RU2489259C1 - Method of producing sealed tubes from glass-fiber material - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to a of fiber glass higher-strength pipes to be used in aircraft engineering, shih building, chemical and petrochemical industries. Film epoxy resin-based glue BK-36 is wound on the mandrel while fiber glass layers are formed bi combined processes of fiber glass impregnation with film glue and forming impregnated fiber glass of alternating layers of glass fabric and film glue at glue volume content oif said fabric making 45-50%. Note here that said process is performed at 0.085-0.095 MPa for 30-40 minutes at 65-70°C and, further, for 100-120 minutes at 170°C.

EFFECT: higher tube tightness, simplified process.

1 dwg, 1 tbl

Description

The invention relates to the manufacture of fiberglass pipes with increased tightness and can be used for the manufacture of piping for air conditioning systems of aircraft, in the chemical, petrochemical and other industries.

Known methods of manufacturing pipes by winding or laying previously impregnated with a binder glass or carbon fabric, bundles, fibers, followed by curing the binder in autoclaves or thermal furnaces, where the bag is formed ("dry method"), as well as the "wet method" when the reinforcing material is wetted with a binder directly before laying (more often when winding) on a mandrel (see Composite materials: Handbook / VV Vasiliev, VD Protasov, VV Bolotin et al .; edited by VV Vasiliev, Yu.M. Tarnopolsky. - M.: Mechanical Engineering, 1990. - 512 s; Calculation and rational design of curved pipes made of reinforced plastics: monograph / V.P. Bagmutov, V.N. Tyshkevich, V. B. Svetlichnaya, VPI (branch) of Volgograd State Technical University. - Volgograd, 2008. - 158 p.).

It is possible to provide high continuity and tightness of the material in these methods by evacuation at the impregnation stage, which is quite difficult technically. In addition, in both cases, production workers have to work with harmful substances - binders.

Known methods of manufacturing fiberglass pipes with a sealing inner layer of thermoplastic film, which consists in winding on the mandrel of a thermoplastic film, sintering it and subsequent molding on the basis of the fiberglass layer. As a sealing layer, use polyethylene, polypropylene, polyvinyl chloride films, films based on a copolymer of acrylonitrile butadiene styrene and others (see Mullinoson J. Application of fiberglass products in chemical industries. - M .: Chemistry, 1973, p. 85-88).

However, the known methods do not provide sufficient tightness of the pipes due to the weak connection of the facing material in the lap and with the fiberglass layer.

Closest to the proposed invention in terms of technical nature and the achieved effect is a method of manufacturing sealed fiberglass pipes, which consists in winding a thermoplastic film on a mandrel, treating it with a solvent with medium dissolving ability and forming layers of structural fiberglass on the basis of the initiated unsaturated polyester binder followed by curing and additional processing of overlap areas of thermoplastic film initiated by unsaturated polyester binder (see AS No. 854736 USSR, IPC V 2923/12 Method for the manufacture of sealed fiberglass pipes / N.G. Nesterov, 3.P. Yazon, A.L. Tarasova, V.M. Kozin. Published 08/15/1981, Bulletin No. 20).

This method allows to ensure the tightness of the connection of the thermoplastic film in the overlap, but a sufficient tightness of the pipes is not provided. In addition, due to the use of solvent, this method is characterized by the complexity of the technology and the deteriorated sanitary and hygienic working conditions.

The technical result is to increase the tightness of the pipes, simplifying the technology of their manufacture and improving working conditions.

The technical result is achieved by the fact that VK-36 film adhesive based on epoxy resin is used as a film, and the formation of fiberglass layers is carried out by combining the process of vacuum impregnation of fiberglass with film adhesive with the simultaneous formation of the resulting fiberglass from alternating layers of fiberglass and film adhesive, while ensuring volumetric the glue content in it is 45-50%; the process is carried out at a pressure of 0.085-0.095 MPa, for 30-40 minutes at a temperature of 65-70 ° C and then for 100-120 minutes at a temperature of 170 ° C.

The use of epoxy-based film glue as a binder allows us to simplify the process, reduce the production time of pipes and improve working conditions because it excludes the operation of winding the thermoplastic film on the mandrel, treating it with a solvent and treating the binder with overlapping. The proposed method does not use a liquid binder and solvent, which reduces the content of harmful volatile components in the workplace.

In technological recommendations, technical and patent literature there are no solutions for the use of film adhesives as a binder in reinforced materials. In the existing technological recommendations and reference literature, VK-36 film glue (TU 1-596-389-96) is used for gluing various materials, including polymer composite materials.

The combination of vacuum impregnation and molding processes reduces the manufacturing time of pipes; provides uniform glue impregnation of fiberglass layers, continuity and tightness of the material.

Pressure, temperature and time conditions in the proposed method:

pressure 0.085-0.095 MPa, holding for 30 minutes at a temperature of 65-70 ° C, are necessary for uniform impregnation of fiberglass layers with glue with a total layer thickness of not more than 5 mm; a pressure of 0.085-0.095 MPa, an exposure of 100-120 minutes at a temperature of 170 ° C, are necessary for the complete curing of the film adhesive, ensuring the continuity and tightness of the material.

The limitation of the volumetric content of glue in the material is 45-50% due to the fact that an increase in the volumetric content of glue as a binder leads to a decrease in the strength of fiberglass (the optimum content of fiberglass is considered to be the content of the binder within 30-35% (see Composite materials: Reference / B. V. Vasiliev, V.D. Protasov, V.V. Bolotin and others; under the general editorship of V.V. Vasiliev, Yu.M. Tarnopolsky - M .: Engineering, 1990, 512 p.)), And decrease volumetric content of adhesive as a binder below the recommended level reduces hermetically It is the material quality and the outer and inner surface of the product due to the discontinuity of the material, poor infiltration. Thus, the proposed method, as an object of study, according to the authors, meets the criterion of "significant differences".

The combination of the proposed components and modes for forming sealed fiberglass pipes allows to increase the tightness of the material, simplify the technology, provide the ability to manufacture parts of complex shape, improve the working conditions of production workers.

The proposed method is graphically illustrated in FIG. 1, where 1 is a metal mandrel, 2 is a release layer, 3 is VK-36 film adhesive, 4 is a reinforcing material (4 layers of fiberglass E1-100, GOST 19907-83), 5 is a fluoroplastic tape, 6 is a drainage layer, 7 - vacuum bag. Elements of positions 2, 5, 6, 7 are necessary to ensure a typical technological process.

The manufacturing process of thin-walled pipes of the proposed method consists of the following operations. A 60 mm wide fluoroplastic tape with an overlap of 5 mm is wound on a metal mandrel with an outer diameter of 60 mm, having a taper to ensure removal of the finished product. Then, a layer of VK-36 film adhesive tape is wound end-to-end with a thickness of δ = 0.2 mm and a width of 60 mm. 4 layers of fiberglass E1-100 are wound on the adhesive layer with a cloth, onto which then a layer of tape of film glue is wound (the direction of winding is opposite to the direction of the first layer of glue). The thickness of the layers should be no more than 5 mm. Next, the actions of a typical technological process are carried out: a fluoroplastic tape is wound on an adhesive layer and a drainage layer is laid, after which the formed fiberglass is placed in a vacuum bag and then in a thermal furnace.

The combined process of impregnation and molding is carried out at a pressure of 0.085-0.095 MPa, for 30-40 minutes at a temperature of 65-70 ° C and then for 100-120 minutes at a temperature of 170 ° C.

The leakproofness test of fiberglass pipes was carried out using the “aquarium” method (A. Chernyshov. “Installation and Testing Technology for On-Board Aircraft Systems”, Moscow: Mashinostroenie, 1977, p.198, 204) by immersing samples in a water bath, creating samples excess pressure with air and measuring the volume of bubble gas release on the surface of the samples.

The quantitative value of tightness at constant test pressure was evaluated according to the dependence

$${\text{G}}_{\text{GP}}=\frac{{\text{V}}_{\text{P}}}{{\text{S}}_{\text{P}}\text{t}}\left[{\text{l / cm}}^{\text{2}}\text{c}\right]\text{,}$$

where G _GP - the level of tightness;

V _P - the volume of air bubbles collected in the funnel;

S _P - the surface area of the pipe;

t is the test time.

The results obtained during the tests are presented in table. one.

The test results allow us to conclude that the inventive method for the manufacture of thin-walled fiberglass pipes provides high tightness of the pipe material by air up to 0.3 MPa.

Fiberglass pipes were tested with dimensions: length 500-700 mm, diameter 60 mm, made by winding the following structures:

Type 1: two-layer winding of fiberglass TS-10 GOST 18170-79 based on a polyester binder;

Type 2: additionally molded inner layer of thermoplastic film (prototype);

Type 3: samples made according to the method proposed in the application: 4 layers of fiberglass E1-100 and alternating layers of film adhesive VK-36.

Table 1

The test results of the pipes for tightness, l / cm ² s Type of pipe Test Pressure, MPa 0.02 0.17 0.30 Type 1 0,020 - - Type 2 - 0.570 · 10 ^-5 - Type 3 0 0 0

Thus, the proposed method for the manufacture of sealed fiberglass pipes allows to increase the tightness of the pipes, simplify the technology of their manufacture and improve working conditions.

Claims (1)

A method of manufacturing a sealed fiberglass pipe, including winding onto the mandrel of the film and forming layers of fiberglass to it, characterized in that the film is VK-36 based on epoxy resin, and the formation of fiberglass layers is carried out by combining the process of vacuum impregnation of fiberglass with film glue with the simultaneous formation of the obtained fiberglass from alternating layers of fiberglass and film glue, while providing a volumetric content of glue in it of 45-50%, while They exist at a pressure of 0.085-0.095 MPa, for 30-40 minutes at a temperature of 65-70 ° C and then for 100-120 minutes at a temperature of 170 ° C.

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