NO139835B - DEVICE FOR LOCKING A REVERSE WINDOW WINDOW FRAME IN A SPECIFIC LOCKING POSITION - Google Patents

Description

Polymerization of acrylonitrile.

The invention relates to a new method for producing polymers or copolymers of acrylonitrile.

Polymers of acrylonitrile and copolymers of acrylonitrile with other monoethylenically unsaturated compounds are known. These polymers and copolymers have been found to have a wide application in the production of many valuable commercial products such as e.g. synthetic rubbers and more especially artificial fibres.

Difficulties have arisen in the polymerization or copolymerization of acrylonitrile, and considerable work has gone into developing a practical, economical method for producing these very useful polymers and copolymers. There are a number of reports relating to the polymerization catalysts in an aqueous polymerization medium, and in particular a redox type of catalyst consisting of oxidizing and reducing substances. The oxidizing substances include oxygen-releasing peroxides, which have the ability to initiate the polymerization themselves as persulphate and perborate as described in U.S. Pat. patent no. 2,436,926 or substances which are able to initiate the polymerization themselves such as chlorates, potassium permanganate or secondary metal salts. The reducing substances are oxidizable sulfoxy compounds and others. Generally speaking, the redox type of polymerization catalysts is not just a combination of any oxidizing and reducing substance, but unique mixture of two substance types.

The applicability of a polymerization catalyst depends on the physical and chemical properties of the produced polymer as well as the ability to initiate polymerization. It is believed to be desirable for the catalyst that polymers which have superior physical properties, and are compatible with desired articles, are formed quickly with good yield.

A catalyst can be used which can accelerate the polymerisation at a practical speed, temperature, ease of control of the reaction system using a practical amount of catalyst from an economic point of view without undesirable side reactions (e.g. formation of yellow polymer) during polymerisation the one.

It is an aim of the present invention to provide a polymerization or copolymerization process of acrylonitrile in the presence of a new catalyst.

According to the invention, the new catalyst consists of hydroxylamine sulphonates and which are used together with known inorganic compounds which have a tetravalent sulfur atom. The present catalyst has high polymerization initiation ability and can form polymers or copolymers that have a desired degree of polymerization with easy control of operation and be starting materials for acrylic synthetic fibers that are preferable both with regard to white color and heat stability of the white color.

The hydroxylamine sulfonic acid is hydroxylamine monosulfonic acid with the formula

and hydroxylamine disulfonic acid with the formula but the latter acid hydrolyzes rapidly with an aqueous solution of pH 1.5-4 in the monosulfonic acid, and both acids are equivalent in the present invention. The amine sulfonic acid of the formula does not initiate polymerization after it is mixed with tetravalent sulfur-containing inorganic compounds. Salts of such acids are sodium salts, potassium salts, ammonium salts and others, the former two being preferred because of good solubility. Inorganic compounds that have a tetravalent sulfur atom are sulfur dioxide,

means monovalent metals.

Thiosulfate, which is one of the commonly oxidizable sulfoxy compounds, is believed to have the structural formula

because of its behavior, and it is outside the scope of inorganic compounds having tetravalent sulfur atom, and no activity has been found to initiate polymerization after it is mixed with the hydroxylamine sulfonate. Organic compounds containing sulfur atoms such as diethylsulfite or toluenesulfinic acid show no economically useful initiating activity.

As mentioned above, the present catalyst is composed of salts of hydroxylamine monosulfonic acid or hydroxylamine disulfonic acid and inorganic compounds containing a tetravalent sulfur atom. The first-mentioned compound can be used in an amount of 0.1-5.0% by weight. of the total amount of monomer and the hydroxylamine sulfonic acid can be a hydroxylamine monosulfonic acid or the corresponding mole of hydroxylamine disulfonic acid. The latter compound of inorganic substances containing a tetravalent sulfur atom can be used in the range from 1-10% by weight. of the total amount of monomer. The ratio of the former component to the latter can be varied within the range from 5:1 to 1:30 parts by weight. Generally speaking, the amount of polymerization catalyst can be varied depending on the polymer's physical properties, polymerization rate and other economic factors. The polymerization can be carried out above 10° C, preferably at 40-75° C. The polymerization can hardly be carried out economically below 10° C, because the degree of decomposition of the polymerization catalyst becomes too unnecessarily large to form a desired polymer at too high a temperature.

It is required for the present catalyst that the polymerization is carried out at pH 1.5-4.0, otherwise the polymerization initiation ability of the catalyst according to the invention is reduced and eventually lost. In order to maintain such a pH, inorganic or organic acids such as sulfuric acid, nitric acid, hydrochloric acid, oxalic acid and the like can be used.

The present polymerization is carried out in an aqueous dissolution medium, and the monomer substance and water must be filled in a reactor in a ratio of 1:2 to 1:15 parts by weight. If the ratio of water to monomer becomes lower, difficult polymerization heat is removed, and the produced polymer slurry becomes more viscous. But the polymer can be produced in good yield, the production capacity per volume unit of reaction vessel increases, and further less polymerization catalyst per unit weight of monomer is neces-

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you. The polymer formed has excellent physical and chemical properties when the amount of water is lower, but it is advantageous to determine the ratio taking into account what has been mentioned above.

The polymerization is preferably carried out in the absence of oxygen, and therefore air in a reactor should be replaced with an inert gas such as e.g. nitrogen before the polymerization starts. The oxygen reduces the degree of polymerisation and affects the physical and chemical properties of the produced polymer.

Heavy metals such as iron, copper etc., which are usually included in the polymerization system, have a slight effect on the polymerization reaction, as well as on the physical properties of the final polymer. This is one of the advantages of the present process. When a common catalyst was used such as ammonium persulphate, sodium bisulphite or ammonium persulphate thioglycolic acid, it can be seen from the following table that the reduced viscosity of the produced polymer is strongly influenced by the presence of heavy metals.

From the figures above, it appears that a reactor made of stainless steel as well as a glass-lined reactor can be used. Dispersants and/or emulsifiers may be present in the polymerization system.

The present invention is applied to the production of acrylonitrile polymer and copolymers of mixtures of monoethylene-unsaturated compounds containing at least 85% by weight of acrylonitrile and up to 15% by weight of a copolymerizable compound. According to the invention, monoethylenic unsaturated compounds which are copolymerizable with acrylonitrile, e.g. the following: styrene and alkyl substitution for - connection of these, e.g. p-methylstyrene, p-ethylstyrene, 2,4-diethylstyrene, etc., vinyl esters and especially vinyl esters of saturated aliphatic monocarboxylic acids, e.g. vinyl acetate, vinyl propinate, vinyl butyrate, etc., vinyl and vinylidene halides, e.g. vinyl chloride, vinyl fluoride, vinyl bromide, vinylidene chloride, vinylidene fluoride, vinylidene bromide, etc., alcohols of the allyl type, e.g. allyl alcohol, metalyl alcohol, etallyl alcohol, etc., acrylic acid and its alkyl substitution compound, e.g. acrylic acid, methacrylic acid, ethacrylic acid, |3,|3-dimethylacrylic acid, etc., and alkyl esters of such acids, e.g. methyl acrylate, ethyl acrylate, propyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate, etc. and aminoalkyl esters of such acids, e.g. (3-diethylaminoethyl methacrylate, p-dimethylaminoethyl methacrylate, γ-dimethylaminopropyl acrylate, etc., and sulfo-alkyl esters of such acids, e.g. 3-sulfopropyl methacrylate, 2-sulfoethyl methacrylate, 2-sulfoethyl acrylate, etc. and amides of such acids , e.g. acrylamide, methacrylamide, ethacrylamide, etc., monoalkyl substitution compounds of acrylonitrile, e.g. methacrylonitrile, (3,|3-dimethylacrylonitrile, etc., vinyl compounds containing sulfonic acid groups, e.g. vinylsulfonic acid , allylsulfonic acid, metalylsulfonic acid, p-styrenesulfonic acid, w-styrenesulfonic acid, etc., vinyl compounds containing a basic nitrogen atom, e.g. 2-methyl-5-vinylpyridine, 5-ethyl-2-vinylpyridine, 4,6-dimethyl- 2-vinylpyridine etc., unsaturated polycarboxylic acids and their alkyl esters, e.g. itaconic acid, γ-hutyrene-α, γ-dicarboxylic acid, dimethyl itaconate, diethyl maleate, dibutyl itaconate, etc. Two or more copolymerizable monomers can be used if desired.

The polymer or copolymer produced by the method according to the invention is very useful for acrylic synthetic fibers which have excellent physical properties. The polymer or copolymer can also be used for film or other articles.

The present invention will be explained in more detail with the help of some examples. The reaction participants' parts are always given in parts by weight if nothing else is specifically stated.

Example 1.

A mixture of the above substances was filled into a glass-lined closed reactor equipped with a mechanical stirrer and a jacket, and then nitrogen was passed through to drive off air. The temperature was maintained at 60°C with stirring for 4 hours to form a polymer slurry of pH 2.8. The porridge was removed from the reactor and dehydrated immediately afterwards. The slurry was washed well with water and again dehydrated by a centrifugal hydroextractor and dried at 50°C to form white polymer. Yield: 85 percent. The reduced viscosity of the polymer was 1.40 at 35° C. in 0.2 g/100 cm* dimethylformamide. The polymer was dissolved at 0°C in nitric acid (70% by weight) free of nitric acid to obtain a 24 g/100 cm<3> solution, and then extruded at a speed of 4 m/min. in an aqueous nitric acid solution (30% by weight). The extruded fibers were washed with water, drawn 7.5 times in hot water of 100°C and dried at 80°C to form fibers with the following properties:

The fibers had a good degree of whiteness and thermal stability and were barely colored after moist heat treatment for 10 min. at 120°C.

Example 2.

The above substances were fed continuously into a glass-lined reactor equipped with a jacket and a stirrer. The temperature was maintained at 55° C. and the feed was controlled so that the average time period used was 6.5 hours. Polymer slurry was continuously discharged from the reactor and had a pH of 2.7. The polymeric slurry was processed as indicated in Example 1 to give white polymer in 8% yield. The reduced viscosity of the polymer was 1.50, determined as indicated in example 1. The fibers were produced from the polymers as in ex. 1, and had

Fineness Tensile strength Elongation 2.70 d 2.57 g/d 25 per cent It also had a good degree of whiteness and thermal stability.

Example 3.

A mixture of the above substances was polymerized at 65° C. for 4 hours as indicated in Example 1. The polymeric slurry had a pH of 2.8 and a white polymer with a reduced viscosity of 1.54 was produced in 87% yield . If sulfuric acid was replaced with sodium hydroxide and the reaction was carried out at pH 4.5, the reaction mixture turned brown and no polymer appeared at 65° C. within 10 h.

Example 4.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 h as indicated in example 1, and a polymer slurry of pH 2.5 was produced, from which a white polymer with a reduced viscosity of 1.45 with 89 pst was produced . dividend. When no sodium hydroxylamine mono-sulfonate or sodium bisulfite was used, a polymer was obtained with less than 5% yield after a polymerization at 60° C. for 10 h.

Example 5.

A mixture of the above-mentioned substances was polymerized at 55° C. for 4 hours as indicated in example 1, and a polymer slurry with pH 2.4 was obtained, from which a white polymer with a reduced viscosity of 1.71 in 85 percent was obtained. dividend.

Example 6.

A mixture of the above substances was continuously fed into a stainless steel reactor equipped with a stirrer and jacket. The temperature was kept at 55° C. and the average residence time for the reagents was controlled to 4 h. Polymer slurry at pH 2.9 was continuously discharged from the reactor. The slurry was processed as in Example 1 to form white polymer with a reduced viscosity of 1.41 in 75% yield. The polymer was dissolved at 0° C. in 70% by weight nitric acid. free of sulfuric acid to obtain a 25 g/100 cm 3 solution which was extruded at 0° C. into an aqueous nitric acid solution (30 wt.%) at a speed of 5 m/min. The fibers thus formed were washed with water, stretched 8 times in hot water at 100°C and dried at 80°C to obtain fibers with

The fibers were dipped in an aqueous dye bath containing 0.25 wt. Severon green B in a bath degree of 40, temperature of 100° C for 1 h and absorbed 6.5 wt. of the dye per fiber weight. The fibers had a high whiteness and were barely colored after moist heat treatment in 120° steam for 10 min.

Example 7.

A mixture of the above-mentioned substances was polymerized at 70° C. for 4 h as indicated in example 1, and a polymer slurry with pH 2.6 was produced from which white polymer with a reduced viscosity of 1.35 was produced in 87% yield .

Example 8.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 hours as indicated in example 1, and a polymer slurry with pH 2.4 was produced from which white polymer with a reduced viscosity of 1.35 in 86 percent was produced. dividend.

Example 9.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 hours as indicated in example 1, and a polymer slurry with pH 2.5 was produced, from which white polymer with a reduced viscosity of 1.63 in 70 percent was produced. dividend.

Example 10.

A mixture of the above-mentioned substances was polymerized at 50° C and an average residence time of 6.5 h as stated in example 2. A polymer slurry with a pH of 2.4 was produced, from which a white polymer with a reduced viscosity of 1, 65 in 80 per cent dividend.

Example 11.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 h as indicated in example 1, and a polymer slurry of pH 2.6 was produced, from which white polymer with a reduced viscosity of 1.63 was produced in 90% yield .

Example 12.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 hours as indicated in example 1, and a polymer slurry of pH 2.7 was produced from which a white polymer with a reduced viscosity of 1.58 in 92 percent was produced. dividend.

j Example 13.

A mixture of the above-mentioned substances was polymerized at 45° C and an average residence time of 4 h as indicated in example 2, and a polymer slurry with pH 2.7 was obtained, from which a white polymer with reduced viscosity 1 was produced, 41 in 81 per cent dividend. The polymer was dissolved at 0°C in 70% by weight nitric acid free of nitric acid to form a 26g/100cc solution and then extruded at 0°C into an aqueous nitric acid solution (30% by weight) at a rate of 5m/min. The fibers thus prepared were washed with water, drawn 7 times in a hot bath at 100°C and dried at 80°C to form fibers with

The fibers were dipped in an aqueous dye bath containing 0.25 parts by weight of severon green B at a bath degree of 40, a temperature of 100° C. for 1 hour and absorbed 45 percent by weight of the dye per fiber weight. The fibers had a high degree of whiteness and were barely colored after moist heat treatment with 120° steam for 10 min.

Example 14.

sulfuric acid shown in the following table.

A mixture of the above substances was polymerized at a temperature of 55° C and an average residence time of 4 hours. The results were as follows: Example 15. i

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 hours as in example 1, and a polymer slurry with a pH of 2.6 was produced, from which a white polymer with a reduced viscosity of 0.95 was produced. with 95 percent yield.

Example 16.

A mixture of the above-mentioned substances was polymerized at 60° C. for 4 hours as given in example 1, and a

>olymer slurry with pH 2.8, from which white polymer with a reduced viscosity of 1.62 is produced in 90 percent yield.

Example 17.

A mixture of the above substances was polymerized at 55° C. for 6 hours as

stated in Example 1, and a polymer slurry with pH 2.3 was formed, from which white polymer with reduced viscosity 1.44 was produced in 80% yield.

Example 18.

A mixture of the above-mentioned substances was polymerized at 60° C for 4 h and a polymer slurry with pH 1.9 emerged, of which

white polymer with reduced viscosity 2.35 was produced in 85% yield.

Claims (1)

Process for the polymerization of acrylonitrile or a mixture containing at least 85% by weight of acrylonitrile and up to 15% by weight of at least one copolymerizable ethylene-unsaturated monomer in an aqueous medium with a pH of 1.5-4.0 in the presence of a catalyst selected from inorganic compounds containing tetravalent sulphur, such as sulfur dioxide, bisulphite, metabisulphite, sulphite, hyposulphite, etc., characterized in that salts of hydroxylamine monosulphonic acid or hydroxylamine disulphonic acid are used together with said sulphur-containing catalyst.