RU2137778C1 - Mixed nitrate esters of cellulose with maleate groups as high-molecular backing for adhesive, paintwork, and polymer materials and method of preparation thereof - Google Patents

Abstract

FIELD: cellulose-based materials. SUBSTANCE: invention relates to new nitrate-maleate cellulose esters prepared from high-nitrogen cellulose nitrates or out-of-date pyroxylin powders, which can be applicable as polymer backing for glues, varnishes, and dyes with reduced combustibility and better film-forming capability. Cellulose nitrate or pyroxylin powder is subjected to condensation reaction with maleic anhydride at heating and stirring. To obtain loose hard-to-electrify product, its precipitation is effected by dosing water at the same temperature as reaction mixture (50-60 C). Combustibility of 1-mm film is 5 mm/s and water absorption 0.1 wt %. EFFECT: improved consumer's properties. 4 cl, 1 tbl, 11 ex

Description

где X = 2 - 2,9; Y = 0 - (3 - X); K + Y = 0,1 - 1; n = 200 - 450.The invention relates to new chemical compounds, specifically to mixed complex nitrate-maleate cellulose ethers of the General formula:

where X = 2 - 2.9; Y = 0 - (3 - X); K + Y = 0.1 - 1; n = 200 - 450.

 These compounds, their properties and method of preparation are not described in the literature. They can be used as the polymer base of adhesives, varnishes, paints.

A known method of producing nitrate acylate cellulose ethers by the action of carboxylic acid chlorides in the presence of an AlCl ₃ catalyst on cellulose nitrates. In this case, nitrate groups are replaced by acyl residues.

 Cellulose nitrates - an intermediate for its acylates, - Sat. "Organic chemistry and the development of chemical industries in Kyrgyzstan", Frunze, Ilim, 1976, p. 35 - 37. Sarybaeva O.I., Schelokhova L.S. R.Zh. Chemistry, 1977, 14, v. 24.

The disadvantages of the method include significant denitration and destruction of cellulose nitrates with a nitrogen content of 11.4 - 12.8% under the action of carboxylic acid chlorides in the presence of AlCl ₃ in solvents, the use of expensive reagents, protecting them from moisture, the need for regeneration.

 A closer analogue in terms of the essential features of the proposed method is a method for producing complex mixed nitric acid cellulose esters, according to which cellulose nitrate is condensed with carboxylic anhydride by heating and stirring in the presence of a diluent, followed by isolation by precipitation and filtration (SU, a.s. 883058 A , 11.23.81, B.I. N 43 1981).

 The disadvantage of this method is the use of significant quantities of expensive catalysts - antimony, tin and titanium chlorides, the need for their catch and regeneration.

 The objective of the invention is to obtain from high nitrogen nitrates with a nitrogen content of 11.4 - 13.5% or nitrocellulose pyroxylin gunpowders after the expiration of their service life of new substances - mixed nitrate-maleate cellulose ethers with reduced flammability and better film-forming properties, suitable as a polymer base glues, varnishes, paints, polymeric materials and the simplification of the process.

The problem is solved in that the cellulose nitrate, including nitrocellulose powder, is treated with maleic anhydride in the medium of protic and aprotic solvents or their mixtures at a temperature of from 50 to 110 ^o C with vigorous stirring and isolation by planting.

Новизна способа состоит в том, что НЦ в растворе с концентрацией 5 - 40% или нитратцеллюлозный порох в растворителе смешивают с малеиновым ангидридом при интенсивном перемешивании при температуре 50 - 110^oC в течение 1 - 6 часов. При температуре менее 50^oC реакция взаимодействия протекает медленно, увеличение температуры выше 110^oC приводит к осмолению реакционной массы. В качестве ангидрида карбоновой кислоты в реакции используют малеиновый ангидрид. В качестве реагента, содержащего нитраты целлюлозы, применяют нитратцеллюлозный порох.The reaction proceeds according to the scheme.

The novelty of the method lies in the fact that SCs in a solution with a concentration of 5-40% or cellulose nitrate powder in a solvent are mixed with maleic anhydride with vigorous stirring at a temperature of 50-110 ^° C for 1-6 hours. At temperatures less than 50 ^o C the reaction proceeds slowly, an increase in temperature above 110 ^o C leads to the resinification of the reaction mass. Maleic anhydride is used as the carboxylic acid anhydride in the reaction. Cellulose nitrate powder is used as a reagent containing cellulose nitrates.

 When holding for more than 6 hours, the yield of the final product is reduced. The amount of maleic anhydride is calculated based on a ratio of 0.5 to 2 mol of anhydride per nitrate group.

 The reaction is preferably carried out in acetone, which allows you to automatically adjust the temperature and simplifies the selection of the finished product.

 The quality of the finished product is influenced by the way it is isolated from the reaction mass.

In order to obtain a loose, low-electrifying product, the product is isolated from the reaction mass by a slow dosage of water with a temperature of 55-60 ^° C into the reaction mass with the same temperature, followed by filtration and washing with distilled water and drying.

 When changing the conditions for precipitation of the product from the reaction mass (for example, a dosage of cold water), an inhomogeneous powder with flakes is obtained, which has poor flowability and is highly electrified.

 If the reaction mass is poured into cold water, then a fibrous, easily clumping material is obtained, which is difficult to wash off, and is strongly electrified after drying. Depending on the solvent, the planting module is 2 to 4.

 An example of obtaining a complex mixed nitrate-maleate cellulose ether.

In a reactor equipped with a thermometer, stirrer and reflux condenser, 20 g of SC or pyroxylin powder and 18.2 g of maleic anhydride are mixed at a temperature of 55-60 ^° C in 500 ml of solvent water (e.g. acetone) with vigorous stirring. Then the reaction mass is kept for 1-6 hours at the same temperature. After exposure to the reactor, 1000 ml of water with a temperature of 50-60 ^° C is slowly dosed, maintaining the temperature of the reaction mixture at 55-60 ^° C. Then planting is performed. After precipitation, the reaction mass is cooled to 20 ^o C, filtered, washed with water until a neutral reaction of the medium, dried in air, dried and analyzed for nitrogen content and degree of polymerization.

 Mixed nitrate - cellulose maleate ester isolated in 70 - 98% yield is a powder from white (from SC) to yellow (from gunpowder).

Note:
Method 1 - loading maleic anhydride in powder form, soda is loaded in powder form after loading maleic anhydride in a solution of SC.

 Method 2 - loading a solution of maleic anhydride in a solution of SC or gunpowder.

 Method 3 - loading a solution of SC or gunpowder in a solution of maleic anhydride.

 The conditions for obtaining and properties of nitrate-maleate cellulose ethers are given in table. 1 and 2.

From these tables it follows that the ratio and order of loading of reagents, the time and temperature of the reaction, the presence of additives (NaHCO ₃ , HClO ₄ ) in the reaction mass affect the yield and degree of substitution of the acylating agent. So, in the presence of NaHCO ₃ the yield of the product decreases and the degree of substitution decreases.

 In the case of conducting the reaction in aqueous acetone, the degree of polymerization greatly decreases and product heterogeneity increases.

 The loading order, reaction time and mixing intensity strongly affect the quality and yield of the product.

 In the case of loading the NC solution into the maleic anhydride solution, the highest degree of substitution was obtained (experiments N 4, 5, 6). With an increase in the duration of the process up to 8 hours, the yield of the product decreases, so the optimal reaction time lies in the range 1-4 hours.

 The nitrogen content in the samples was determined by the mercury-free method by exposure to concentrated sulfuric acid and quantitative determination of the released nitric acid by reaction with ferrous sulfate.

 The content of acyl groups was calculated by the nitrogen content and determined by titration. The degree of polymerization was determined according to the viscometry of dilute solutions on a VPZh-1 viscometer.

 The resulting nitrate - cellulose maleate ester contains less nitrogen, therefore, has less combustibility and a lower burning rate.

 Thus, the data in the table confirm that cellulose nitrate or pyroxylin powder reacts with maleic anhydride in a solvent to form mixed nitrate-maleic cellulose esters with a yield of 70 - 93%. The reaction proceeds both in the presence of catalysts (soda, perchloric acid), and without them (pp. 1–6 of table 1).

The proposed method of obtaining more simple, since it does not require the use of expensive chlorides, catalyst AlCl ₃ , its regeneration and protection of the reaction mass from moisture.

The obtained nitrate - maleate cellulose ether (NMC) was tested to determine the content and strength properties, combustibility and moisture absorption. For this purpose, a 15% solution in acetone was obtained. The solution formed after 24 hours, while the initial SC sample with a nitrogen content of 15% forms a solution in acetone after 10-14 days. Then, the obtained varnish was applied with a brush to wood (plywood) plates and 2 overlap plates were glued together on a gluing area of 2 cm ² , and 4 layers of varnish were applied sequentially onto a smooth wooden block and the drying speed, quality of the coating formed and time to complete were monitored drying out. After that, tests were carried out to determine the adhesive strength of the glue to the tree (plywood) by shifting one plate relative to another on a tensile testing machine RMI - 0.05 - 0.1 with an electronic force meter. It was shown that the specific load causing failure upon adhesion separation using glue with NMC was 198 N / cm ² , and from the initial NC it was 170.6 N / cm ² .

 Therefore, the proposed product can be used as the polymer base of adhesives with enhanced adhesion both individually and in a mixture with SC.

 It was also shown by the gravimetric method that less moisture absorption in NMC-lacquer when holding the film from it in an aqueous medium for 24 hours than in varnish from NC. In this case, the moisture content in the NMC layer was 0.1% of its mass in dry form, and it was 0.9% for the film from the NC with the same initial concentration of the solution.

 Flammability of the same thickness in a film based on SC with a nitrogen content of 12.5% was 8 mm / s.

 Thus, the high molecular weight cellulose nitrate-maleate compound is suitable for use as a polymer base for adhesives, varnishes and paints, polymeric materials. It has less flammability and moisture absorption, increased adhesion to solid surfaces.

Claims (4)

1. Complex mixed cellulose nitrate esters with maleate groups of the General formula

where X = 2.0-2.9; y = 0 - / 3-X /; k + y = 0.1-1; n = 200-450,
as a high-molecular base adhesive, paint and varnish polymer materials with reduced flammability, increased adhesive strength and less moisture absorption.  2. A method of producing complex mixed nitric acid cellulose esters by reacting cellulose nitrate with carboxylic acid anhydride by heating and stirring, followed by isolation by precipitation and filtration, characterized in that maleic anhydride is used as the carboxylic acid anhydride.  3. The method according to p. 2, characterized in that cellulose nitrate is used as cellulose nitrate.  4. The method according to PP. 2 and 3, characterized in that, in order to obtain a loose little electrifying product, after the end of the interaction, water with the same temperature is metered into the reaction mass with a temperature of 55-60 ° C.

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