RU2569310C1 - Co-oligophenol-formaldehyde novolacs, methods for production thereof (versions) and crosslinked copolymers based thereon - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: co-oligophenol-formaldehyde novolacs have a general formula

where R=H; C₆H₅, n=5-8, m=1, (p+k):m=0,01-0,2, p:k=0.8 or 1. The method of producing the novolacs includes reacting phenol, 3,3-bis(4'-hydroxyphenyl)phthalide, 3,3-bis(4'-hydroxyphenyl)phthalimidine or 2-phenyl-3,3-bis(4'-hydroxyphenyl)phthalimidine, in weight ratio of 60:20:20 to 97:1.5:1.5, with formaldehyde. The molar ratio of the mixture of said components and formaldehyde is equal to 1:0.7. The reaction is carried out at 80-85°C in an aqueous solution in the presence of acid catalysts selected from a group comprising hydrochloric acid, phosphoric acid and oxalic acid. Crosslinked copolymers are obtained when said novolacs are cured.

EFFECT: invention enables to obtain novolacs which are stable during storage and processing, and considerably increases heat-resistance of the copolymers and strength properties thereof.

4 cl, 1 dwg, 3 tbl, 20 ex

Description

The invention relates to chemistry and technology of high molecular weight compounds, namely to condensation polymers of aldehydes and ketones with a mixture of two or more phenols, specifically:

- to oligophenol formaldehyde novolacs based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and phthalimidine-containing bisphenols of various structures of the general formula

where R = H; C ₆ H ₅ , n = 5-8, m = 1, (p + k): m = 0.01-0.2, p: k = 0.8 or 1 to obtain crosslinked copolymers;

- to methods for their preparation (options) and

- to crosslinked copolymers based on them of structure (II)

where R = H; C ₆ H ₅ ;

;

;

;

;

as structural polymers obtained by curing novolacs of the general formula (I).

The claimed technical solution can most effectively be used to obtain new crosslinked copolymers as structural polymers.

These compounds, their properties and the preparation method are not described in the literature.

Resol-type co-oligomers are known that are derived from formaldehyde, phenol, phenolphthalein and phthalimidine-containing bisphenols — the imide (or anilide) of phenolphthalein. During their curing, copolymers with high thermal characteristics and electroactive properties are formed [Machulenko L.N. and others. Plast. masses, 2007, No. 12, S. 16]. Due to these properties, they can be of interest in the manufacture of heat-resistant structural polymers for aviation and space technology, as well as electroactive materials for electronics [S.N. Salazkin et al. High Molecule. Comp., 2008, A, T. 50, No. 3, S. 399].

However, the initial resols have insufficient stability during storage. During long-term storage, there is a gradual change in such important technological characteristics as the solubility and viscosity of the solution, the content of reactive methylol groups, molecular weight, softening temperature, melt viscosity, and curing time, which complicates the technology for their preparation, as well as crosslinked copolymers based on them.

Known novolaks based on imide (or anilide) phenolphthalein [L.N. Machulenko et al. Patent RU No. 2474591, C08G 8/28, 2013], as well as phenolphthalein-containing novolacs [V.K. Shitikov et al. Patent RU No. 2443797, C08G 8/28, 2012], which have electroactive properties, high heat resistance and acceptable strength characteristics, but for some practical purposes, in particular when creating structural polymer materials for aircraft and space technology, higher strength indicators.

Of the aforementioned analogues, the closest are resol-type co-oligomers based on phenol, phenolphthalein and phthalimidine-containing bisphenols [Machulenko LN and others. Plast. masses, 2007, No. 12, S. 16].

These resoles, as described above, have a number of valuable properties, however, the urgent problem is to increase their stability during synthesis, storage and transportation.

The objective of the present invention is to obtain new sooligophenol-formaldehyde novolacs, stable during synthesis, storage and processing, to develop methods for their preparation and to obtain new crosslinked copolymers based on them, with improved strength characteristics, promising to create heat-resistant and electroactive materials.

The problem is solved by obtaining novolacs based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide and phthalimidine-containing bisphenols of various structures of the general formula (I)

where R = H; C ₆ H ₅ , n = 5-8, m = 1, (p + k): m = 0.01-0.2, p: k = 0.8 or 1, which are obtained in several ways (options).

Option 1 - the interaction of phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 3,3-bis (4′-hydroxyphenyl) phthalimidine (IFF) at a weight ratio of 60:20:20 to 97: 1.5: 1.5 with formaldehyde in a molar ratio (FF + IFP + phenol) and formaldehyde 1: 0.7 at a temperature of 80-85 ° C in an aqueous solution in the presence of acid catalysts selected from the group: hydrochloric acid, phosphoric acid, oxalic acid according to the scheme:

where n = 5-8, m = 1, (p + k): m = 0.01-0.2, p: k = 1.

Option 2 - the interaction of phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 2-phenyl-3,3-bis (4′-hydroxyphenyl) phthalimidine (AFP) at a weight ratio of 60:20: 20 to 97: 1.5: 1.5 with formaldehyde in a molar ratio (FF + AFP + phenol) and formaldehyde 1: 0.7 at a temperature of 80-85 ° C in an aqueous solution in the presence of acid catalysts selected from the group: hydrochloric acid, phosphoric acid, oxalic acid, according to the scheme:

where n = 5-8, m = 1, (p + k): m = 0.01-0.2, p: k = 0.8,

Kt is an acid catalyst (hydrochloric acid or phosphoric acid or oxalic acid).

The figure 1 shows the IR spectrum of novolak based on phenol, phenolphthalein and phenolphthalein imide (example 3, table 1).

The problem is also solved by crosslinked copolymers based on novolac structure (II).

where R = H; C ₆ H ₅ ;

;

;

;

;

Crosslinked copolymers are prepared according to a known method by pre-curing novolak in the presence of a hardener and subsequent hot pressing at a temperature of 180 ° C for 1 hour under a pressure of 10 MPa [A. Knop, W. Sheyb. Phenolic resins and materials based on them. M., Chemistry, 1983, S. 158].

As starting substances for the preparation of novolacs, the following were used: phenol GOST 23519-93, phenolphthalein (3,3-bis (4′-hydroxyphenyl) phthalide) (FF) from ACROS, imide phenolphthalein (3,3-bis (4′-hydroxyphenyl) phthalimidine (IFF), obtained according to the known method [Morgan PWJ Polymer Sci. A. 1964. V 2. P. 437], phenolphthalein anilide (2-phenyl-3,3-bis (4′-hydroxyphenyl) phthalimidine) (AFP) obtained by a known method [Albert R // Chem. Ber. 1893. V. 26. S. 3077].

The inventive sooligophenol formaldehyde novolacs, methods for their preparation and crosslinked copolymers based on them have not yet been described.

The invention is illustrated by specific examples of its implementation, below.

Obtaining oligophenol formaldehyde novolak based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 3,3-bis (4′-hydroxyphenyl) phthalimidine (IFF) in a weight ratio of 97: 1.5: 1.5

Example 1. To 14.1 g (0.15 mol) of phenol add 0.22 g (0.0007 mol) of FF, 0.22 g (0.0007 mol) of IFF, 8.5 ml of 34% formalin containing 3 2 g (0.11 mol) of formaldehyde and 0.3 ml of concentrated hydrochloric acid. The reaction mass is heated with stirring in a water bath at 80-85 ° C for 1 h until the reaction mass is clearly separated into two layers (water and resin). The aqueous layer is separated by decantation, and the resin is repeatedly washed with hot water and dried in an oven at 90-100 ° C. Yield 78.4%, _Tmm. - 94-96 ° C. Novolac is soluble in acetone, ethanol, n-propanol, dioxane. The content of elements,%: C - 79.4; H 5.5; N is 0.1. Curing time with urotropine at 180 ° C - 31 sec, at 150 ° C - 1 min 28 sec.

Similarly obtained with a yield of 79.6-95.8% novolaki with other ratios of the starting components (novolaki 2 and 3 - examples 2 and 3 in table 1).

To confirm that other acids can be used as catalysts along with hydrochloric acid, Table 1 shows comparative data for novolak 3 obtained in the presence of phosphoric acid (Example 4). From the above data it is seen that, regardless of the acid catalysts used, novolak 3 samples obtained in the presence of hydrochloric acid (example 3) or phosphoric acid (example 4) have similar characteristics.

Obtaining oligophenol formaldehyde novolak based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 2-phenyl-3,3-bis (4′-hydroxyphenyl) phthalimidine (AFP) in a weight ratio of 95: 1.5 : 1,5

Example 5. To 25.4 g (0.27 mol) of phenol, 0.4 g (0.001 mol) of FF, 0.4 g (0.001 mol of AFF, 17.5 ml of 30% formalin containing 5.7 g (0.19) are added mol) of formaldehyde and 0.6 ml of concentrated hydrochloric acid.The reaction mass is heated with stirring in a water bath at 80-85 ° C for 3 hours until the reaction mass is clearly separated into two layers (water and resin). The aqueous layer is separated by decantation, and the resin is washed many times with hot water and dried in an oven at 90-100 ° C. Yield 84.9%, _Tm — 95-97 ° C. Novolak is soluble in acetone, ethanol, n-propanol, dioxane. cops,%: C - 77.0, H - 5.9, N - 0.2. Curing time at 180 ° C - 2 min 20 sec, at 150 ° C - 4 min 45 sec.

Similarly obtained with the release of 86-90% novolaks with other ratios of the starting components (novolaks 5 and 6 - examples 6 and 7 in table 1).

The resulting co-oligomers have a high cure rate. So for novolacs 4-6, the curing time of urotropine at 150 ° C does not exceed 30 seconds (for curing the analogue, it takes about 2 minutes), which is of great importance in solving some practical problems, in particular, in the preparation of electroactive films.

The structure of the obtained novolacs is confirmed by IR spectra. As an example in FIG. 1 shows the IR spectrum of novolak 3 (example 3, table. 1).

The presence of both phthalide and phthalimidine cycles in novolak is confirmed by the presence of intense bands in its IR spectrum at 1736 cm ^-1 and 1698 cm ^-1 due to stretching vibrations ν (C = O) of the phthalide and phthalimidine cycles, respectively.

The obtained novolaks in comparison with the known analogue (resols) have an unlimited shelf life and, therefore, they are more technologically advanced in the synthesis and subsequent preparation of copolymers based on them.

Based on sooligophenol formaldehyde novolacs by curing with urotropine (HMTA) in an amount of 10% by weight of novolak, with dimethylol derivative of p-cresol (DMPC) - 3,5-di (hydroxymethyl) -4-methylphenol in an amount of 36%, as well as with phenolic resol SF -3021 in the amount of 100% obtained crosslinked copolymers.

Example 8. Novolak 1 (7 g) is melted at a temperature of 160 ° C, 0.7 g (10% of the amount of novolak) of urotropine is added to the melt as a hardener, and the obtained melt is heated with constant stirring for 2 min 10 sec. The resulting mass is cooled, ground in a mortar, and from the obtained powder by hot pressing at a temperature of 180 ° C and a pressure of 10 MPa, pressed samples of a crosslinked copolymer are obtained, for which the strength characteristics (specific toughness and breaking stress at bending) are shown in Table 2.

Example 20. Novolak 1 (6 g) is melted at a temperature of 160 ° C, 2.2 g (36% of the amount of novolak) DMPC as a hardener is added to the obtained melt, and the obtained melt is heated with constant stirring for 2 min 10 sec. The resulting mass is cooled, ground in a mortar, and from the obtained powder by hot pressing at a temperature of 180 ° C and a pressure of 10 MPa, pressed samples of a crosslinked copolymer are obtained, for which the strength characteristics (specific toughness and breaking stress at bending) are shown in Table 2.

Similarly, by curing novolacs 2-6 with urotropine or DMPC, crosslinked copolymers are obtained (examples 10-19 in table 2), the strength characteristics of which are given in table 2.

As can be seen from the data presented, the obtained cross-linked copolymers have significantly higher strength characteristics in comparison with the known analogue (tensile bending stress and specific impact strength reach 81.6 MPa and 4.9 kJ / m ² , respectively, whereas the analog they do not exceed 32.1 MPa and 1.2 kJ / m ² ).

The possibility of using various hardeners in the preparation of crosslinked novolak-based copolymers makes it possible to control the course of the curing process, the structure and properties of the resulting copolymers depending on practical tasks, which is also an important advantage in comparison with similar resols.

The resulting crosslinked copolymers (II) also have high heat resistance, which is determined by the method of dynamic thermogravimetric analysis at temperatures T ₁ and T ₂ at which the weight loss of the samples of the copolymers during heating is 10 and 20%. The results are presented in table 3.

From the presented data it can be seen that the obtained copolymers have high thermal characteristics (T ₁ and T ₂ are 370-455 and 482-510 ° C, respectively) and in terms of T ₁ they exceed the known analogue (for the obtained copolymers, T ₁ reaches 455 ° C, while for the analogue the value of this indicator does not exceed 400 ° C).

Thus, sooligophenol-formaldehyde novolacs are obtained which are stable during synthesis, storage and processing. Methods for their preparation are developed. Based on novolacs, cured copolymers with significantly higher strength characteristics than with the known analogue, as well as with higher heat resistance, were obtained by curing them. Copolymers can be used to create highly effective heat-resistant and electroactive structural polymer materials.

The technical result of the claimed invention are previously unknown sooligophenol formaldehyde novolaks based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and phthalimidine-containing bisphenols of various structures, stable during synthesis, storage and processing, methods for their preparation and crosslinked copolymers with strength indicators, significantly superior to the known analogue, as well as higher heat resistance in comparison with it, which allows the use of the obtained copolymers to create a heat-resistant x structural materials with high strength and thermal characteristics.

Claims (4)

1. Soyoligophenol formaldehyde novolacs based on phenol, 3,3-bis (4′-hydroxyphenyl) phthalide and phthalimidine-containing bisphenols of various structures of the general formula

where R = H; C ₆ H ₅ , n = 5-8, m = 1, (p + k): m = 0.01-0.2, p: k = 0.8 or 1 to obtain crosslinked copolymers. 2. The method of producing novolac according to claim 1, which consists in the interaction of phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 3,3-bis (4′-hydroxyphenyl) phthalimidine (IFF) in their weight ratio from 60:20:20 to 97: 1.5: 1.5 with formaldehyde in a molar ratio (FF + IFF + phenol) and formaldehyde 1: 0.7 at a temperature of 80-85 ° C in an aqueous solution in the presence of acid catalysts, selected from the group: hydrochloric acid, phosphoric acid, oxalic acid. 3. The method of producing novolac according to claim 1, which consists in the interaction of phenol, 3,3-bis (4′-hydroxyphenyl) phthalide (FF) and 2-phenyl-3,3-bis (4′-hydroxyphenyl) phthalimidine (AFP) when their weight ratio is from 60:20:20 to 97: 1.5: 1.5 with formaldehyde at a molar ratio (FF + AFP + phenol) and formaldehyde 1: 0.7 at a temperature of 80-85 ° C in an aqueous solution in the presence of acid catalysts selected from the group: hydrochloric acid, phosphoric acid, oxalic acid. 4. Crosslinked Novolac copolymers according to claim 1 of the general formula

where R = H; C ₆ H ₅ ;

;

;

as structural polymers.

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