RU2547744C1 - Binder, method for production thereof and binder-based composite material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: binder is produced from furfurol, urotropin, phenol-formaldehyde novolac resin, with the following ratio of components, pts.wt: Furfurol 95-105, urotropin 10-20, phenol-formaldehyde novolac resin 75-90. The group of inventions also relates to a method of producing said binder, which comprises steps of preparing a chemical composition from urotropin and furfurol, adding phenol-formaldehyde novolac resin to said composition and mixing the obtained mixture. The group of inventions also relates to a composite material made using said binder.

EFFECT: obtaining binder having physical and chemical properties which enable use thereof to produce industrial articles, including reinforced composite materials by pressure impregnation followed by moulding in a confining mould, obtaining binder using a simple technique with reduced loss of furfurol and minimal release thereof into the environment, obtaining composite material made using said binder.

12 cl, 4 tbl, 11 ex

Description

The group of inventions relates to binders (such as phenolic-furan binders) used for the manufacture of products for general industrial use, including composite materials, methods for producing such binders, as well as to composite materials based on them.

A known method of producing a binder obtained by the interaction by heating phenol, aldehyde, furyl alcohol in the presence of a catalyst (curing agent for the resin), followed by vacuum drying (US Patent No. 4,255,554, publ. 03/10/1981). The disadvantage of this method is that it requires the use of a vacuum drying step that complicates the technology, and that the binder obtained using it has a highly specialized application in foundry.

A known method of producing a phenol-furan binder by reacting phenol alcohol, furfural in the presence of a catalyst (curing agent for the resin) and a stabilizer when heated, in which the phenol alcohol is first condensed in the presence of a catalyst to achieve the desired viscosity, the resin is isolated, diethylene glycol is introduced and vacuum drying is carried out, then furfural is introduced and the condensation process is continued at a temperature of 50-80 ° C for 40-80 minutes at a given mass ratio of the starting components (Patent RF №2072366, publ. 01/27/1997). The disadvantage of this method is the complexity of the technological process of its implementation, as well as the fact that the binder obtained with its help can be used only in a narrow range of operating parameters (operating temperature, viscosity, etc.) and, accordingly, can be predominantly highly specialized application - for the manufacture of grinding tools on a rigid and flexible basis.

A known method of producing a binder (impregnating solution), which is furfuralphenol-alcohol resin, in which the resin is obtained by condensation of furfural with phenols in the presence of maleic anhydride, and urotropine is used as a curing agent in dissolved form (USSR Author Certificate No. 248195, publ. 10.12. ) The disadvantage of this method is the increased loss of furfural during condensation and the low environmental friendliness of the process due to the presence of furfural in the free state.

The technical problem solved by the claimed invention is to develop a binder composition with a wide range of applications, an economical and environmentally friendly way to obtain it, as well as a composite material based on it.

The technical result of the invention is to obtain a binder having such physicochemical properties that can be used for the manufacture of industrial products, including reinforced composite materials using pressure impregnation technologies, followed by molding in a restrictive form. For example, by impregnating a reinforcing filler in a continuous way on an impregnating machine, followed by pressing (autoclave, vacuum, hydro-melt methods, etc.). The technical result of the invention consists, moreover, in the development of a method for producing a binder using a simplified technology with a decrease in the losses of furfural and minimizing its release into the environment, as well as in the production of composite material made using this binder.

To achieve a technical result, a binder is prepared, obtained from furfural, urotropin, phenol-formaldehyde novolac resin in the following ratio of components in parts by weight:

Furfural 95-105 Urotropin 10-20 Phenol-formaldehyde novolac resin 75-90

As a component of the binder can be additionally used diazobisisobutyronitrile at its content, parts by weight: 0.1-2.

To achieve a technical result, a method for producing the above binder has been developed, comprising the steps of:

a) form a chemical composition of urotropine and furfural

b) phenol-formaldehyde novolac resin is introduced into said composition and the resulting mixture is stirred.

The chemical composition can be formed by introducing urotropine into liquid furfural and then mixing them at least until the dissolution of urotropin. Mixing the mixture obtained after the introduction of phenol-formaldehyde novolac resin can be carried out at least until a homogeneous mixture is obtained and its viscosity is stabilized.

In the method, the stabilization of the viscosity value of the mixture can be determined by the condition of maintaining the viscosity of the mixture in the range of 150-350 seconds for at least 10 minutes from the first measurement of viscosity.

As components of the binder, you can use urotropine and phenol-formaldehyde novolac resin in fragmented form. The components may be a plurality of resin particles not exceeding 15 mm in size and urotropin particles not exceeding 20 mm in size. In the method, before the completion of the mixing process, diazobisisobutyronitrile can be added to the mixture at its content in parts by mass: 0.1-2, and the temperature of the composition and mixture is maintained above 30 ° C.

To achieve a technical result, a composite material is developed made using the above binder.

The main features of the chemical processes of the developed method are as follows. The process of interaction of the starting components is carried out in two stages: the combination of furfural with a curing agent (polycondensation catalyst) urotropine, the combination of furfural-urotropine with phenol-formaldehyde novolac resin.

When heating and mixing furfural and urotropine, urotropine decomposes to form dimethylene amine and trimethylene amine bridges:

which then decompose with the release of ammonia and other nitrogen-containing compounds.

Between the novolac resin molecules and urotropin, methylene bridges —CH ₂ - and heat-resistant bonds of the type —CH = N — CH ₂ - are formed. An increase in molecules during condensation leads to an increase in the viscosity of the binder. The condensation process continues until a viscosity of 150-350 seconds is reached.

The additional introduction of diazobisisobutyronitrile into the composition of the binder stabilizer (parts by weight: 0.1-2) allows to slow down the curing process of the binder in the product and thereby ensure the highest quality of its manufacture (almost complete absence of pores, no signs of any delamination) for sufficient thick panels with a thickness of more than 15 mm. Increased porosity reduces the tightness of the product, increases moisture absorption. The high solubility of diazobisisobutyronitrile in furfural leads to the fact that within 10-20 minutes, diazobisisobutyronitrile is evenly distributed in the volume of the manufactured binder, reduces the internal stress in the polymer matrix, slows down the curing of the binder and thereby contributes to the exit of gas bubbles from the volume of the material with the corresponding elimination of even sufficiently small pores in the material.

The main features of the developed method for producing a binder are as follows. In a dry, clean reactor equipped with a stirrer and a jacket for heating or cooling, furfural is charged. Turn on the heating and into the reactor with the stirrer running, injected previously crushed urotropin. The loading of urotropin is carried out in small portions, which eliminates the formation of lumps. The dissolution time of the components is not more than 3 hours.

As a result of the interaction of furfural with urotropin, urotropine dissolves. At the end of the dissolution process, without shutting down the reactor and mixer, the calculated amount of crushed phenol-formaldehyde novolac resin is loaded into the reactor. During the mixing of the heated mixture, condensation occurs between furfural and phenol-formaldehyde resin in the presence of urotropine decomposition products. Low temperature, high-quality and prolonged mixing provides a "smoothly" flowing, gradual condensation. The temperature of the composition and mixture is 30-45 ° C.

Temperature equalization is achieved by the cooled liquid, which is fed into the jacket of the reactor. As a result of the condensation process, the viscosity of the binder increases.

After 10-11 hours of mixing, the phenol-formaldehyde resin dissolves and the first sample is taken to determine the viscosity of the mixture. The process can be considered complete when the viscosity of the mixture is stabilized, if two samples taken with an interval of at least 10 minutes meet the requirement: viscosity (conditional) 150-350 sec.

The resulting binder is a brown oily liquid without clots, impurities, which is well combined with other polar organic solvents. Good combination with solvents increases the ability to process the binder into products in various ways, both by applying a binder to the reinforcing filler, and by the method of molding the product.

It is known that furfural in a free state acts on the human body as a nerve poison. In the developed method, at all its stages of implementation, due to the peculiarities of the ongoing processes, furfural exists mainly in a bound, relatively safe form (as a part of mixtures and solutions), and almost all is used to obtain a binder. All the main processes for obtaining a binder are held in a closed container.

Based on the obtained binder, it is possible to manufacture, in particular, such composite materials as carbon fiber reinforced plastics, fiberglass plastic, foam heat-protective materials.

Examples of carrying out the invention

The invention is illustrated by the following examples of specific performance, in which phenol-formaldehyde novolac resin is used as the starting ingredients (for example, SF-010 according to GOST 18694); pure furfural reactive or technical furfural in accordance with GOST 10930; urotropin according to GOST 10437; diazobisisobutyronitrile according to TU 113.03-365-82.

Example No. 1

Before the manufacture of the binder, the initial components were prepared. Urotropin was crushed into pieces and sieved through a sieve with a mesh size of about 20 × 20 mm. The SF-010 resin was crushed and sieved through a sieve with a mesh size of about 15 × 15 mm. In a dry, clean, jacketed reactor for heating and cooling, 100 mass parts of furfural were loaded, heating and a mixer were turned on. During continuous operation, the stirrers were loaded in small portions of 10 parts by weight of urotropine. Simultaneously with stirring, the mass was heated to a temperature of 40 ° C. After 2.5 hours of heating and stirring, without shutting down the reactor and mixer, the phenol-formaldehyde resin SF-010 was loaded in small portions in an amount of 75 parts by mass. During the loading of the resin, the temperature of the solution in the reactor decreased to 30 ° C, at this temperature stirring was carried out for 10.0 hours. The viscosity of the obtained binder was measured using a viscometer type VZ-246 (diameter of the nozzle of the viscometer 4 mm), the viscosity of the first sample of the binder was in a predetermined range, the viscosity of the second sample was 160 seconds.

Based on the obtained binder, a composite material was made - a panel, with dimensions: length 220 mm, width 200 mm, thickness 8 mm. The technological process of its manufacture included the following steps:

- Preparation of a package of reinforcing filler;

- Preparation of the form and loading the filler package into the form;

- Connection of the form to the installation for impregnation under pressure;

- Impregnation of the package and control of the impregnation process;

- Curing the workpiece;

- Pressing and quality control of the material.

Silica fiberglass KT-11 according to TU 5953-158-05786904 was used as a filler. Cut glass fiber blanks were collected in a bag. The prepared bag was loaded into the mold. The mold was closed, connected to the impregnation unit, and the bag was impregnated. When a binder appeared in the trap, the impregnation time was fixed, which was 21 minutes. Then the mold was disconnected from the installation and the impregnated preform was cured and the mold was pressed out. Further, the material was removed from the mold and its quality was checked in appearance for the absence of blisters, delaminations, and non-impregnated areas. Swellings and delaminations, impregnated areas in the product were absent.

Example No. 2

A binder and composite material based on it were made analogously to example No. 1 with the following content of the components of the binder, parts by weight: furfural - 95, urotropin - 14, phenol-formaldehyde resin - 80. Mixing time of furfural and urotropin 3.0 hours, mixing temperature 40 ° FROM. The stirring time for dissolving the phenol-formaldehyde resin in the furfural-urotropin composition is 10.0 hours, the stirring temperature is 35 ° C. The viscosity of the second binder sample was 240 sec. The impregnation time of the package 23 minutes Quality control of the composite material showed that the molding surface is smooth, without binder sagging, creases, unimpregnated areas, delaminations and bloating.

Example No. 3

A binder and a composite material based on it were made analogously to example No. 1 with the following content of the components of the binder, parts by weight: furfural - 105, urotropin - 20, phenol-formaldehyde resin - 90. Mixing time of furfural and urotropin 2.5 hours, mixing temperature 40 ° FROM. The mixing time for dissolving the phenol-formaldehyde resin in the furfural-urotropin composition is 10.5 hours, the mixing temperature is 30 ° C. The viscosity of the second binder sample was 320 sec. The impregnation time of the package 28 minutes Quality control of the composite material showed that the molding surface is smooth, without binder sagging, wrinkles, unimpregnated areas, delaminations, and swellings.

Example No. 4

A binder and a composite material based on it were made analogously to example No. 1 with the following content of the components of the binder, parts by weight: furfural - 100, urotropin - 15, phenol-formaldehyde resin - 85. The mixing time of furfural and urotropin is 3 hours, the mixing temperature is 45 ° C. The time of dissolution and mixing of phenol-formaldehyde resin in the furfural-urotropin composition is 11 hours, the stirring temperature is 35 ° C. The viscosity of the second binder sample was 250 sec. The impregnation time of the package 25 minutes The quality control of the composite material showed that the molding surface is smooth, without binder sagging, bloating, delamination, creases, unimpregnated areas.

Example No. 5

A binder and composite material based on it were made analogously to example No. 1 with the following content of the components of the binder, parts by weight: furfural - 93, urotropin - 15, phenol-formaldehyde resin - 74. Mixing time of furfural and urotropin 2.5 hours, mixing temperature 45 ° FROM. The time of dissolution and mixing of phenol-formaldehyde resin in the furfural-urotropin composition is 10 hours, the stirring temperature is 35 ° C. The viscosity of the second binder sample was 180 sec. The impregnation time of the package 25 minutes Checking the quality of the composite material showed that there were no impregnated areas, but the quality of the molded panel was unsatisfactory - there were swelling and delamination.

Example No. 6

A binder and composite material based on it were made analogously to example No. 1 with the following content of the components of the binder, parts by weight: furfural - 120, urotropin - 8, phenol-formaldehyde resin - 75. Mixing time of furfural and urotropin 3.0 hours, mixing temperature 40 ° FROM. The time of dissolution and mixing of phenol-formaldehyde resin in the furfural-urotropin composition is 10.5 hours, the mixing temperature is 30 ° C. The viscosity of the first binder sample was 120 seconds, the viscosity of the second binder sample was 130 seconds. The impregnation time of the package 21 minutes Checking the quality of the composite material showed that it is unsatisfactory - there are delamination and swelling in the panel.

Example No. 7

A binder and a composite material based on it were made analogously to example No. 1, with the following content of the components of the binder, parts by weight: furfural - 100, urotropin - 25, phenol-formaldehyde resin - 110. Mixing time of furfural and urotropin 2.5 hours, mixing temperature 40 ° C. The time of dissolution and mixing of phenol-formaldehyde resin in the furfural-urotropin composition is 10.5 hours, the stirring temperature is 35 ° C. The viscosity of the second binder sample was 380 sec. Quality control of the composite material showed that due to the high viscosity during impregnation of the bag, a shift of the bag with the formation of folds and undersaturation of the bag is observed.

Example No. 8

A binder and composite material based on it were made analogously to example No. 1 with the difference that the panel thickness was chosen equal to 25 mm In the manufacture of the binder, an addition was made: 15 minutes before the end of the process of its preparation (without stopping the mixer in the reactor), a stabilizer was added to its composition in the following ratio of components, parts by weight: binder - 100, diazobisisobutyronitrile - 0.1. The viscosity of the second binder sample according to the proposed composition and technology was 225 seconds. The impregnation time of the package 32 minutes Quality control of the composite material showed that the molding surface is smooth, without wrinkles, unimpaired sections, delaminations, swellings, with a stable macrostructure in thickness.

Example No. 9

A binder and a composite material based on it were made analogously to example 8 with the following ratio of components, parts by weight: binder - 100, diazobisisobutyronitrile - 1.7. The mixing time of the binder and diazobisisobutyronitrile is 20 minutes. The viscosity of the second binder sample was 233 sec. The impregnation time of the package 35 minutes The quality control of the composite material showed that the molding surface is smooth, the macrostructure is stable in thickness, there are no impregnated areas, wrinkles, blisters and delaminations.

Example No. 10

A binder and composite material based on it were made analogously to example 8 with the following ratio of components, parts by weight: binder - 100, diazobisisobutyronitrile - 0.5. The mixing time of the binder and diazobisisobutyronitrile is 10 minutes. The viscosity of the second binder sample was 220 sec. The impregnation time of the package is 33 minutes. Quality control of the composite material showed that the molding surface is smooth, there are no impregnated areas, wrinkles, delaminations and blisters, the macrostructure is stable in thickness.

Example No. 11

A binder and composite material based on it were made analogously to example No. 8 with the following ratio of components, parts by weight: binder - 100, diazobisisobutyronitrile - 2.5. The mixing time of the binder and diazobisisobutyronitrile is 20 minutes. The impregnation time of the package is 34 minutes The viscosity of the second binder sample was 225 sec. Quality control of the composite material showed that increased porosity appeared in the molded sample, but there were no delamination and blistering.

The following table.1-4 systematize and supplement the information set forth in examples No. 1-11.

Tab. one The content of components and modes of manufacturing prototypes of the binder Component Content and Modes Examples of carrying out the invention one 2 3 four 5 6 7 Furfural, mass parts one hundred 95 105 one hundred 93 120 one hundred Urotropin, mass parts 10 fourteen twenty fifteen fifteen 8 25 Phenol-formaldehyde resin SF-010, parts by weight 75 80 90 85 74 75 110 Mixing time of furfural and urotropin, hour 2,5 3.0 2,5 3.0 2,5 3.0 2,5 Mixing temperature of the composition, ° C 40 40 40 45 45 40 40 The mixing time of phenol-formaldehyde and resin and composition of furfural and urotropine, hours 10.0 10.0 10.5 11.0 10.0 10.5 10.5 Mixing temperature, ° C thirty 35 thirty 35 35 thirty 35

Table 2 Characteristics of a binder and composite material based on it Characteristics Examples of carrying out the invention one 2 3 four 5 6 7 Viscosity according to VZ-246 (nozzle ⌀4 mm), sec 160 240 320 250 180 130 380 The impregnation time of the package, min 21 23 28 25 25 21 The package is not completely saturated Material quality No wet areas, no swellings or delaminations There are swellings, bundles The panel is not saturated Table 3 The content of the components of the prototype binder and the mixing time of the components Component content and mixing time Examples of carrying out the invention 8 9 10 eleven Binder, parts by weight one hundred one hundred one hundred one hundred Diazobisisobutyronitrile, parts by weight 0.1 1.7 0.5 2,5 Mixing time min fifteen twenty 10 twenty Table 4 Characteristics of a binder and composite material based on it Characteristics Examples of carrying out the invention 8 9 10 eleven Viscosity according to VZ-246 (nozzle ⌀4 mm), sec 225 233 220 225 Impregnation time, min 32 35 33 34 Product quality No cracks, delaminations, blisters, macrostructure homogeneous in thickness Increased porosity

As can be seen from the above data, the properties of the binder depend on the ratio of its initial components and the conditions of the process.

The binders obtained in examples 5, 6, 7 and 11 did not ensure the manufacture of high-quality products, which indicates the inappropriateness of using the ratios of the components for the manufacture of the binder, different from those stated in the present invention.

In example 7, the overestimated content of phenol-formaldehyde resin SF-010 and urotropine led to an increase in the viscosity of the binder, which, in turn, led to premature gelation of the composition, the lack of high-quality impregnation of the bag and the receipt of a defective product. In Example 11, an overestimated amount of diazobisisobutyronitrile was added to the binder, which adversely affected the macrostructure of the product.

Claims (12)

1. A binder obtained from furfural, urotropine, phenol-formaldehyde novolac resin in the following ratio of components, parts by weight:
Furfural 95-105 Urotropin 10-20 Phenol-formaldehyde novolac resin 75-90 2. The binder according to claim 1, characterized in that as its component diazobisisobutyronitrile is additionally used at its content, parts by weight: 0.1-2. 3. The method of producing a binder according to claim 1, containing stages in which:
a) form a chemical composition of urotropine and furfural
b) phenol-formaldehyde novolac resin is introduced into said composition and the resulting mixture is stirred. 4. The method according to claim 3, characterized in that the chemical composition is formed by introducing urotropine into liquid furfural and then mixing them. 5. The method according to claim 4, characterized in that the mixing is carried out at least until the dissolution of urotropin. 6. The method according to claim 3, characterized in that the resulting mixture is stirred at least until a homogeneous state is obtained and the viscosity of the mixture is stabilized. 7. The method according to claim 6, characterized in that the stabilization of the viscosity value of the mixture is determined by the condition of maintaining the viscosity of the mixture in the range of 150-350 seconds for at least 10 minutes from the first measurement of viscosity. 8. The method according to claim 3, characterized in that the components of the binder use urotropine and phenol-formaldehyde novolac resin in fragmented form. 9. The method according to claim 8, characterized in that the components are a plurality of resin particles not exceeding 15 mm in size and urotropin particles not exceeding 20 mm. 10. The method according to claim 3, characterized in that until the completion of the mixing process, diazobisisobutyronitrile is additionally introduced into the mixture at its content, parts by weight: 0.1-2. 11. The method according to claim 3, characterized in that the temperature of the composition and mixture is maintained above 30 ° C. 12. A composite material made using a binder according to claim 1.