RU2470047C2 - Binder for prepregs and method of producing said binder - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of polymer materials meant for producing prepregs. The binder contains epoxy triphenol resin - triglycidyl ether 1,1,3-tri(oxyphenyl)propane, epoxy-diane resin, thermoplastic polyester with molecular weight of 30000 and a hardener. The hardener is a product of reacting diglycidyl ether of diethylene glycol and a boron trifluoride complex with benzyl amine in ratio of (2.5:1). The method involves the following steps: obtaining a product of reacting diglycidyl ether of diethylene glycol and a boron trifluoride complex with benzyl amine by gradually adding the complex to the resin heated to (50-55)°C in ratio of (1:2.5) for 1 hour; mixing for 1 hour; adding the obtained product to a prepared melt of epoxy resins in a mixture with polyester.

EFFECT: invention enables to avoid use of solvents and increases heat-resistance and impact viscosity of composite materials in the articles.

2 cl, 2 tbl, 3 ex

Description

Technical field

The invention relates to the field of production of polymeric materials intended for the manufacture of prepregs, which are widely used in industry, in particular aerospace.

State of the art

A binder for prepregs is known, including an epoxytriphenol resin - triglycidyl ether 1,1,3-tri (hydroxyphenyl) propane, a low molecular weight epoxidian resin, a hardener - dicyandiamide and bis (N, N'-dimethylcarbamide) diphenylmethane, as well as a solvent - an aliphatic acetone.

A binder is obtained by mixing the components at a temperature of (58-62) ° C for 2.5 hours (patent SU 1677961, IPC B29C 4/20, publ. 04/10/1996).

Fiberglass or other fibrous fillers are impregnated with a binder.

However, the presence of a residual solvent in the prepreg causes pore formation during the molding process, which reduces the water resistance and strength characteristics of composite materials.

The closest known solution is a binder for prepregs, including an epoxytriphenol resin - triglycidyl ether 1,1,3-tri (oxyphenyl) propane, a low molecular weight epoxy resin, a high molecular weight epoxy resin, hardeners - dicyandiamide and bis (N, N'-dimethylmethyl) and, if necessary, solvents, a mixture of aliphatic alcohol and acetone.

A binder is obtained by mixing the components, first hardeners are mixed, crushed to a finely dispersed state and introduced into a low molecular weight epoxy resin (1: 3), after which the resulting mixture is ground and combined with a previously prepared melt of epoxy resins using a solvent if necessary (patent RU 2176255 , IPC C08L 63/00, С08К 13/00, publ. 11/27/2001).

This binder allows to obtain products with good water resistance, however, insufficiently high heat resistance and increased fragility do not allow using it, for example, in the manufacture of interior panels with complex spatial shapes.

SUMMARY OF THE INVENTION

An object of the invention is the development of a binder that eliminates the use of solvents and increase the heat resistance and toughness of composite materials in products.

This object of the invention is solved in that the binder for the prepregs, including the epoxytriphenol resin - triglycidyl ether 1,1,3-tri (oxyphenyl) propane, epoxidian resin and hardener, contains as a hardener the product of the interaction of diethylene glycol diglycidyl ether and boron trifluoride complex with benzylamine ratio (2.5: 1) and additionally a thermoplastic complex polyester with a molecular weight of ~ 30,000, with the following ratio of components in parts by weight:

epoxytriphenol resin 70-75 epoxy resin 14-16 polyester 2.5-3.5 hardener 8.5-9.5

The technical problem is also solved by the method of producing a binder, which consists in mixing these components, and first, the product of the interaction of diglycidyl ether of diethylene glycol and a complex of boron trifluoride with benzylamine is obtained by gradually introducing the complex into a resin heated to (50-55) ° C in the ratio (1: 2 5) for 1 hour and subsequent stirring for 1 hour, then the resulting product is introduced into a pre-prepared melt of epoxy resins in a mixture with polyester.

According to the invention, an ETF epoxy resin is used (TU 2225-316-09201208-94), an ED-10 epoxy resin (GOST 10578-84 Amendment No. 1), diethylene glycol diglycidyl ether (DEG-1 aliphatic epoxy resin) (TU 2225-527- 00203521-98), TF-82 polyester (TU 6-05-1654-84) and a complex of boron trifluoride with benzylamine UP-605/3 (TU 6-10-125-91).

The invention is illustrated by the following examples.

Example.

First, the product of the interaction of diethylene glycol diglycidyl ether and a complex of boron trifluoride with benzylamine (hardener) is obtained. Diethylene glycol diglycidyl ether (DEG-1) is loaded into the reactor, the stirrer is turned on, and the contents of the reactor are heated to (50 ± 5) ° C. Then, a complex of boron trifluoride with benzylamine (UP-605/3) is added uniformly in portions through the loading hatch to the reactor. The ratio of DEG-1 and UP-605/3 is (2.5: 1). The contents of the reactor are stirred for 1 hour at the indicated temperature. The resulting product is cooled with stirring to room temperature and poured into a dry clean container. The product of the interaction of DEG-1 and UP-605/3 (hardener) is a yellow viscous transparent liquid. Mass fraction of epoxy groups - not less than 23%.

ETF brand epoxy 15–20 hours before preparation of the binder is cooled in a refrigerator at (7 ± 2) ° С. The cooled resin is mechanically crushed into pieces no larger than 20 mm before being loaded into the mixer.

Samples of ETF and ED-10 resins are loaded into the mixer. The contents of the mixer are heated to 120 ° C and stirred for 1 hour until a homogeneous melt is obtained. Then, a portion of TF-82 polyester resin, a linear complex polyester, which is a copolymer based on dimethyl terephthalate and diethylene glycol, is added uniformly in portions over 1 hour. The contents of the reactor are stirred at 120 ° C for 1 hour.

The finished product is cooled with stirring to (70 ± 5) ° C. Then, the hardener obtained earlier is introduced through the loading hatch. The contents of the mixer are stirred for 0.5 hours, after which a binder sample is taken for analysis.

According to the described technology were prepared samples of binders, the composition and properties of which are shown in tables 1 and 2 in comparison with the known.

Table 1 No. Name of components, parts by weight Examples one 2 3 one ETF epoxytriphenol resin 70 73 75 2 Epoxydian resin ED-10 fourteen fifteen 16 3 Polyester TF-82 2.5 3.0 3,5 four Hardener 8.5 9.0 9.5

table 2 Properties of cured binders one 2 3 Famous Glass transition temperature Tg ° C (tg of mechanical loss angle) 170 176 182 178 Impact strength, kJ / m ² 16 22 19 fourteen Elongation ε,% 4.8 5.2 5,4 3.4

The obtained binders were used for the manufacture of unidirectional carbon prepregs in a horizontal impregnation unit UOL-300.

The technological properties of carbon prepregs make it possible to obtain blanks by winding, manual and mechanized laying out. Subsequent polymerization can be carried out by press, autoclave and thermal vacuum methods.

The binder content in the prepreg ranges from 36 to 43%, the volatile content from 0 to 0.3%.

Due to the introduction of a binder complex polyester (resin TF-82) and optimization of the ratio of other components, while maintaining the glass transition temperature of ~ 175 ° achieved in the known composition, the impact strength and elongation of the cured polymer of the compositions are significantly increased by more than 30% by the examples table 1.

An increase in the toughness of the polymer matrix without deterioration of its technological characteristics and heat resistance was achieved by modification with the linear thermoplastic polyester - TF-82. The introduction of high molecular weight (MM ~ 30000) polyester into the reaction mass at a precondensation temperature of 140-150 ° C is not accompanied by its chemical interaction with the components of the melt and leads to the formation of a homogeneous oligomer-polymer system - a true solution of polyester in a block copolymer. In the process of heat treatment of the obtained oligomer-polymer system at a temperature of 160-170 ° C, along with the main curing reaction of the block copolymer, the so-called the reaction of "implementation" - the interaction of the epoxy cycles of the block copolymer with ester bonds of the polyester.

The “insertion” reaction proceeds at an insignificant rate, and ultimately the cured polymer matrix is a network block copolymer in which linear high-polymer macromolecules are immobilized with the formation of a clatratized snake-in-cell structure.

The increased elongations and impact toughness of the polymer improve the performance of the composite based on it under conditions of alternating temperatures, for example in space.

Thanks to the preliminary preparation of the reaction product DET-1 and UP-605/3, the effect of obtaining a homogeneous melt binder for producing prepregs without the presence of solvents is achieved, which increases the environmental safety of the process, reduces the energy consumption and cost of production of prepregs, in comparison with similar ones based on binders containing a complex of boron trifluoride with benzylamine dissolved in an inert solvent, for example, a solution binder of the ENPB brand [PI 1.2.168-81 (VIAM), Prepared the bonding of ENFB, the impregnation of carbon tape and the pressing of carbon fiber KMU-4L; TR 1.4.1057 (NIAT) Production of KMU-4L prepreg on the UPST-300 unit].

Claims (2)

1. A binder for prepregs, including an epoxytriphenol resin - 1,1,3-tri (oxyphenyl) propane triglycidyl ether, a low molecular weight epoxydian resin and a hardener, characterized in that it contains a product of the interaction of diethylene glycol diglycidyl ether and boron trifluoride complex with boron trifluoride a ratio of 2.5: 1 and additionally a thermoplastic complex polyester with a molecular weight of ~ 30,000 in the following ratio of components, parts by weight:
epoxytriphenol resin 70-75 epoxy resin 14-16 polyester 2.5-3.5 hardener 8.5-9.5 2. A method of producing a binder for prepregs, comprising mixing the components according to claim 1, characterized in that the product of the interaction of diethylene glycol diglycidyl ether and a complex of boron trifluoride with benzylamine is first obtained by gradually introducing the complex into a resin heated to 50-55 ° C in a ratio of 1: 2.5 for 1 h and subsequent stirring for 1 h, then the resulting product is introduced into the previously prepared melt of epoxy resins in a mixture with polyester.