydrophilic fiber. It is possible to reduce the deposition temperature of the resin and the molding, which has a large impact on the energy ibilance of the process.

Polypropylene, as a solid dielectric, has a povrch higher surface resistance, and its value varies little with relative humidity, unlike cotton, which substantially improves the dielectric properties of the layered materials.

Another advantage of the polypropylene used as reinforcing material is its lower specific weight and thus the lower specific weight of the laminate obtained.

In order to obtain higher mechanical strengths, it is preferable to use polypropylene fabrics having a basis weight of 60 to 500 g. . m ² . For the impregnation of the polypropylene reinforcement, various thermosetting plastics binders, e.g. phenolic, phenol, or Iresolaniline-formaldehyde, meilaminofoirmaldehyde, urea-formaldehyde, epoxy, polyester and others. Also preferred is the use of an epoxy binder modified with the aforementioned types of resins, in particular phenolic.

In the following, the polypropylene reinforcement laminate is described in the examples.

Example 1

Polypropylene fabric weighing 160 g. m- ² is impregnated with phenol-cresoil with a formaldehyde resin at a resin loading of 120%. The impregnated material was laminated to a thickness of 4 mm after pressing, dried at 130 ° C and 60 psi for 60 minutes. The properties of the obtained layered material are given in Tab. First

Table 1

Properties of layered material based on phenol cresol formaldehyde resin with polypropylene ‘fabric as reinforcement

Specific gravity (kg. M ~ ³ ) 1 057

Water absorption at 4 mm (mg) thickness

Insulation resistance after 24 hours

water storage (Ohm) 1.9 X TO ¹⁰

Bending strength (MPa) 90

Cold shearability up to rake 1.5 mm, grade 0.4

Loss factor 'tg δ:

at 50 Hz 0.05

Permittivity ε at 50 Hz 3.5

Example 1 and d 2

Polypropylene fabric with a basis weight of 340 g. m- ² is impregnated with an epoxycresol binder so that the resin deposit is 120% by weight of the polypropylene fabric and, after drying at 130 ° C, is pressed in the presence of a release film at 140 degrees C and 7 MPa for 120 minutes.

Example 3

Fabric based on polypropylene] ^- staple fibers with a basis weight of 170 g. m- ² is first washed in a detergent solution to remove the fabric softener. After drying, it is impregnated with an acetone solution of an epoxy resin with an amine dye (e.g. diamino-diphenylmethane, dicyandiamide) so as to deposit a dried bituminous binder, and was 100%, i.e. a final basis weight of 340 g. m ' ² . The fabric dried at 135 ° C, topped up in the number of sheets required for the desired laminate depth, is pressed at 135 ° C and 7 MPa for 180 min. The layered insulator thus prepared is characterized by excellent electrical insulation properties and low absorbency, as can be seen from Tab. Second

Table 2

Properties of the epoxy resin based laminate with polypropylene fabric reinforcement

Specific gravity (kg, mr ³ ) 1 017

Humidity at 5 mm (mg) thickness 15

Insulation resistance after 24 hours

water storage (Ohm)> 1.10 ¹⁵

Loss factor tg ó:

at 1 MHz 0.015 at 700 MHz 0.017

Permittivity ε:

at 1 MHz 2.7 at 700 MHz 2.7

Breakdown Strength in Layers at 90 ° C in Oil (kV) 60 Electrical Strength Perpendicular to Layers at 90 ° C in Oil

Claims (2)

SUBJECT A laminated material based on polypronylene reinforcement, characterized in that it consists of layers composed of woven or non-woven polypropylene fibers with a mass of from 60 to 500 g. m ^-2 pre-impregnated with a thermosetting resin, e.g. phenolic resin, phenol-, or cresolaniline-photrmaldehyde, melamine-formaldehyde, urea-formaldehyde, epoxy, or epoxyphenolic, in weight to polypropylene reinforcement ratio 1: : 0.3 to 1: 1.6. 2. A process according to claim 1, characterized in that the polypropylene reinforcement has a basis weight of 60 to 500 g. . m ^-2 in the form of woven or non-woven fibers is impregnated with a resin solution of a thermosetting resin having a deposit of 30 to 160% by weight of the weight of the polypropylene reinforcement, adjusted to the desired depth, dried at 60 to 160 degrees C and pressed for 20 up to 180 minutes at a pressure of 3 to 10 MPa and a temperature of 120 to 160 degrees C.