DE2365041C3 - Radiation-shielding fibers made of phenolic resins, processes for their production and their use - Google Patents

Description

The invention relates to radiation shielding Fibers made from phenolic resins and a process for their production and their use Fibers.

In recent years, various industries such as chemical industry, medical Sector, nuclear reactors or the like, radioactive substances do increasingly handled. the People working in these areas must wear a radiation shielding device when carrying out their work Wear clothing. So far, radiation shielding clothing has been used for this purpose, the made of a textile material, for example woven, knitted or knitted cloths with a Radiation-shielding material made of lead powder coated which had been applied with the help of a resin binder. However, are Textile materials with such a cover are not only very heavy, but also completely impermeable to air, so that they are not only uncomfortable to wear but also unhealthy. In addition, so far is the Radiation shielding effect is not completely sufficient. If a textile material as radiation shielding material should be used, there are considerable in terms of the choice of material Restrictions as there are textile materials in which, as a result of exposure to radiation, a Deterioration in the properties of the material takes place.

There are metal sulfide-containing threads, fibers or foils known, which by spinning one of the compounds of the arsenic and / or antimony containing viscose and treating threads and fibers thus obtained or foils - without alkaline aftertreatment - with aqueous solutions of the salts of such metals, their Sulphides are sparingly water-soluble, can be obtained (cf. DT-AS 12 42 791). The products obtained in the process however, do not have a sufficient radiation protection effect and also have a reduced one Strength.

The object of the invention is therefore to create new radiation-shielding fibers made from phenolic resins with excellent radiation protection effect, with no deterioration in the properties of the fibers occurs due to exposure to radiation, these fibers being treated by a simple process can be manufactured at low cost.

According to the invention radiation-shielding fibers made of phenolic resins are created, thereby are characterized in that the fibers consist of a metal atom with a high radiation protection capacity Containing polymer consist of 100 to 70 percent by weight of a cured novolak resin with a content of 0.1 to 4.0 m-equivalent / g-fiber of a sulfonic acid group and with a degree of hardening of 5 to 30%, and from 0 to 30% by weight composed of a fiber-forming thermoplastic synthetic polymer, the metal atoms in an amount of 0.1 to 3.5 m-equivalent / g-fiber in the ionic state chemically to the sulfonic acid group of the Novolak resin are bound.

The radiation-shielding fibers made of phenolic resins are manufactured according to the invention by a method produced, which is characterized in that one

(a) Fibers made from a polymer that is 100 to 70 Weight percent of a novolak resin and from 0 to 30 weight percent of a fiber-forming resin thermoplastic synthetic polymers, a curing treatment with a Subjecting hardeners to a degree of hardening of 5 to 30%,

(b) the cured fibers obtained are sulfonated and

(c) the resulting hardened polymer fibers containing sulfonic acid groups, if necessary for transfer the sulfonic acid groups are treated in the form of alkali salts and then the fibers with a solution for introducing metal ions with a large radiation protective ability of the metal atoms in the polymer treated.

The radiation shielding used according to the invention Fibers made from phenolic resins differ fundamentally from the known fibers in which the surface of a textile material with a powder

a radiation shielding metal or an oxide thereof, together with a resinous one Binder is covered

The method according to the invention is simple to carry out and can be used on an industrial scale Application.

The novolak resin used according to the invention is uncured and is in the molten starting resin mixture meltable and can be hardened with a hardening agent after melt spinning or nozzle spinning will.

Methods for making novolak resins are known

Such resins can be produced by reacting a phenol with an aldehyde under heat in the presence, an acidic or basic catalyst. Usually the novolak resins have a numerical average molecular weight from about 300 to about 2000. Also, if desired those with a larger molecular weight, for example up to about 5000, can be prepared. As is well known The modified novolak resins of the predominant novolak type can be modified by any desired combination the reaction of the novolak type and the reaction of the resohype are obtained and also used will. Furthermore, all desired combinations of phenols and aldehydes can be used and different novolak resins, each made up of different combinations Phenol and aldehyde derived can be used together.

The phenols used to make the phenolic resins are most commonly phenol and cresol. However other phenols can also be used. Examples of phenols are o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 2,4-xylenol, 2,6-xylenol, ' 3,4-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, p-phenylphenol, p-tert-butylphenol, p-tert-amylphenol, bisphenol A. Resorcinol and mixtures of two or more of these materials with each other.

In addition, phenols containing at least one halogen atom, preferably up to 3 halogen atoms, contained on the benzene ring. Examples of such halogenated phenols are o-chlorophenol, m-chlorophenol. p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, 3,5-dichlorophenol, 3,5-dibromophenol, 3-chloro-5-bromophenol, 2,3-dichlorophenol, 3,4-dichlorophenol, 2,3-dibromophenol, 3,4,5-trichlorophenol, 3,4,6-tribromophenol and 2,3,6-tribromophenol. o-chlorophenol, m-chlorophenol, p-chlorophenol are particularly preferred. These halogenated phenols are preferably used in combination with the Phenols specified above are used instead of the sole use. The halogenated Phenols can be used in amounts of at least 3 percent by weight, preferably 10 to 80 percent by weight and more preferably 20 to 60 percent by weight based on the total weight of the phenols, are present. When phenols containing these halogenated phenols are used, phenolic fibers can be used with more improved heat resistance can be obtained.

The most common aldehyde used for polycondensation with the above phenols is from formaldehyde, but other aldehydes such as p-formaldehyde, hexamethylenetetramine and furfural can also be used can also be used.

Various acidic or basic catalysts can be used for the phenolic resin formation reactions will. Examples of fjaure catalysts include all known organic or inorganic acids, such as hydrochloric acid, nitric acid, sulfuric acid, Phosphoric acid, zinc chloride, aluminum diloride, Formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid or phthalic acid, the basic catalyst can, for example, consist of ammonia, sodium hydroxide, Potassium hydroxide or hexamethylenetetramine.

The uncured novolak resins obtained by the addition or condensation of phenols and aldehydes can be used as such for fiber production. It is also possible according to the invention Mixtures of such novolak resins as the main component with other fiber-forming thermoplastic resins use synthetic polymers. In the mixture, the amount of further fiber-forming thermoplastic may be used synthetic polymer not more than 30 percent by weight but not less than 0.1 percent by weight, based on the total weight of the mixture. The amount of fiber-forming thermoplastic synthetic polymer is preferably 25 to 2 percent by weight, in particular 20 to 5 weight percent and most preferably 15 to 10 weight percent based on the total weight of the mixture.

The fiber-forming thermoplastic synthetic polymer, which is the further component of a thread can form according to the invention is preferably a polyamide, polyester, polyolefin or polyurethane. Other fiber-forming thermoplastic synthetic polymers can also be used according to the invention will.

The term "fiber-forming thermoplastic synthetic polymer" here does not just mean that individual polymers listed above, but also mixtures of different polymers, Copoiymeren therefrom with smaller amounts of other copolymerized comonomers or mixtures of same polymers with different monomer combinations or molecular weights.

Of these fiber-forming thermoplastic synthetic polymers, the polyamides are in view of on their good dispersibility in novolak resin, their effects on improving the spinnability of the Novolak resin or the low likelihood of adverse effects on the flame resistance and anti-melt properties of the novolak resin and the like are particularly preferred.

Specific examples of fiber-forming thermoplastic synthetic polymers include polyamides such as Nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 611, nylon 612, or mixtures of two or more of these polymers with one another. Polyester such as polyethylene terephthalate, Polyesters derived from the same components, such as polyethylene terephthalate, where some of the ethylene glycol has been replaced by other known glycols, polyesters derived from the same constituent elements, such as polyethylene terephthalate, wherein the terephthalic acid is partially replaced by ortho- or meta-phthalic acid, other known aliphatic Dicarboxylic acids or mixtures of two or more of these materials is replaced with one another, Polyesieräther, such as polyethylene hydroxybenzoate, elastomeric polymers such as polyurethane, and also polyolefins, such as Polyethylene, polypropylene and ethylene-propylene copolymers or mixtures of two or more of these

Materials with each other.

The term "phenolic resin" thus includes not only the novolak resin alone, but also mixtures of the Novolak resin with up to 30 percent by weight, based on the total amount of the mixture, furthermore fiber-forming thermoplastics discussed above synthetic polymer.

The phenolic resin can be converted into fibers by melt spinning or jet spinning.

Spinning devices and spinning operations are well known ₀ and therefore need not be described here. The molten mixture fed to melt spinning may contain hexamethylenetetramine in an amount suitable for inducing partial curing of the mixture, but not detrimental to the melt spinning of the molten mixture containing an uncured novolak resin, for example an amount less than 5 Weight percent based on the uncured »novolak resin. However, the incorporation of hexamethylenetetramine is not always necessary, and it is sufficient that the melt-spun filament is hardened using the hardening agents described above.

The known treatments, such as filtration or defoaming of the molten mixture, can at any point in time before the molten mixture reaches the spinneret. the Spun thread can be hardened after winding or at any time before winding. The winding speed is usually around 200 to 2500 meters per minute. Usually slightly faster take-up speeds than the spinning speed give favorable results for the strength of the thread obtained.

Known oils or n-paraffinic hydrocarbons and the like can be used as spin oil preparations.

The hardening of the melt-spun thread can be carried out in various ways. The melt-spun uncured phenolic resin filaments may be at room temperature to an elevated temperature of about 150 ⁰ C according to methods known per se cured.

The curing process may vary according to the type and amount of phenolic resin, the type and amount of thermoplastic synthetic resin, the denier of the thread, the kind and amount of the curing agent and the like. to get voted.

The most common hardening agent used is formaldehyde. Other hardening agents can also be used can be used and examples thereof are aldehydes and aldehyde-generating substances such as paraformaldehyde. Hexamethylenetetramine, furfural, chloral or glyoxal and compounds that contain formaldehyde Heat form, such as trioxane, tetraoxane or polyoxymethylene.

Generally, the melt-spun filaments are placed in a bath. which enthäu and at room temperature or at temperatures near room temperature, for example 5 to 45 ° C is preferably maintained from 10 to 40 ⁰ C, dipped or the curing agent and the above-mentioned basic or acidic catalysts. allowed to pass and at a temperature of, for example 60 to 140 ⁰ C, preferably 70 heat-set to 110 ⁰ C. The contact between the threads and the liquid containing the hardening agent is not restricted to one of the specified methods, but other methods such as spraying on or vapor deposition can also be used.

An example of a liquid that contains the hardener contains, is an aqueous solution with 5 to 45%, preferably 15 to 30% formaldehyde, their pH was adjusted to 8 to 13, preferably 5 to 11, by adding the basic catalyst.

Another example of a liquid containing the hardening agent is an aqueous solution with 0.5 to 40%, preferably 1 to 35% formaldehyde and 0.1 to 35%, preferably 1 to 20%, of one of the acidic catalysts listed above.

In a further hardening process, the threads are made of hexamethylenetetramine by heating in a mixed bath and an n-paraffinic hydrocarbon hardened at 50 to 150 "C. According to another Embodiment are the threads in the smoke or steam, which formaldehyde and a basic or containing acid catalyst

Preferably, after contacting the melt-spun threads with the hardening agent the temperature gradually increased to the thermosetting temperature. For example the temperature is on the desired point at a rate of about 3 to 20 ° C / hour. since the beginning of heat curing elevated. On the other hand, the temperature in the initial stage of heat setting becomes as low as possible held and a substantial increase in temperature is caused by the intermediate stage of thermosetting carried out until the finally desired temperature is obtained, or there will be a substantial increase in temperature carried out at the time of the initial stage of thermosetting, while the final Temperature is kept at as low a value as possible and this state is maintained. After the hardening operation, the threads are washed with water and dried so that the final thread product is obtained.

The heat setting time is desired in accordance with the manner of performing the Curing operation, the heating temperature, the type and concentration of the curing agent and the Catalyst, the type and amount of novolak resin, the type and amount of thermoplastic synthetic Polymers, the titer of the threads and the like. Usually it is about 1 to 20 hours. If desired, the thermosetting time can be shorter or longer.

In a specific example, the uncured phenolic resin threads are at room temperature for 0 to 5 hours in an aqueous mixed solution containing 0.1 to 30 percent by weight of an acidic catalyst, for example a mineral acid such as hydrochloric acid, sulfuric acid, or a Lewis acid, an organic Carboxylic acid, such as acetic acid or formic acid or a sulfonic acid, such as p-phenolsulfonic acid or p-toluenesulfonic acid and 0.5 to 35 percent by weight of an aldehyde, such as formaldehyde, at a ratio of thread to solution of 1: 5 to 1: 200 and immersed the solution is heated from room temperature to 50 to 150 ° C in the course of 0.05 to 10 hours. The solution is then kept at a temperature of 50 to 105 ^° C. for 2 to 20 hours to harden the threads. According to an alternative method, after the heating described above, the solution is kept at a temperature of 50 to 105 ^° C. for 0 to 2 hours to partially harden the threads, preferably to a degree of hardening of 0.5 to 3%, in particular 1 to 2% and then will

the threads are immersed at room temperature in an aqueous mixed solution which contains 0.2 to 15 percent by weight of a basic catalyst such as ammonia or sodium hydroxide or potassium hydroxide and 1 to 35 percent by weight of formaldehyde. Then the solution is increased to 70 to 95 ⁰ C in the course of about 1 hour and at this temperature for 0.5. held for up to 10 hours to harden the threads. In a further embodiment, the reaction is carried out at 50 to 105 ^° C. after heating in the above-mentioned hardening reaction for a maximum of 2 hours to partially harden the threads to the above-mentioned degree of hardening and then the threads are converted into a mixture or an aqueous mixture at room temperature Immersed mixed solution containing 0.2 to 15% by weight of the above basic catalyst or 0.1 to 30% by weight of the above acidic catalyst, 1 to 35% by weight of formaldehyde and 0.1 to 80% by weight of a solvent. The solution is then heated to 40 to 110 ° C. in the course of 0.2 to 2 hours and held at this temperature for 0.2 to 10 hours to harden the threads.

The solvents used for this purpose are, for example, alcohols such as methanol, ethanol or Isopropanol, ketones such as acetone or methyl ethyl ketone, ethers such as dioxane or tetrahydrofuran, polar Solvents such as dimethylformamide, dimethylacetamide or dimethyl sulfoxide or aromatic hydrocarbons such as benzene, toluene or xylene.

The term "degree of hardening" of the hardened threads, as used here, gives the percentage of Increase in the weight of the hardened threads, based on the original weight of the uncured threads.

The thread-like phenolic resins used as a substrate according to the invention for the radiation-shielding Phenolic resin fibers according to the invention can be cured to such an extent that you Degree of hardening after hardening treatment 5 to 30%, preferably 9 to 25%, and more preferably 11 to 20%. A phenolic resin thread, the degree of hardening of which is less than 5%, is unfavorable because the Damage to game properties during sulfonation treatment. which will be described below is large because of the infusibility of the thread is insufficient. On the other hand, if the degree of hardening exceeds 30%, the crosslink density becomes too high, so that only an unfavorable thread, whose bending properties and elongation are bad, can be obtained.

Furthermore, when performing the above-described spinning or hardening treatment, a active nitrogen containing compound of the formula

R ₁ YR,

\ Ii /

N — C — N
/ \

55

(I)

where Y is an oxygen atom, sulfur atom or a group NH and Ri, Rj. R3 and R * which could be the same or different, a hydrogen atom, a lower hydroxyalkyl group, for example a hydroxyalkyl or hydroxypropyl group or a lower alkoxyalkyl group, VOrZa ₁ SSWdSe MetiiGxätymethyK - Or ethoxymethyl group or Ri and Rj together are a lower one

Alkylene group, for example

-CH ₂ CH ₂ - or -CH ₂ CH ₂ CH ₂ -

can form, for example urea, thiourea, mono- or dimethylol derivatives of urea or thiourea or mono- or dimethyl or ethyl ethers of urea or thiourea, melamine, acrylamide, acrylthioamide, N-methylolated acrylamide, N-methylolated acrylthioamide, N-methylolacrylamide methyl ether. Dicyandiamide, triethylenetetramine, polyethylenimine or piperazine are introduced into the phenolic resin to obtain a phenolic resin fiber in which these compounds are bonded. A phenolic resin fiber which contains one of the above-listed compounds incorporated shows an improvement up to 50 to 70 ^° C. in terms of heat resistance. As a result, such fibers are valuable as raw materials for radiation-shielding fibers in which particular heat resistance is required.

The incorporation of compounds of formula (I) in the phenolic resins can be prepared by mixing the compound of formula (I) into the molten Polymers before spinning the polymer or by treating the filaments with a liquid that has the containing active nitrogen-containing compound at any desired stage during the curing of the melt-spun uncured filaments can be achieved.

This latter method can be accomplished by replacing at least a portion of the curing treatment of the phenolic resin filaments by the step of contacting the threads with a liquid which is the active Containing nitrogen-containing compound, carried out at a temperature from room temperature to 150 ° C will. This liquid can contain an aldehyde and / or a basic or acidic catalyst Contain the concentration to be specified. In general, the contact can be made by immersing the threads in the liquid bath containing the nitrogen-containing compound, or by passing through the Threads are run through the bath or by spraying or by vapor deposition.

In this embodiment of the invention, the uncured threads with a liquid which the contains nitrogen-containing compound, after the partial hardening thereof by hardening processes known per se be treated. On the other hand, the threads can first with the above liquid treated and then hardened by an ordinary method. Or the whole process The hardening can be achieved by treatment with the liquid which contains the active nitrogenous compound contains, be replaced. Furthermore, hardening treatment and treatment with the above described liquid are executed at the same time. However, it is with each of the foregoing Treatment process essential, the uncured thread with a treatment solution, which a Aldehyde or a compound containing a group derived from an aldehyde, for example a Methylol group. and preferably such active nitrogen-containing compounds as above, which contain a hydroxyalkyl group to treat. The purpose of this is to enable the response between the phenolic resin and the compound containing the active nitrogen is ensured.

609 684 313

To continue an undesirable dissolution of the uncured filaments in the early stages of their hardening To avoid it, it is advantageous to rub the threads with an aqueous treatment liquid or a treatment liquid to treat from organic solvents and water. When using this procedure it is recommended that the uncured Phenolic resin threads first with an aqueous treatment liquid or a treatment liquid are treated from organic solvents and water to partially harden the threads and that then the partially hardened threads continue to swell under more severe conditions Formation of hardened threads which are hardened even in their inner parts.

This method is explained below with reference to some specific embodiments of the mode of operation.

(1) The phenolic resin thread, after it has been partially hardened as described above (degree of hardening 0.1 to 3%) at room temperature in a combined solution of 0.1 to 25 percent by weight of an acidic or basic catalyst, 1 to 30 percent by weight of formaldehyde , 0.5 to 15 percent by weight urea or thiourea and 1 to 50 percent by weight of an alcohol such as methanol or ethanol or a ketone such as acetone or methyl ethyl ketone or an ether such as dioxane or tetrahydrofuran, whereupon the temperature of the solution rises to 50 to 90 ⁰ C for a period of 0.5 to 2 hours, at which temperature the reaction is continued for an additional 0.5 to 25 hours.

(ii) The uncured threads are first immersed in an aqueous solution or solution in organic solvent and water of a mixture of aldehyde and the compound containing the active nitrogen or the one lower hydroxyalkyl group and the active nitrogen at 0 to 40 ° C. for 0 to 12 hours containing compound is immersed, and the solution is heated for 0.05 to 10 hours in the presence of an acid catalyst at a temperature from room temperature to 50 to 105 ^° C. The solution is heated at this temperature for 0 to 2 hours to harden the threads The partially cured filaments are immersed in an organic solvent solution of a lower hydroxyalkyl group-containing compound containing the active nitrogen which is the same as or different from that above nitrogen-containing compound, or in an aqueous solution or e immersed in a solution in water and organic solvent of an aldehyde and allowed to stand for 0 to 2 hours in the presence of a basic or 5s acidic catalyst. The solution is then gradually heated from room temperature to 50 to 150 ^° C. over the course of 3 hours and kept at this temperature for 0 to 15 hours. This makes it possible to produce phenolic resin threads which contain bonds such as those of urea and which are not only heat-resistant and solvent-soluble, but also have excellent non-flammability and heat resistance. $ 5

Furthermore, the introduction of the compounds of the formula (I) can also be effected by immersing the phenolic resin fibers cured as described above in a liquid which contains the compounds of the formula (1), or by spraying the threads with such a liquid.

For example, the cured dipped Phenolhärz yarns in a solution containing compound containing the above-described active nitrogen and, generally at 45 to 150 ° C, preferably 60 to 105 ⁰ C, while for 0.5 to 10 hours. Then, the treated filaments are washed and dried so that the active nitrogen-containing compound is introduced into the interior of the filaments.

The melt-spun filaments can be added at any desired point in time before and / or after curing be stretched. The stretching often results in the achievement of even more favorable properties of the threads.

The stretching operation can be carried out either in one stage or in two or more stages and the Threads can be stretched either cold or hot. In the case of multi-stage stretching, the Cold and hot stretching can be combined if desired. The stretching ratio is also optional and is usually up to 2.5 times, based on the length of the unstretched thread.

The phenolic resin threads obtained in this way are then shaped in the following sulfonation stage of threads. Staple fibers, knitted or woven cloths or non-woven cloths or nonwovens fed.

Sulfonation

The sulfonation can be carried out by various methods and there is no particular limitation with regard to the method that can be used, provided that the sulfonic acid group (-SO ₃ H) either directly in the phenol nucleus of the novolak resin. which forms the phenolic resin fiber of the present invention or is introduced to the methylol group or phenolic hydroxyl groups connected to the phenolic ring.

For example, the sulfonic acid group can be added to the phenolic resin by treating the cured phenolic resin filaments with a sulfonating agent such as concentrated sulfuric acid. Oleum, chlorosulfonic acid, sulfur trioxide or sulfuryl chloride can be introduced. The conditions of sulfonation can vary within a wide range depending on such factors as the composition and degree of curing of the phenolic resin, the denier of the filament and the type of sulfonating agent employed. Typically, the sulfonation can be by immersion of the to be sulfonated phenolic resin yarns in a bath which contains one of the above-mentioned sulfonating agent at a temperature from 0 to 150 ⁰ C and preferably 10 to 120 ° C at a bath ratio, d. H. Weight ratio of thread to sulfonating agent, from 1:10 to 1: 100 and preferably 1:20 to 1:50 and then holding the threads in the bath for 1 to 10 hours and preferably 3 to 5 hours. However, in the case where chlorosulfonic acids are used as sulfonating agents, it is necessary, after the sulfonation, to convert the chlorosulfonyl group into the sulfonic acid group by hydrolysis.

In order to accelerate the sulfonation in this case, if necessary, the hardened PheaoSiarz threads can be subjected to a swelling treatment before the sulfonation with a solvent such as dioxane, acetone, Methyl ethyl ketone, benzene toluene, xylene dimethylformamide or dtaetfcyiacetatnid be subjected.

This swelling treatment, by immersing the cured phenolic resin yarns in a bath containing this swelling agent for about 1 to 5 hours at a temperature of 50 to 12O ⁰ C. In the case where the sulfonation of the cured phenolic resin threads is carried out, such as using concentrated sulfuric acid, this can be achieved in the following manner: The phenolic threads are immersed in an amount of 1 to 10 parts by weight | ₀ in a bath which contains 100 parts by weight of concentrated sulfuric acid, the treatment being carried out for 5 to 10 hours at a temperature of 80 to 150 ° C. to introduce the sulfonic acid groups into the phenolic core of the novolak resin of the threads. On the other hand, if the sulfonation is carried out with oleum, the sulfonation is possible in a similar manner by a treatment consisting in the immersion of the phenolic resin filaments during 1 to 10 hours, with a temperature of 0 to 8O ⁰ C instead of the temperature above is applied.

In the sulfonation of the cured phenolic resin filaments using the above sulfonating agents. For example, concentrated sulfuric acid, there are cases where discoloration of the threads takes place, what depends on the sulfonation conditions used. But if you wish, such a thing To avoid discoloration, sulfonation processes using aminosulfonic acids are beneficial are used.

As aminosulfonic acids, taurine is beneficial. N-alkylated taurine, such as N-methyl taurine or alkali salts such compounds, for example the sodium salt of taurine, the sodium salt of N-methyltaurine or the potassium salt of N-methyltaurine, can be used.

In the case of a hardened phenolic resin thread with a degree of hardening of up to 30%, as used according to the invention, the methylol group ( _{--CH 2} CH) is usually present in the amount of 3 to 20 mol percent on each phenolic nucleus. In the sulfonation process using the aminosulfonic acids, this methylol group reacts with the aminosulfonic acids and generally 0.5 to 1.5 milliequivalents / g-thread of sulfonic acid groups are introduced.

The sulfonation reaction, using an aminosultonic acid, is generally carried out by immersing the cured phenolic filaments in a bath containing the aminosulfonic acid in a concentration of preferably 5 to 80 percent by weight and more preferably 10 to 60 percent by weight either in water or an organic solvent such as includes methanol, ethanol, propanol, dioxane, dimethylformamide, dimethylacetamide or dimethyl sulfoxide or a solvent mixture of two or more of the foregoing solvents, at a temperature from 70 to 150 ^e C and preferably 80 to 130 ⁰ C at a bath ratio of 1: 10 to 1 : 100 and preferably 1:20 to 1:70 in which the filaments are held for 1 to 5 hours and preferably 2 to 4 hours in order to effect the sulfonation. If an organic solvent is used, it is advantageous to choose phenolic resin threads which are queued. As a result of the reaction between the amino groups and the methyl groups, it is possible to introduce the sulfonic acid groups without discoloration of the fibers or at least deterioration of the yarn properties. However, this sulphonation method generally has the disadvantage that the amount of sulfonic acid groups introduced becomes somewhat lower.

The sulfonation treatment in which aminosulfonic acids are used will be explained in more detail in the context of the following description for the case of the use of N-methyltaurine. The cured phenolic resin threads are added in an amount of 1 to 10 parts by weight to 100 parts by weight of a 70% aqueous N-methyltaurine solution and in the state immersed in the solution ^; Filaments during 1 to 5 hours at a temperature of 70 to 120 ⁰ C VorV held, thereby making it possible to introduce the sulfonic acid group in the filaments in an amount of usually 0.5 to 2.0 milliequivalents / g-thread. Alternatively, the hardened threads are by immersion in a solution of 30 percent by weight of taurine in dimethylformamide in a bath ratio of 1: immersed 100 during 3 to 5 hours at a temperature of 90 to 150 ⁰ C, whereby <.a is also possible to use the sulfonic acid group in in an amount usually from 0.8 to 1.6 miliequivalents / g-filament.

It is also possible in the case of this sulfonation to swell the phenolic resin threads with subject to a swelling agent prior to the sulfonation treatment.

Another effective method of introducing the sulfonic acid group is by introducing the Sulphonic acid group on the phenolic hydroxyl group of the phenolic resin, for example by an etherification reaction or use of oxysulfonic acids such as isethionic acid. In the same way are called oxysulfonic acids Other acids besides isethionic acid can be used, such as 3-hydroxy-1-propanesulphonic acid, 4-hydroxy-1-butanesulphonic acid or dehydrocyclysed products thereof.

This sulfonation reaction using these oxysulfonic acids can usually be carried out in the following manner. The cured phenolic resin threads to be sulfonated are dissolved in a sulfonation solution of the oxysulfonic acid either in water or in an organic solvent, preferably one or more classes of an organic solvent that swells the fibers, such as dioxane, dimethylformamide, dimethylacetamide or dimethyl sulfoxide, in a concentration of 20 to 80 percent by weight and preferably 30 to 60 percent by weight for 1 to 10 hours and preferably 2 to 8 hours at a temperature of 80 to 150 ⁰ C and preferably 100 to 130 ° C immersed. In this case, to accelerate the sulfonation reaction, a catalytic amount of an acid, for example p-toluenesulfonic acid, benzenesulfonic acids, zinc chloride, sulfuric acid or phosphoric acid, can be added to the bath at a rate of 0.5 to 5 percent by weight. Specifically, the introduction of the sulfonic acid groups can, for example, by adding 1 to 10 parts by weight of the threads to 100 parts by weight of a solution obtained by adding 3 percent by weight of p-thiolsuffonsane to a solution with 30 percent by weight of isethionic acid in dimethylacetamide and treating the threads by immersion therein for 1 to 5% Stranding can be achieved at a temperature of 1ΟΘ to 145 ° C. This gives phenolic resin threads in which the sulfonic acid groups are introduced in an amount of 1 to 2 milliequivalents / g-thread.
Regardless of which of the above methods is used

Introduction of the sulfonic acid group is applied is it if the sulfonated thread-like phenolic resin, which consists predominantly of a novolak resin, the Sulphonic acid groups in an amount of 0.1 to 4.0 milliequivalents / g-filament, preferably 0.5 to 3.0 Milliequivalents / g-filament, and more preferably 1.0 contains up to 2.0 milliequivalents / g-thread. If the amount of sulfonic acid groups introduced is less is than 0.1 milliequivalents / g, this is unfavorable because the The amount of bonded radiation shielding metal atoms then becomes low. On the other hand, if 4.0 Milliequivalents / g are exceeded, there is a tendency to greater damage to the fiber properties on.

"5

Introduction of the metal atoms of great radiation shielding capacity

The most important feature of the radiation-shielding phenolic resin fibers according to the invention resides in the fact that a metallic element with a capacity to shield radiation enters the fiber is introduced and is chemically bound in the ionic state in the novolak resin, which is in the hardened Phenolic resin thread is contained, which was obtained in the above manner.

As metallic elements with a large radiation shielding capacity those which can be present as cations in aqueous solution and can interrupt the passage of radiation are used and in general, metallic elements whose atomic number is large, and particularly those with an atomic number above 13, such as aluminum, chromium, manganese, iron, cobalt, Nickel, copper, zinc, silver, palladium, zircon, antimony, titanium, cadmium, barium or lead can be used. Of these, cadmium, barium and lead are particularly preferred. Of these three elements, lead becomes am most preferred

These metals can easily be incorporated into the hardened thread-like phenolic resin with the sulfonic acid groups, which was formed in the manner described above, by treating the polymer with a Solution containing the above metal ions can be introduced. Can also be used for relief of the ion exchange, the sulfonic acid groups introduced into the phenolic resin in the manner described above if necessary, in advance in the form of an alkali salt by treatment with a aqueous solution of an alkali compound, for example potassium hydroxide, are transferred.

The solutions containing metal ions with large radiation shielding capacity include the solutions of water-soluble salts such as the nitrates, carbonates, halides or hydroxides of the above metals, and examples thereof are lead nitrate, cadmium chloride, barium chloride, cadmium nitrate, barium nitrate, lead chloride, zirconium oxychloride, or copper chloride Bleach chloricL Although water is sufficient as a solvent, mixtures of water and organic solvents are also advantageously used. The organic solvents advantageously used in this case are those which are miscible with water and which also have the property of swelling the phenolic resin fibers and are examples Dimethylformamide, dimethyl acetamide. Dioxane or dimethyl sulfoxide.

The salts or hydroxides of the above metals can be present in the solution in ion concentrations of 0.05 to 5N and preferably 0.1 to 3N.

The treatment with the solution containing the above metal ions having a large radiation shielding capacity can be sufficiently carried out only by contacting the above solution with the phenolic resin filaments which have been sulfonated in the above manner. For example, this contacting operation can be carried out by methods such as immersing the sulfonated filaments in a bath containing the above solution, or by passing the filaments through such a bath, or by a process in which the solution is passed through a column packed with the filaments, or by Spraying the threads with the above solution can be effected. Room temperature is sufficient as the treatment temperature, and although there is no need to heat the atmosphere, it is possible to heat ^{the atmosphere to a temperature in the region of 40 to 70 ° C. if necessary.}

In this way, radiation-shielding threads are obtained, which the metal ions with a large radiation shielding capacity in the amount of 0.1 to 3.5 milliequivalents / g-filament and preferably 0.5 to 3 milliequivalents / g-thread contain obtained.

Finished product made from phenolic resin fibers

The phenolic resin fibers produced in the manner described above according to the invention, which therein disperses chemically bound metal ions with a large capacity to shield radiation have excellent shielding effects against all types of radiation. Furthermore are these fibers also in such properties as heat resistance, yarn properties, in particular Flexibility, flame resistance and anti-melting properties are outstanding. Keep drawing the fibers according to the invention are also characterized by this. that the damage to these properties is small. even if the fibers are exposed to radiation. For example, show the phenolic resin fibers according to the invention Shielding effects against a very wide range of j9 rays, such as

²⁸ Mg, 3JP, 35S. sea, «ca," Ca. «Se,« Se, «Se,» Mn,
⁵⁹ Fe, 5 »Co,« »Co," Ni, "Ni," Cu, ^w Zn, ⁵⁹ Zn, ⁷² Zn, ⁷⁹ Sc, ⁸⁸ Kr, ⁹⁰ Sr, "Zr, '"3Ru,' »Pd, ¹¹⁵ In. " ¹ Sn, ²⁰³ Hg and
²²⁵ Ra,

not to mention the / 3 rays of low energy below 1 MeV, such as. B. ³ H and ¹⁴ C. In addition, they also show satisfactory shielding effects against rays of low energy.

Usefulness

The radiation-shielding phenolic resin fibers according to the invention can be used directly in the form of filaments, multifilaments or strands, but can also be used in the form of staple fibers cut into desired lengths . In addition, they can be used in spun yarns either all or in admixture with known threads or fibers, or in the form of twisted yarns. They can also be processed into various thread-like structures, such as knitted or woven cloths, non-woven cloths, hearts or mats, both alone and in admixture with known threads.

Therefore, the phenolic resin fibers according to the invention can be used in such forms for various purposes such as clothing, filters, protective strips, interior lining materials, Radiation shielding cushions and similar be used.

The following examples explain the invention in detail. In these examples, all parts are and Percentages based on weight.

example 1

1410 parts of phenol, 1180 g of a 37% strength aqueous formaldehyde solution and 20 parts of oxalic acid were added 95 ° C heated with stirring and held at this temperature for 3 hours. The reaction was through Aborted addition of a large amount of cold water.

The obtained phenolic resin was dissolved in methanol and subjected to reduced pressure to evaporate unreacted phenol, formaldehyde, methanol and water are heated, with a thermally fusible Novolak resin having a numerical average molecular weight of 820 was obtained.

500 parts of the novolak resin obtained was roughly pulverized, dried sufficiently, and then packed into a 1 liter stainless steel melter set up for external heating. the The interior of the facility was purged with nitrogen gas, and then the novolak resin was added Melted at 160 ° C. The molten novolak resin was poured from the bottom of the melter in a Speed of 3 g / min, through a nozzle with 18 holes each with a diameter of 2.5 mm, the was heated to 160 ° C, extruded. The filaments obtained were spun on spindles at a spinning speed of 1050 m / min, wound up by means of a 1.5 m winch attached directly below the nozzle. The threads were cut on the spindles and separated from the spindles in the form of a strand.

The resulting uncured novolak fibers were in an aqueous mixed solution with at room temperature

Table I.

a content of 18 percent by weight formaldehyde and 18 percent by weight hydrochloric acid immersed, wherein the ratio of fibers to solution was kept at 1: 100. The solution gradually rose to 95 ° C

heated over 2 hours and held at 95 ° C for 6 hours, thereby hardening phenolic resin fibers obtained with a degree of hardening of 174% became. The fibers were washed with water, dried and spun in the usual manner and

ίο woven and received a woven cloth. The woven cloth obtained was pale yellow in color and weighed 30 mg / cm ² .

The cloth was immersed in 25% fuming sulfuric acid, the ratio of cloth to Sulfuric acid was kept at 1:50 and the reaction at 50 ° C for 3 hours with stirring left. The woven cloth was removed, washed with water and immersed in 2N Na2SO4, keeping the wipe to liquid ratio at 1: 100. It was left to stand overnight and then removed the cloth and washed it with water. The cloth had a sulfonic acid group content of 2.0 milliequivalents / g.

The cloth was then immersed in a 10% strength aqueous solution of lead nitrate at 40 ° C. for 5 hours to bind the lead ions. The amount of bound lead was 0.8 millimoles / g. The cloth was dark brown in color and weighed 50 mg / cm ² .

A ^ radiation source of ⁹⁰ Sr was placed at the bottom of a cylinder with an inner diameter of 4 cm. A sheet structure consisting of two sheets of the above lead-containing cloth was attached at a point 10 cm from the ^ radiation source. The radioactive rays which passed through the cloth were measured with a Geiger counter, and the transmittance of the radioactive rays was determined. Furthermore, the permeability of a layer structure of 4 cloths and a layer structure of 6 cloths was determined in the same way. The results are summarized in Table I.

Cloths) Weight (mg / cm ² )
Permeability (%) Layer structure
out
2 cloths Layer structure
out
4 wipes Layer structure
out
e cloths According to the invention game 2 Weight (mg / cm ² )
Permeability (%) 100
29.1 200
14.3 300
6.2 Comparison (untreated 60
66.3 120
50.2 180
41.1 at Water washed and dried
mil 40 / n ophunHpnpm urea and and phenolic fibers
a hardship

The novolak threads produced according to Example 1 were only hardened on their peripheral parts with an aqueous mixed solution of hydrochloric acid and formaldehyde. The cured novolak threads were in a treatment liquid wedge, which by adding 5 parts of urea to 100 parts of a mixed liquid of methanol / hydrochloric acid (35.5%) / formaldehyde (37% aqueous solution) in a volume ratio of 3: 1: 1 was made, immersed, keeping the ratio of filaments to liquid at 1: 100. The treatment liquid was heated from 4O ⁰ C to 65 ⁰ C over 30 minutes and then the threads at 65 ° C for 4 hours iimoi «<ipi7i were. The threads were taken off with a degree of 19%.

The phenolic resin filaments obtained were immersed in a concentrated sulfuric acid solution having a content of 20% dimethylacetamide at room temperature, wherein the ratio of fibers to solution at 1: was held 50, and then leave the reaction at 8O ⁰ C for a certain period of time. The filaments were then removed, washed thoroughly with water, and converted to the sodium form using 1N sodium hydroxide solution. The sulfonic acid group content of the threads was determined.

10 parts of the above containing sulfonic acid groups Fibers were treated with 1000 parts of an aqueous

Solution containing 1000 ppm lead nitrate in a packed column with a flow rate of 0.1 BV / Miri. treated, whereby the sulfonic acid groups were converted into lead sulfonate groups. The amount - of bound lead was determined by quantifying Pb ⁺⁺ in the treatment water

The threads were further washed thoroughly with water and ^{dried at a reduced pressure at 80 °} C. The tensile strength of the threads was then measured. The threads became staple fibers of 5 cm

Table!!

Cut to length, and according to the usual method, a non-woven fabric (non-woven fabric) having a unit weight of 100 g / m ^{2 was} prepared

The nonwoven cloth was mm at 15O ⁰ C at a pressure of 40 kg / cm ² to form a sheet having a thickness of 0.6 hot pressed Six such sheets were layered and this layered structure the passage of / ^ - rays of ⁹⁰ Sr exposed; the permeability to radioactive rays was determined. The results are shown in Table II.

sample reaction time Content of a
guided Amount of
bound Gam quality
strength strain Through Sulfonic acid groups lead nonchalance (Hours) (Milliequivalents / g) (Millimoles / g) (g / d) (%) (%) comparison 0.2 0.04 0.02 1.8 59 59.1 according to the invention 0.5 0.12 0.05 1.8 55 41.1 according to the invention 1 0.55 0.25 1.6 52 34.2 according to the invention 1.5 1.11 0.55 1.4 47 27.3 according to the invention 2 1.78 0.82 1.2 45 21.0 according to the invention 5 2.79 1.27 0.95 30th 15.3 according to the invention 10 3.80 1.55 0.60 21 11.2 comparison 15th 4.10 1.77 0.41 14th 8.5

It follows from the values in Table II that the The content of introduced sulfonic acid groups is favorably not less than 0.1 milliequivalents / g and that. if the value exceeds 4 milliequivalents / g, the shielding effectiveness is satisfactory, however, the quality of the threads is considerably deteriorated.

Example 3

The novolak threads produced according to Example 1 were immersed in an aqueous mixed solution containing 15 percent by weight of hydrochloric acid and 16 percent by weight of formalin at 30.degree. C., the ratio of threads to solution being kept at 1:50. The solution was gradually ^{heated to 90 °} C. and the threads were then removed and washed with cold water.

The treated novolak threads, which were only hardened on the outer surface layer, were in a mixed solution of 90 parts of a 28% strength aqueous solution of ammonia and a 37% strength aqueous solution Formaldehyde solution immersed, keeping the ratio of threads to solution at 1: 100. the Solution was heated to 95 ° C over 30 minutes and then the filaments were at 95 ° C for 2 Cured hours and obtained cured phenolic resin threads with a degree of cure of 10.5%.

The cured threads were immersed in a 70% strength aqueous solution of N-methyltaurine, the ratio of threads to solution being kept at 1:50 and allowed to react at RO ⁰ C for 3 hours to introduce the sulfonic acid groups. The threads were then immersed in an aqueous NaOH solution for f0 hours with stirring in order to convert the sulfonic acid groups into sodium sulfonate groups. The sulfonic acid group content was also determined and was 1.1 milliequivalents / g.

The threads were then immersed in an aqueous solution which contained cadmium chloride in a concentration of 1000 ppm at 25 ^° C. for 15 hours in order to introduce cadmium ions into the phenolic resin threads. The treated filaments were pale yellow in color.

A non-woven fabric having a unit weight of 100 g / m ² was produced in the same manner as in Example 2. The transmittance of radioactive rays through this nonwoven cloth was determined in the same manner as in Example 1, except that the radiation of ¹⁴ C was used. The degree of shielding was at least 95%.

On the other hand, a non-woven cloth was made from untreated threads in the same way the level of shielding was only 55%.

B e i s ρ i e! 4th

A fiber material with a fiber length of not more than 2 microns, which is produced by blowing the in Example 1 molten novolak resin produced was produced using an air nozzle, was in an aqueous mixed solution with a content of 18% hydrochloric acid and 13% formaldehyde Immersed at room temperature for 12 hours. The solution was heated to 95 ° C over 6 hours heated and the fiber material was further 6 hours to form fiber material with a degree of cure hardened by 16.5%. The material treated in this way was in an aqueous solution with ein.em Resole content of 2% and then dispersed into a paper-like sheet according to conventional sheet-forming methods deformable

Using this paper-like sheet, the following three samples were prepared.

(A) The paper-like sheet was treated with fuming sulfuric acid at 40 ° C for 10 hours, washed with water and then in 1N NaCl solution

immersed, keeping the ratio of sheet to liquid at 1: 300, to give sodium sulfonate groups to be introduced into the phenolic resin fibers (content of sulfonic acid groups 23 milliequivalents / g). Then the sheet was immersed in a 10% aqueous solution of lead nitrate at room temperature for 10 hours immersed, then washed thoroughly with water so that the lead ions were bound. The amount bound lead was 18.6 g / 100 g.

(B) The paper-like sheet was immersed in a 15% aqueous solution of lead nitrate for 5 hours immersed and then weakly squeezed with a mangle The amount of lead adhered (calculated from the amount of lead nitrate taken up was 19.6 g / 100 g.

(C) A lead powder passed through a 100-mesh sieve was dispersed in an amount of 30% in a phenolic resin adhesive. The resulting lead-containing adhesive was uniformly coated on the paper-like sheet so that the lead content was 20% and then heat treated at 80 ⁰ C for 5 Soinden, so that the adhesive is cured and at the same time, the lead was fixed.

The shielding effect of each of these samples was determined according to the procedure of Example 1 using the ^ radiation of ⁹⁰ Sr

Then the samples were each treated with warm water of 80 ° C for 2 hours and the Shielding effect measured again in the same way. The results are given in Table III.

Table III

Sample amount of lead Before washing After washing

Density Permeability Density Permeability

(g / 100 g sample) (mg / cm *) (%) (mg / cm ³ ) ( ⁰ A)

Blank sample (untreated)

It can be seen from the values in Table III that the phenolic resin materials according to the invention have one high jS radiation shielding effect and good Resistance to washing operations compared to those produced by conventional processes, own.

When the above paper-like sheets are actually used as interior decoration material, for example are used, the flexural strength thereof is an important factor during the manufacturing process and during end use. The sample A had a very good flexural strength in comparison to comparative sample C. If the durability by repeatedly bending the above samples in a Bending angle of 60 ° was determined, it was found that the sample C broke after 10 flexions, while none Change was observed in Sample A even when it was flexed 10000 times.

Example 5

The novolak resin obtained in Example 1 was molded into the shape of spheres having a diameter of 5 mm. 20 parts of nylon-12 (having a relative viscosity of 1.80, determined with a 0.5% m-cresol solution at 30 ° C.) in the form of chips and 80 parts of the above novolak resin were completely mixed in a rotary dryer and then a melt spinning apparatus maintained ^{at 200 ° C. with}

18.6 71 31.5 71 31.2 19.0 68 45.2 42 71.9 20.0 77 47.5 72 51.3 0.0 42 73.1 42 72.8

fed to a nozzle diameter of 20 mm, whereupon at a spinning speed of 800 m / min, under Formation of threads was spun (50d / 18f). the The spinnability of the mixture was better than that of the novolak resin alone.

The filaments obtained were cut into staple fibers about 5 cm long and kept at room temperature immersed in an aqueous mixed solution of 18% hydrochloric acid and 9% formaldehyde. The solution was heated to 90 ° C for 3 hours and then the threads were in this solution by continuing the Reaction cured for 5 hours. The cured filaments had a degree of cure of 12.8%.

A woven cloth weighing 40 mg / cm ² was produced in the same manner as in Example 1. The woven cloth was left to react in 25% strength fuming sulfuric acid at 40 ^° C. for 2 hours. The treated wipe contained 1.2 milliequivalents / g of sulfonic acid. The cloth was then immersed in 1/2 N NaOH to convert it to the sodium sulfonate form. The cloth was then immersed in a 5% strength aqueous solution of lead nitrate at room temperature to bind the lead ions. The amount of bound lead was 0.5 millimoles / g and the weight of the cloth was 49 mg / cm ² .

Three sheets of the cloth were placed one on top of the other and the transmission for 0 rays in the same Manner as determined in Example 1 which was 28%.

Claims (5)

Patent claims: 1. Radiation-shielding fibers made of phenolic resins, characterized in that the fibers consist of a polymer containing metal atoms with a high radiation protection capacity, 100 to 70 percent by weight of a cured novolak resin with a content of 0.1 to 4.0 m equivalent / g-fiber of a sulfonic acid, ₀ group and with a ^{degree of hardness of 5 to 30 c} > ij, and 0 to 30 percent by weight. a.from a fiber-forming: thermoplastic synthetic polymer, the metal atoms being chemically bonded to the sulfonic acid group of the novolak resin in an amount of 0.1 to 3.5 m-equivalent / g-fiber in the ionic state. 2. Fiber according to claim 1, characterized in that it is a metal atom with a large radiation shielding capacity Contains cadmium, lead and / or barium. 3. Fiber according to claim 1 or 2, characterized in that it consists of a mixture of the Novolak resin with polyamide, polyester, polyester ether, polyolefin and / or polyurethane. 4. Process for the production of a radiation shielding Fiber according to claim 1, characterized in that one (a) Fase η from a polymer, 100 to 70 percent by weight of a novolak resin and from 0 to 30 weight percent of a fiber-forming thermoplastic synthetic Composed of polymers, a hardening treatment with a hardener to a degree of hardening of 5 to 30% subject, (b) the cured fibers obtained are sulfonated and (C) the cured sulfonic acid group-containing polymer fibers obtained, if necessary for Treatment of the sulfonic acid groups in the form of alkali salts and then treated the fibers containing a metal ion with a great radiation protection capacity Treated solution to introduce the metal atoms into the polymer. 5. Use of the radiation-shielding fibers made of phenolic resins according to one of the claims 1 to 3 for the production of yarns, knitted goods, woven goods, nonwovens, felts or mats. 50