RU2776174C1 - Butadiene-nitrile latex, latex composition for immersion dipping, dipped product - Google Patents

Abstract

FIELD: protective means.

SUBSTANCE: present invention relates to latex used for the manufacture of products by immersion dipping, in particular for the production of latex gloves for industrial and medical purposes, as well as to a composition for immersion dipping based on butadiene-nitrile latex, a dipped product and a glove prepared on the basis of a latex composition. The mentioned latex includes structural units formed from at least one monomer, which is a conjugated diene, at least one ethylene unsaturated monomer containing a nitrile group, and at least one monomer, which is an unsaturated carboxylic acid. The value of the latex solubility index (A), calculated by the formula A =100*p*S/(M_n+M_w), ranges from 0.5 to 2,2, wt. %, *nm*mol*g^-1, where p is the solubility of the polymer in methyl ethyl ketone (wt. %), S is the size of latex particles (nm), M_n is the average molecular weight of the tetrahydrofuran–soluble part of butadiene-nitrile latex (g/mol), M_w is the average molecular weight of the tetrahydrofuran-soluble part of butadiene-nitrile latex (g/mol). The polydispersity value of the latex polymer M_w/M_n ranges from 2.0 to 5.0.

EFFECT: resulting latex has the elasticity of raw gel of at least 1000%, sufficient to ensure the necessary physical and mechanical properties of the vulcanized film, while latex has high resistance to mechanical influences, limited resistance to the action of electrolytes, as well as the necessary dynamic viscosity.

13 cl, 6 tbl, 13 ex

Description

The present invention relates to nitrile butadiene latex, preferably carboxylated nitrile butadiene latex, used for the manufacture of products by dipping, in particular for the production of latex gloves for industrial and medical purposes.

The present invention also relates to a nitrile butadiene latex dip dipping composition and dipped products made using such a composition.

The level of technology.

The dipping dipping process involves dipping a ceramic or other form into a latex composition having the desired shape of the final product. Among the methods of submerged dipping, the production of products by the ionic deposition method is distinguished, during which the mold is sequentially placed in a bath with a salt solution, and then in latex, followed by coagulation of the latex globules under the action of the cations of the salt mentioned above. This method is used, for example, in the manufacture of medical gloves. Gloves for technical purposes can be fabric or baseless. Fabric gloves can be immersed either directly in latex without pre-immersion in coagulant, or with pre-immersion.

The properties of products obtained by immersion dipping are largely influenced by the nature of the latex. Dipped products can be made from nitrile butadiene latex, but in cases where it is necessary to provide higher physical and mechanical properties (strength, elasticity, etc.), carboxylated nitrile butadiene latexes are used.

Medical gloves are usually made from natural or carboxylated nitrile butadiene latex. At the same time, in the modern world, natural latex gloves are produced less and less: they can cause allergies, and the availability of natural latex depends on the yield of hevea plantations. Gloves based on carboxylated butadiene-nitrile latex have physical and mechanical characteristics close to natural latex, but do not have the above disadvantages. Besides, such gloves possess the increased maslobenzostoykost.

A number of requirements apply to latexes used in dip dipping. So they should have a high aggregative stability, but at the same time it is easy to coagulate under the action of 2-3 valence electrolytes with the formation of a strong and elastic film. In addition, dip dipped latex films, in particular ionic deposition, are required to maintain an uncolored, clear film and be free from tackiness. In particular, a glove for medical use made from nitrile butadiene latex should be colorless, thin, durable, elastic, provide tactile sensitivity, have no residual stickiness and external defects in the form of sagging, bubbles and cracks.

One of the ways to obtain latexes is emulsion copolymerization, which is carried out in a complex multicomponent microheterogeneous system, the management and control of which is difficult to implement in practice. In connection with this circumstance, it is of particular importance to identify the degree of influence on the achievement of the required properties of the resulting product (composition of the monomeric phase, emulsifiers, molecular weight regulators, initiators, electrolytes, etc.), individual reagents, as well as groups of reagents for various purposes, their quantity and conditions of introduction into the system. This is important, since the factors mentioned can have a multidirectional effect on the specific characteristics for use in the production of dipped products, the characteristics of the obtained nitrile rubber latexes and the films formed on their basis.

Patent EP2457933 describes an adhesive composition for the manufacture of belts containing a latex of highly saturated nitrile rubber, providing high oil resistance and good adhesive properties, while one of the characteristics of the latex indicates the content of the insoluble fraction in tetrahydrofuran, according to the invention, it ranges from 30 to 70 wt. %. The inventors claim that if the content of the tetrahydrofuran-insoluble fraction is too low, when the adhesive layer is formed by curing the composition, the resulting adhesive layer deteriorates in oil resistance, and the composite obtained using the adhesive composition also exhibits poor oil resistance. If the content of the tetrahydrofuran-insoluble fraction is too high, it becomes impossible to form an adhesive layer with a uniform thickness, that is, when used as an adhesive composition, sometimes a film may not be formed. The average particle size of the latex is preferably 0.01 to 0.5 µm, and the solids content of the latex is preferably not more than 50% by weight.

However, the patent does not disclose the effect of these indicators and molecular weight characteristics on the physical and mechanical properties, as well as the properties of products made from latex by the dipping method.

From patent EP3124512, high-saturated nitrile rubber latex and adhesive compositions based on it are known, used in the manufacture of belts. Said latex, inter alia, is characterized by a chloroform-soluble polymer content with a weight average molecular weight in the range of 100,000 or less. According to the present invention, if the weight average molecular weight of the chloroform-soluble substances is too high, the resulting adhesive layer eventually deteriorates in elasticity. The weight average molecular weight of substances soluble in chloroform is determined by dissolving a highly saturated nitrile rubber in chloroform and measuring the content of soluble substances in the resulting solution using gel permeation chromatography (GPC). At the same time, the molecular weight distribution (Mw/Mn) of substances soluble in chloroform is not limited, but preferably ranges from 2 to 100.

The patent does not disclose the influence of solubility values in other solvents, in particular, methyl ethyl ketone, on the properties of latexes, as well as the influence of other indicators, including the particle size of the latex and its molecular weight characteristics, on the properties of products produced by the dipping method.

From US10000868 a highly saturated nitrile rubber latex for use in the manufacture of belts is known, which, among other features, is characterized by a THF-insoluble fraction content of 30% by weight or more. More specifically, the content of the tetrahydrofuran insoluble fraction is preferably 35 to 95 wt.%, more preferably 45 to 90 wt.%, and most preferably 50 to 80 wt.%. The present inventors point out that too little THF-insoluble fraction will adversely affect the oil resistance of the coatings. The average particle size of the latex is preferably 0.01 to 0.5 µm, and the solids content of the latex is preferably not more than 50 mass%.

The patent does not disclose the effect of these indicators, as well as molecular weight characteristics on the physical and mechanical properties, as well as the properties of products made from latex by the immersion dipping method.

US10907002 describes a copolymer latex of a conjugated diene, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid used for the manufacture of industrial gloves, wherein said latex has an average particle size of the copolymer from 60 to 300 nm, the content of substances insoluble in methyl ethyl ketone is not more than 70 wt.%, and also has a certain degree of swelling of the dry latex film in methyl ethyl ketone. According to the authors of this invention, a certain content of insoluble substances and a certain degree of swelling of the film contribute to the prevention of cracks in the rubber layer.

The patent does not disclose the requirements for molecular weight characteristics that provide the necessary physical and mechanical properties of materials for the production of products, in particular, medical gloves made from latex by the dipping method.

JPH09316131 describes a copolymer latex used to make coating compositions for paper. Said latex based on an aliphatic conjugated diene, an unsaturated acid monomer, and another copolymerizable monomer satisfies the following conditions:

XY/Z > 28000-8*(X-70)*2,

where X is the gel content (wt.%), Y is the weight average molecular weight of the component soluble in tetrahydrofuran, and Z is the average particle size of the latex (nm). Said latex provides an excellent balance between adhesive strength and blister resistance.

The application discloses the use of an index linking various characteristics of the polymer and its use in the production of coating compositions for paper, but it does not disclose the requirements for characteristics that ensure the use of the claimed latexes for the manufacture of products produced by the dipping method.

Thus, the prior art reveals the influence of individual factors on the properties of nitrile-butadiene latexes for various purposes, but there are no sources offering an integrated approach to the formation of requirements for nitrile-butadiene latex for a specific use - the manufacture of products by the dipping method. For a specialist, it is obvious that this problem cannot be skillfully solved by a simple process optimization, therefore, it can be argued that the problem of obtaining butadiene-nitrile carboxylated latexes that meets the necessary requirements for properties that ensure their effective use for the manufacture of products is still relevant. produced by the dipping method.

The problem to which the present invention is directed is to provide nitrile-butadiene carboxylated latexes and compositions based on them, having a set of properties necessary for use as starting materials for the manufacture of products by dipping, in particular, latex gloves for industrial and medical purposes. .

The authors of the present invention unexpectedly found that the achievement of the specified technical result occurs under conditions when a latex is obtained that has such a complex of specific properties that the numerical value of the indicator determined on their basis should be in a certain range of values.

Brief description of the invention

The object of the present invention is a latex intended for the manufacture of products by dipping, including structural units formed from at least one monomer, which is a conjugated diene, at least one ethylenically unsaturated monomer containing a nitrile group, and at least , one monomer, which is an unsaturated carboxylic acid,

in which the value of the solubility index (A), calculated by the formula

A \u003d 100 * p * S / (M _n + M _w ),

is from 0.5 to 22 wt.%*nm*mol*g- ¹ , preferably from 1.0 to 15 wt.%*nm*mol*g- ¹ , more preferably from 1.0 to 10 wt.%* nm * mol * g ^-1 ,

where p is the solubility of the polymer in methyl ethyl ketone (wt.%), S is the particle size of the latex (nm), M _n is the number average molecular weight of the tetrahydrofuran-soluble part of butadiene-nitrile latex (g/mol), M _w is the weight average molecular weight of the soluble in tetrahydrofuran tetrahydrofuran parts of butadiene-nitrile latex (g/mol), while the polydispersity value of the latex polymer M _w /M _n is from 2.0 to 5.0, preferably

2.0 to 4.0, more preferably 2.0 to 3.5.

Another aspect of the present invention is a dipping composition comprising a latex of the invention and at least one curing agent.

Another object of the present invention is a composition for the production of products by dipping method, consisting of 96-97 wt.% in terms of dry matter of the latex according to the invention, 3.0-3.6 wt.%, at least one vulcanizing agent, optionally 0.2-0.3 wt.% salt of fatty alcohol sulfoesters and 0.1-0.2 wt.% antioxidant based on the total dry matter weight of the composition of 100%.

Another object of the present invention is a latex-based dipped product or composition according to the invention, in particular, the product is a glove.

Another object of the present invention is the use of the latex according to the invention for the manufacture of dipped products, in particular gloves.

Detailed description of the invention

Within the framework of the present invention, a latex for the manufacture of products by dipping is provided, comprising structural units formed from at least one monomer, which is a conjugated diene, at least one ethylenically unsaturated monomer containing a nitrile group, and at least one monomer, which is an unsaturated carboxylic acid,

in which the value of the solubility index (A), calculated by the formula

A \u003d 100 * p * S / (M _n + M _w ),

is from 0.5 to 22 wt.% * nm * mol * g - ¹ ,

where p is the solubility of the polymer in methyl ethyl ketone (wt.%), S is the particle size of the latex (nm), M _n is the number average molecular weight of the tetrahydrofuran-soluble part of butadiene-nitrile latex (g/mol), M _w is the weight average molecular weight of the soluble in tetrahydrofuran tetrahydrofuran parts of butadiene-nitrile latex (g/mol),

while the value of the polydispersity of the latex polymer M _w /M _n is from 2.0 to 5.0.

The latex polymer in the context of the present invention is a product of the copolymerization of monomers, purified from the components of the reaction mixture, isolated from the latex.

The monomer mixture in the context of the present invention is the total amount of all monomers used to obtain the latex.

The technical result of the invention is to obtain a latex having a raw gel elasticity of at least 1000%, sufficient to provide the necessary physical and mechanical properties of the vulcanized film, while the latex has a high resistance to mechanical stress (no coagulum), limited resistance to electrolytes, as well as the necessary dynamic viscosity (more than 30 centipoise), which allow us to consider this latex as an ideal material for the manufacture of products by dipping. Films made from such latex do not have defects (sagging, perforations, cracks), they are distinguished by high values of physical and mechanical parameters: during combined (salt and sulfur) vulcanization, the strength of latex films is at least 30 MPa in combination with a relative elongation of at least 500% ; the resulting films are thin, strong and transparent.

The elasticity of the raw latex polymer gel is a particularly important characteristic that determines the quality of latex films formed during the dip dipping process, in particular, ionic deposition, which demonstrates, on the one hand, how effectively the coalescence (interpenetration) of latex globules took place during the dip dipping process, that is the presence of defects in the film, and on the other hand, according to the elasticity of the raw gel, one can judge the relative elongation of the vulcanized latex film. To achieve ASTM D 6319 vulcanized film elongation (at least 500% elongation), the green gel elasticity must be at least 1000%. In turn, the elasticity of the raw gel depends on the conditions of the emulsion copolymerization process in the preparation of butadiene-nitrile latex.

In the context of the present invention, the value of the solubility index A should be in the range of 0.5-22, preferably in the range of 1.0-15, most preferably in the range of 1.0-10. It is noted that when the solubility index A is outside the specified range, vulcanized latex films do not provide the level of physical and mechanical properties required by ASTM D 6319.

The solubility index is calculated based on the solubility of the polymer in methyl ethyl ketone (MEK), the particle size of the latex, the molecular weight characteristics of the polymer, and each of these indicators also affects the properties of the latex and products based on it.

The solubility of a nitrile butadiene polymer in methyl ethyl ketone (MEK) is an indicator of the crosslinking of the polymer, that is, the number of crosslinks formed: the higher the solubility, the fewer crosslinks and the less crosslinked the polymer is.

Nitrile butadiene polymer with high MEK solubility and low crosslinking has high elastic properties. Films made of such a polymer have high physical and mechanical properties, in particular, high strength and elasticity, as well as a low modulus at 500% elongation. A glove made using this latex provides a comfortable tactile sensation when worn. However, a polymer with high solubility in MEK is characterized by a high rate of syneresis (spontaneous compaction of the latex gel structure with the release of serum), which, in turn, can lead to defects in the polymer film, its shrinkage and a decrease in its physical and mechanical properties.

The nitrile butadiene polymer with low MEK solubility and high crosslinking, on the contrary, is characterized by slower syneresis, which can lead to an improvement in the structure of the formed latex film. However, the high cross-linking of the polymer causes its reduced elasticity, as well as the deterioration of the quality of the formed films - a decrease in their strength and elasticity and an increase in the modulus at 500% elongation, leading to a decrease in the comfort of tactile sensations when working with gloves. In addition, when forming films from a polymer with low solubility, there is a risk of cracking, and in extreme cases, films may not form at all.

Preferred MEK solubility values within the scope of the present invention are 30-100 wt%, more preferred 35-80 wt%, most preferred 40-70 wt%.

The particle size of the latex can be in a very wide range. An increase in particle size leads to a drop in dynamic viscosity, a decrease in the transparency of the latex film, and a decrease in particle size leads to an increase in viscosity and a decrease in its resistance to mechanical stress, as well as large losses of the polymer due to the formation of a surface film. In addition, the particle size of the latex affects the nature of the film formation, i.e. on the uniformity of the latex film and the presence of defects in it. In turn, the size of latex particles is influenced by the nature and dosage of the emulsifier, initiator, the ratio of the monomeric and aqueous phases, and many other factors. Within the scope of the present invention, the preferred latex particle size range is from 70 to 160 nm, more preferably from 70 to 140 nm, most preferably from 70 to 120 nm.

The values of the molecular weights of the polymer, in particular, weight average - M _w and number average - M _n are also important to achieve the technical result in accordance with the present invention. In general, an increase in the values of M _w and M _n leads to an improvement in the strength properties of the latex film, and a decrease in M _w and M _n leads to a decrease in strength while maintaining the elasticity of products from a latex film with a low thickness and low mass, as well as an increase in the values of moduli at elongation of 300% and 500%, which worsens the comfort of tactile sensations when working with gloves obtained by the method of submersible dipping.

Within the scope of the present invention, the preferred ranges are: M_w- from 50000 - 250000, Mn - from 25000 - 80000, more preferred: M_w-65000-230000, M_n– 30000 -75000, most preferred: M_w 80000 - 200000 M_n-35000 -70000.

In accordance with the present invention, the polydispersity value of the latex M _w /M _n is from 2.0 to 5.0, preferably the polydispersity value is from 2.0 to 4.0, most preferably from 2.0 to 3.5.

A polydispersity value below 2.0 leads to a deterioration in the elastic properties of the polymer and is not typical for elastomers obtained by emulsion polymerization. With a polydispersity value above 5.0, an increase in modulus occurs at 300% and 500% stretch, which reduces the comfort of the glove during use.

Nitrile-butadiene latexes are aqueous dispersions of copolymers of conjugated dienes and ethylenically unsaturated monomers containing a nitrile group, such as acrylic acid nitrile (NAC), obtained by emulsion polymerization. In addition, butadiene-nitrile latexes include other monomers.

Conjugated dienes from which latexes are derived may include 1,3-butadiene, 2-chloro-1,3-butadiene and 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1, 3-pentadiene, 2-methyl-3-ethyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 1,3-hexadiene, 2- methyl-1,3-hexadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene, 3-butyl-1,3-octadiene, 3,4-dimethyl-1,3- hexadiene, 4,5-diethyl-1,3-octadiene, phenyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2,3-di-n-propyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene.

Preferred conjugated dienes are 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3-pentadiene.

The most preferred conjugated diene is 1,3-butadiene.

The amount of the monomer, which is a conjugated diene, in the butadiene-nitrile carboxylated latex depends on the further scope of the latex and can be anything. To produce latex for dip dipped gloves, typically the amount of conjugated diene monomer added is in the range of 50 wt. hours to 85 wt.h, preferably from 60 to 75 wt.h., most preferably from 63 to 70 wt.h. per 100 wt. parts of the monomer mixture.

Acrylic acid nitrile is used as a comonomer for the production of latex, but other ethylenically unsaturated monomers containing a nitrile group can also be used, the presence of which provides a low solubility of the polymer in non-polar solvents such as liquid hydrocarbons and petroleum oils. It is also known that the nitrile-containing monomer imparts the necessary strength properties to the latex film.

As ethylenically unsaturated monomers containing a nitrile group, acrylonitrile, methacrylonitrile, α-cyano-ethyl-acrylonitrile and fumaronitrile can be used. Acrylic acid nitrile is the most preferred option.

The content of at least one ethylenically unsaturated monomer containing a nitrile group for the purpose of obtaining butadiene-nitrile carboxylated latex depends on the further scope of the latex and can be anything. In latex for gloves made by dipping, in particular ionic deposition, as a rule, the amount of at least one ethylenically unsaturated monomer containing a nitrile group is from 10 to 45 wt. parts, preferably from 15 to 40 wt. parts, more preferably from 25 to 35 wt. parts per 100 wt. parts of the monomer mixture.

Latexes used to produce film products by ionic deposition preferably include a carboxylic agent of the type of unsaturated carboxylic acids, since the presence of a carboxyl group in the composition of the polymer phase allows more efficient combined vulcanization of the latex film, since, on the one hand, crosslinking occurs during ionic deposition polymer due to the interaction of the carboxyl groups of the copolymer with the cation of the electrolyte-coagulant deposited on the form corresponding to the product, and on the other hand, chemical bonds are formed in the polymer matrix in the presence of vulcanizing agents. Carboxyl-containing polymers behave during ionic deposition as polymer electrolytes, the reactivity of which depends on the degree of dissociation of carboxyl groups and increases with increasing pH. In addition, the use of carboxylating agents in the composition of monomers leads to a decrease in the content of butadiene in the reaction mixture and a decrease in hard-to-remove high-boiling by-products in the dispersed phase of latexes at the degassing stage.

The carboxylic agent included in the mixture of monomers is selected from the group of ethylenically unsaturated carboxylic acids. In particular, alpha(methylene)carboxylic acids or mixtures thereof, such as, for example, acrylic, methacrylic, itaconic, fumaric acids or mixtures thereof, are used as carboxylating agents. Preferred carboxylic agents are acrylic or methacrylic acids.

Most preferred is methacrylic acid (MAA).

The content of the monomer based on unsaturated carboxylic acids in the latex for gloves is from 2 to 10 wt. parts, preferably from 2 to 7 wt. parts, most preferably from 3 to 7 wt.h. per 100 wt. parts of the monomer mixture.

According to the present invention, various functional additives can be present in the composition of the latex and determined by suitable methods, introduced into the mixture of monomers during the emulsion polymerization. Such compounds, in particular, include emulsifiers, initiators, molecular weight regulators, defoamers and other additives involved in the polymerization process.

As emulsifiers in the synthesis of carboxylated latexes for use in the manufacture of products by the method of ionic deposition, surfactants of various nature can be used: anionic, nonionic, cationic and amphoteric.

Anionic emulsifiers included in the butadiene-nitrile carboxylated latex, as a rule, are salts of alkyl (aryl) sulfonic acids selected from the group of alkyl benzene sulfonates, aliphatic sulfonates, olefin sulfonates, and salts of alkyl sulfuric acids - alkyl sulfates. In addition, various co-emulsifiers may additionally be present in the latex, in particular, non-ionic compounds of ethylene oxide with fatty alcohols, such as: lauryl, myristic, cetyl, stearic and oleic alcohols.

Preferably, the latex contains emulsifiers from the group of alkyl benzene sulfonates and alkali metal alkyl sulfates.

The most preferred among anionic emulsifiers is sodium alkylbenzenesulfonate, which can be either an individual compound, for example, dodecylbenzenesulfonate, or a mixture of homologues of various molecular weights, mainly with an alkyl radical length from C10 to C18.

As a rule, emulsifiers of butadiene-nitrile carboxylated latexes are present in dosages from 1.0 to 10 wt. parts, the preferred dosage range of the emulsifier is from 0.8 to 8.0 wt. parts, the most preferred range is from 1.5 to 6.0 wt. parts per 100 wt.h. monomers containing a carboxylated copolymer.

In accordance with the present invention, elements of a redox initiating system may be present in the latex composition, and transition metal salts such as iron, cobalt or nickel may additionally be determined in combination with a suitable complexing agent such as sodium ethylenediaminetetraacetate, sodium nitrile triacetate, trisodium phosphate or tetrapotassium diphosphate.

Latex also contains polymerization initiators such as peroxo and azo compounds.

Peroxo compounds include hydrogen peroxide, peroxodisulfates, peroxodiphosphates, hydroperoxides, peracids, peracid esters, peracid anhydrides, and peroxides with two organic residues. Sodium, potassium and ammonium salts can be used as salts of persulfuric acid and perphosphoric acid. Suitable organic hydroperoxides are, for example, tert-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide. Suitable peroxides with two organic moieties are dibenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl perbenzoate, t-butyl peracetate, and the like. Suitable azo compounds are azo-bis-isobutyronitrile, azo-bis-valeronitrile and azo-bis-cyclohexanenitrile.

The amount of hydroperoxide type initiator can be from 0.01 to 0.5 wt. hours per 100 wt. including monomer mixture, preferably from 0.02 to 0.3 wt. hours, most preferably from 0.02 to 0.2 wt.h. The amount of the persulfate-type initiator may be from 0.1 to 1.5 parts by weight. per 100 wt.h. monomer mixture, preferably from 0.15 to 1.0 wt.h., most preferably from 0.15 to 0.6 wt.h.

Compounds such as sulfenates, sulfinates, sulfoxylates, dithionite, sulfite, metabisulfite, disulfite, sugar, urea, thiourea, xanthates, thioxanthates, hydrazinium salts, amines and amine derivatives such as aniline, dimethylaniline may also be present in butadiene-nitrile carboxylated latexes. , monoethanolamine, diethanolamine or triethanolamine. The preferred redox initiating systems are, for example: 1) potassium peroxodisulfate in combination with triethanolamine, 2) ammonium peroxodiphosphate in combination with sodium metabisulphite (Na ₂ S ₂ O ₅ ), 3) p-menthane hydroperoxide/sodium formaldehyde sulfoxylate (Rongalite C ) in combination with ferrous sulfate (FeSO ₄ ), sodium ethylenediaminoacetate and trisodium phosphate; 4) cumene hydroperoxide/sodium formaldehyde sulfoxylate in combination with ferrous sulfate (FeSO ₄ ) and sodium ethylenediaminoacetate complexing agent and trisodium phosphate buffer.

The molar amount of the reducing agent lies in the range between 50-500% based on the molar amount of the used initiator and is 0.015-0.02 wt.h. The amount of complexing agent depends on the amount of transition metal used and is usually equimolar to it.

The latex preparation is carried out in the presence of a molecular weight regulator typical of an emulsion polymerization process.

Molecular weight regulators may be, in particular, organic thio compounds, which are selected from a number of compounds such as n-hexylmercaptan, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, n-hexadecylmercaptan, n-tetradecylmercaptan, t-tetradecylmercaptan, and also xanthogen disulfides, in particular such as dimethyl xanthogen disulfide, diethyl xanthogen disulfide and diisopropyl xanthogen disulfide, thiuram disulfides - tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide; halogenated hydrocarbons such as chloroform, carbon tetrachloride, hydrocarbons such as pentaphenylethane, alphamethylstyrene dimer, acrolein, allyl alcohol, 2-ethylhexyl thioglycolate, terpinolene, α-terpinene, γ-terpinene, dipentene.

The most common and commonly available molecular weight regulator is tertiary dodecylmercaptan.

All of the listed regulators can be present individually or in various combinations (two or more) in a total amount of up to 1.0 wt.h, in particular from 0.1 to 1.0 wt. hours per 100 wt.h. monomer mixture, preferably from 0.15 to 1.0 parts by weight, most preferably from 0.18 to 0.8. If the content of the molecular weight regulator is less than the specified range per 100 wt. parts, then the physical and mechanical properties of products obtained by the immersion dipping method will be significantly lower, but if the dosage of the molecular weight regulator exceeds the specified range, then the stability of the colloidal system during the synthesis will decrease, which will lead to the formation of coagulum.

Additionally, during the production of latex by the method of emulsion polymerization, buffers are used and can be determined in the composition of the latex, ensuring the stability of the pH of the medium during the synthesis. Alkali metal phosphates and pyrophosphates, such as trisodium phosphate, sodium pyrophosphate, are used as such substances. The amount of buffer is from 0.01 to 1.0 wt. parts per 100 wt.h. monomer mixture, preferably from 0.2 to 0.8 wt.h., most preferably from 0.3 to 0.6 wt.h.

In addition, latex may contain additives of substances that regulate the pH of the medium, antioxidants, antiseptics that prevent the reproduction of fungi and bacteria in the aquatic environment, etc., the introduction of which is possible during the synthesis and conditioning of latex, as well as defoamers, including also mineral oils, alcohols, esters, alkylaminosulfonates in dosages from 0.02% by volume.

Films obtained from latex do not have defects (sagging, perforations, cracks) and are distinguished by high physical and mechanical properties: during combined (salt and sulfur) vulcanization, the strength of latex films is at least 30 MPa in combination with a relative elongation of at least 500% ; the resulting films are thin, strong and transparent.

The process of obtaining butadiene-nitrile latex includes copolymerization, it can be carried out in a semi-batch mode, in which monomers and other reagents are gradually introduced into the reactor at a certain rate, but the finished latex is unloaded at a time. The production of latex can also be carried out in a batch mode, in which both the initial reagents are introduced into the reactor and, after copolymerization, the finished latex is unloaded, as well as in a continuous mode: the polymerization process is carried out in a cascade of series-connected reactors, in which copolymerization is carried out in several reactors, while the flows of reagents move at the same speed and the finished latex leaves the cascade of reactors at the same speed.

The reactor for carrying out the reaction may be an ideal mixing or displacement reactor.

The copolymerization process can be carried out using a seed, and for the synthesis of the seed latex it is possible to use various monomers, including the same monomers that are used for the main synthesis, or different from them, as well as inorganic pigments, for example, such as silicon dioxide of any origin .

The seed latex can be synthesized in situ directly in the polymerization vessel before the start of the main reaction or previously in a separate vessel and then supplied in the required amount to the reaction zone. The dosage of the seed latex can be from 0.01 to 15 wt. parts based on the total amount of monomers, preferably from 1 to 10 wt. parts, most preferably from 2 to 5 wt. parts, while the particle size of the seed latex can be, without limitation, 10-90 nm, preferably 20-80 nm, most preferably 30-70 nm. As monomers that can be used to synthesize the seed latex, the ethylenically unsaturated monomer is used either as the sole monomer or in mixture with other ethylenically unsaturated monomers or conjugated dienes.

The ethylenically unsaturated monomers for the seed latex are selected from the nitriles: acrylonitrile, methacrylonitrile, α-cyano-ethyl-acrylonitrile and fumaronitrile. In addition to ethylenically unsaturated cyanides, aromatic ethylenically unsaturated compounds such as styrene and α-methylstyrene can be used; also unsaturated acrylate carboxylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate and glycidyl methacrylate; ethylenically unsaturated amides such as acrylamide, methacrylamide, N,N-dimethylacrylamide and N-methylolacrylamide; vinyl carboxylates such as vinyl acetate; ethylenically unsaturated amines such as methylaminoethyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, 2-vinylpyridine.

As conjugated dienes, 1,3-butadiene, 2-chloro-1,3-butadiene and 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3 -pentadiene, 2-methyl-3-ethyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 1,3-hexadiene, 2-methyl -1,3-hexadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene, 3-butyl-1,3-octadiene, 3,4-dimethyl-1,3-hexadiene , 4,5-diethyl-1,3-octadiene, phenyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2,3-di-n-propyl-1,3-butadiene, 2 -methyl-3-isopropyl-1,3-butadiene, preferably 1,3-butadiene, 2-chloro-1,3-butadiene and 2-methyl-1,3-butadiene are used.

In addition, to obtain a seed latex, the use of carboxylating agents - ethylenically unsaturated acids, such as monobasic acids: (meth)acrylic acid and crotonic acid; dibasic acids: maleic acid, fumaric acid, itaconic acid, as well as their anhydrides and esters, for example dibasic acid monoesters (half-esters), such as methymaleinate, methyl itaconoate.

The following monomers are preferred for the seed latex: styrene, acrylonitrile, methyl methacrylate, butyl acrylate, 1,3-butadiene, ethylenically unsaturated acid, or mixtures thereof.

Most preferred as seeds are latexes of polystyrene, polybutadiene copolymers, carboxylated copolymer latexes based on acrylonitrile, styrene or methyl methacrylate, where ethylenically unsaturated acid is present in an amount of up to 10 wt. parts of the total mass of monomers.

It is also known (application US5750618) that inorganic pigments having a particle size of 50 to 100 nm, such as, for example, silicon dioxide of any nature, can be used as a seed.

Anionic emulsifiers such as sodium lauryl sulfate, fatty acid sulfoester salts, sodium alkylbenzenesulfonate, as well as non-ionic type emulsifiers such as ethoxylated fatty alcohols or ethoxylated alkylphenols can be used in the seed latex process. Preferably, sodium lauryl sulfate and/or sodium alkylbenzenesulfonate are used.

The amount of emulsifier used in the synthesis of the seed latex is from 1 to 20 wt.% on the total amount of monomers, in the preferred embodiment, from 2 wt.% to 10 wt.%.

To obtain a seed latex, you can also use a chelating agent - sodium ethylenediaminetetraacetate (Trilon B) or inorganic salts such as trisodium phosphate, sodium pyrophosphate.

The preparation of the seed latex is usually carried out in the presence of an initiator and a molecular weight regulator typical of an emulsion polymerization process. Typically, the initiator is selected from water-soluble persulfates, preferably ammonium or potassium persulfate is used. The amount of initiator used is in the range of 0.1 to 10% by weight, preferably 0.5 to 2% by weight, based on the total amount of monomers. The most common and commonly available molecular weight regulator - mercaptan - can be used in an amount up to 5 wt.%, preferably from 0.2 to 2 wt.%.

On the basis of the latex according to the invention, a composition can be prepared for producing film products by the dipping method. In general, the composition includes latex and vulcanizing agents. Other components are introduced into the composition at will, based on the further use of the latex product. In a particular case, to obtain gloves, a latex composition can be prepared, consisting of 96-97% latex on a dry basis, 3.0-3.6% vulcanizing agents, 0.2-0.3% salt of fatty alcohol sulfoesters or another suitable emulsifier and 0.1-0.2% antioxidant based on the total dry matter weight of the composition at 100%.

Sulfur, zinc oxide, zinc diethyldithiocarbamate, titanium dioxide can be used as vulcanizing agents for compositions for film products. Vulcanizing agents are introduced into the composition of the latex composition in the form of dispersions in the emulsifier. The emulsifier is selected from the group of any suitable emulsifiers.

Emulsifiers introduced into latex formulations act as size stabilizers for dispersed particles and prevent their agglomeration and precipitation from dispersions.

Typically, 50% dispersions of each of the curing agents are prepared, where the dosage of the dispersing agent is 1.0-8.0 parts by weight, preferably 2.0-6.0 parts by weight, most preferably 3.0-5, 0 wt.h. per 100 wt.h. dispersed ingredient, higher dosages of the emulsifier lead to unproductive costs, and lower ones do not provide the necessary level of aggregative stability of the dispersion. It is also possible to prepare a complex (total) dispersion of vulcanizing agents, which also includes an antioxidant additive.

In addition to accelerators and vulcanizing agents, additives of antioxidants (antioxidants) based on phenols, sterically hindered phenols, diphenylamine derivatives, organophosphorus compounds, thioethers, etc., can be introduced into the composition of dispersions, the main purpose of which is to suppress the processes of interaction of the resulting peroxide radicals with unsaturated bonds of polymers. The most common antioxidants used to suppress thermo-oxidative degradation are 2,2-methylene-bis(4-methyl-6-butylphenol, 4-methyl-2,6-ditert-butylphenol, 4,6-bis(octylthiomethylphenol)-o-cresol, and etc. As a rule, antioxidants are introduced into latexes in the form of dispersions in dosages of 0.10-0.50 wt.h., preferably 0.20-0.45 wt.h., most preferably 0.25-0.45 wt. of the latex polymer. parts by weight of sulfur, 1.5.0 parts by weight of zinc oxide, 1.0 parts by weight of titanium dioxide, 1.0 parts by weight of zinc diethyldithiocarbamate, 0.2 parts by weight of an antioxidant.

The latex composition for producing film products according to the invention has a solids content of 5 to 45%, preferably 8 to 35%, most preferably 10 to 33% of dry matter.

The pH of the latex composition is maintained at 8-12, preferably 8.0-10.0, most preferably 8.0-9.5. The required pH level of the composition is achieved by introducing neutralizing agents of 1-10% concentration selected from sodium, potassium, ammonia hydroxides or mixtures thereof. The resulting latex composition is subjected to aging for 24 hours at a temperature of 20-25°C with periodic gentle stirring at intervals of 3-5 hours.

Dip dipping products can be made by direct mold dipping into the latex composition or by ionic deposition. It is preferable to use the ion deposition method, when the mold corresponding to the product is immersed in a coagulating electrolyte solution (a), while the electrolyte is deposited on the surface of the mold, for which the mold is immersed in the electrolyte solution for 2-5 seconds, after which it is dried at a temperature of 25 ° C for 3-5 minutes. Then this form with an electrolyte layer (a) is immersed in the latex composition, where the polymer gel is deposited on the surface of the form for 5 seconds (b), which ensures the optimal thickness of the deposited polymer gel (0.05-0.06 mm) and the mass of the final products no more than 3.5 grams. After that, the form with a layer of polymer gel undergoes heat treatment (c).

The coagulating solution is an aqueous or alcoholic electrolyte solution, it is also possible to use a mixture of an aqueous-alcoholic solution as a solvent. The concentration of the electrolyte in the solution is 5 to 50%, preferably 10 to 40%. As coagulants, halides of 2- and 3-valent metals can be used, such as barium chloride, calcium chloride, magnesium chloride, zinc chloride, aluminum chloride, as well as barium, calcium, zinc nitrates; acetates of barium, calcium, zinc; sulfates of calcium, magnesium, aluminum. Calcium nitrate and calcium chloride, as well as mixtures thereof, are preferred.

At stage (c) in the process of heat treatment, the process of evaporation of moisture and cross-linking of polymer chains in the latex film (vulcanization) is carried out. Heat treatment, as a rule, is carried out in 2 stages: the first stage of moisture evaporation is carried out at a temperature of from 70 to 150 ° C for 1-20 minutes and the second - directly vulcanization - at a temperature of 100-180 ° C for 5-30 minutes.

During heat treatment, water evaporates from the latex film, due to which it acquires density, and strength is achieved due to the interaction of copolymer double bonds of the conjugated diene with curing agents, as well as due to the interaction of carboxyl groups with electrolyte cations deposited on the dipping mold (vulcanization ). The simultaneous action of the last two factors provides the necessary level of strength characteristics for the finished product.

Research methods

1) Molecular weight of the polymer

The determination of the molecular weight of the polymer isolated from the latex was carried out according to GOST 33418-2015 using 2 consecutively connected columns AGILENT PLGEL MIXED-C, 7.5 X 300 MM, 5 µm. The thermostat temperature of the columns is 40 degrees Celsius, the eluent is 100% tetrahydrofuran (THF). Injection volume - 100 μl, refractometric detection, detector cell temperature - 40°С, analysis time - 30 min. Column calibration to polystyrene standards in the range of 580-482,000.

2) Determination of the solubility of rubber in methyl ethyl ketone (MEK).

The method is based on the dissolution of a sample of rubber previously isolated and dried from latex in methyl ethyl ketone at a temperature of 21 ± 3°C, separation of the gel fraction using a K-52 nylon fabric filter, and gravimetric determination of the polymer content in the sol fraction.

Training. 0.25 g of rubber is cut into pieces 2×2×2mm. Dimensional deviation should not exceed ± 1mm. Clean weighing bottles without weighing are brought to constant weight in an oven at a temperature of 105 ± 3°C. The bottles taken out of the drying cabinet are kept in a desiccator and weighed, determining the weight of each bottle with an accuracy of 0.0002 g.

Testing.

0.25 g prepared according to claim 2 is weighed with an accuracy of 0.0002 g. and placed in conical flasks, pour 50 cm ^{3 of} methyl ethyl ketone with a pipette, close with a polished stopper and leave for 2 hours for the rubber to swell. Then the flask is placed on a mixing device LAB-PU-02. Mixing occurs at 125 - 135 oscillations of the platform of the device per minute.

After 3 hours, the resulting rubber solution is filtered through a K-52 cloth filter into a beaker and immediately 20 cm ^{3 of} the filtered solution are taken into a pre-weighed bottle. Evaporation of the solution is carried out in a bath. The bottle with dry residue is transferred to an oven and dried to constant weight at a temperature of 105 ± 3ºС. The bottles with dry residue removed from the drying cabinet are kept in a desiccator and weighed, determining the weight of each bottle with an accuracy of 0.0002 g.

The solubility of rubber (X) in% is calculated by the formula:

, где:X =

, where:

m ₁ - weight of the bottle with dry residue, g;

m ₀ is the weight of the bottle, g;

m _to - a sample of rubber taken for testing, g.

3) Determination of the elasticity of the raw latex gel

A sample of latex in an amount of at least 500 cm ³ is filtered through a double layer of gauze and poured into a glass with a diameter of 100 to 150 mm to obtain samples by ionic deposition. Before dipping, the surface of the latex is cleaned with filter paper from the resulting film.

Blades are cut out from the “blue tape” or “red tape” filters with a punching knife in accordance with GOST 12580-78. Then they are immersed to their full length in a fixative (40% calcium nitrate solution) for 5 seconds, carefully removed and dried for 3 minutes. After that, the drops of the fixative are removed from the lower end of the blades with filter paper and alternately immersed in latex, making sure that the blades do not touch the walls of the glass. The gel deposition time in the latex is 3 minutes. The paddles coated with raw latex gel are kept suspended in air for 5 minutes.

Then the blade is fixed in the clamps of the tensile testing machine and the relative elongation at break is determined according to GOST 12580.

The results of individual determinations are calculated to the nearest three significant figures. The test result is taken as the arithmetic mean of 10 parallel elasticity determinations, in which the allowable difference between the two most differing determinations does not exceed 150% If the difference between the two most differing determinations is more than 150%, then these two results are discarded. The number of determinations after rejection shall be at least 6, otherwise the test shall be repeated.

The test result is rounded off with a rounding step of 50% and recorded, for example, in the form of numbers: 200; 250; 300; 350 etc.

The allowable discrepancy between the two results under convergence conditions is 100%

4) Mass fraction of dry matter of latex

This parameter was determined by drying a sample of latex of a certain mass to a constant weight according to GOST 25709.

5) pH value

The determination of the pH value is carried out in accordance with GOST 11604.

6) Surface tension of latex at the interface with air

This parameter was determined in accordance with GOST 20216-74.

7) Determination of the resistance of latex to mechanical stress on the Maron device.

To this end, 75 ml of latex with a known solids content was subjected to agitation at 1500 rpm in a narrow gap between the rotor and the stator for 5 minutes. After the end of the dynamic impact, the latex was filtered through a nylon mesh, the coagulum separated from the latex was washed, dried to a constant weight at a temperature of 105°C. The amount of coagulum, expressed as a percentage relative to the total mass of the polymer in the analyzed sample, was considered as a measure of the resistance of the latex to mechanical stress. The resistance of latex to mechanical stress was determined as the amount of coagulum formed after treatment on the Maron device (Colloid chemistry of synthetic latexes: a textbook. /R.E. Neiman, O.G. Kiseleva, A.K. Egorov, T.M. Vasilyeva. - Voronezh: Publishing House of VSU, 1984. - 196 p.).

8) Film appearance

The appearance of the film was evaluated visually by the presence of defects in the form of cracks, etc.

9) Quality of latex products (gloves)

The quality of the products was evaluated for compliance with the requirements of ASTM D 6319, according to ASTM D 412.

10) Storage stability

This parameter was determined by the amount of coagulum in 1 liter of latex after keeping it in a tightly closed container for six months at a temperature of 25 and 50°C. For this purpose, at the end of the test period, the latex was filtered through a nylon mesh, the coagulum separated from the latex was washed, dried to constant weight at a temperature of 105°C. The amount of coagulum, expressed as a percentage relative to the total weight of the polymer in the analyzed sample, was considered as a measure of the stability of the latex during storage.

11) Brookfield latex viscosity

The viscosity of the latex was measured on a Brookfield viscometer according to ISO 2555:1989.

12) Determination of foaming ability of latex

The determination was carried out by a method consisting in manually shaking the latex cylinder and then measuring the volume of foam formed in the cylinder. For this purpose, 10 ml of latex was placed in a 25 ml measuring cylinder having a diameter of 20 mm, the cylinder was closed and vigorously shaken 10 times with constant force, after which the volume of the formed foam was determined.

13) Resistance of latex to the introduction of a dispersion of vulcanizing agents during the maturation of the latex mixture

This parameter was determined by the amount of coagulum in the composition after its periodic stirring for 24 hours. To do this, in 1 liter of latex, previously diluted to a dry residue of 28-32%, with stirring, vulcanizing agents were introduced in the form of 50% dispersions in an amount of 0.6 wt. sulfur, 1.5 wt.h. zinc oxide, 1.0 wt.h. zinc diethyldithiocarbamate, 1.0 wt.h. titanium dioxide per 100 wt.h. polymer. The aging of the composition was carried out for 24 hours at a temperature of 18-22°C with constant stirring at a speed of 60 rpm. After the aging time, the composition was filtered through a nylon mesh, the separated coagulum was washed, dried to constant weight at a temperature of 105°C. The amount of coagulum, expressed as a percentage relative to the total weight of the polymer in the analyzed sample, was considered as a measure of the resistance of the latex to the introduction of a dispersion of curing agents.

14) Resistance of latex to the introduction of a 5% solution of potassium hydroxide (KOH)

This parameter was determined by the amount of coagulum formed by adding a 5% alkali solution to the latex. To do this, 100 ml of a 5% KOH solution at a rate of 5 ml/min was introduced into 1 liter of latex, previously diluted to a dry residue of 28-32%, with stirring at a speed of 60 rpm. After the time of supply of the KOH solution, the latex was filtered through a nylon mesh, the separated coagulum was washed, dried to constant weight at a temperature of 105°C. The amount of coagulum, expressed as a percentage relative to the total weight of the polymer in the analyzed sample, was considered as a measure of latex resistance to the introduction of a 5% KOH solution.

15) Film stickiness

This parameter was determined organoleptically by contact of the finger with the vulcanized film. In this case, the result was evaluated by points from 0 to 5, where 0 is the absence of stickiness, 5 is high stickiness.

16) Mass fraction of free acrylic acid nitrile in latex

This parameter was determined chromatographically in accordance with TU 2294-415-05842324-2006, amended. 1-4.

17) Method for obtaining products by the method of submersible dipping:

17.1. The preparation of a mixture of coagulants for carrying out the process of ionic deposition was carried out by mixing 40 wt. parts of calcium nitrate and 60 wt. parts of water.

17.2 Preparation of 50% dispersions of vulcanizing agents was carried out in a ball mill: a sulfur dispersion was prepared for 72 hours by mixing 100 wt. parts of sulfur, 100 wt.h. water and 5 wt.h. sodium alkylbenzenesulfonate. Dispersions of titanium dioxide, zinc oxide, zinc diethyldithiocarbamate were prepared in a similar manner, with the difference that the dispersion time was 24 hours.

17.3. The preparation of the latex mixture was carried out by mixing dispersions of vulcanizing agents so that the sulfur content was 0.6 wt.h. sulfur, 1.0 wt.h. titanium dioxide, 1.5 wt.h. zinc oxide and 1.0 wt.h. zinc diethyldithiocarbamate per 100 wt. parts of dry matter, previously diluted to 25% latex concentration at a temperature of 18-25°C. The mixture was kept under constant stirring at a speed of 60 rpm for 24 hours.

17.4. The porcelain dipping mold was preheated to 55° C. and immersed in a 20% calcium nitrate coagulant solution for 3 seconds. The mold was then exposed to air for 5 minutes at and immersed in the latex mixture (17.3) for 5 seconds. Then spent exposure of the resulting polymer layer in air for 5 minutes, followed by drying at a temperature of 80°C for 20 minutes and vulcanization for 20 minutes at 110°C.

18) Latex Particle Sizing

This parameter was determined by laser diffraction on a Microtrac instrument according to ISO 13320-1.

The essence of the proposed technical solution is illustrated by the following examples of a specific implementation, which illustrate, but do not limit the scope of the claims of this invention. Those skilled in the art will appreciate that it is not limited to them and that the same effect can be achieved by applying equivalent formulas.

Implementation examples

Example 1

In a 20-liter apparatus, equipped with a stirrer and a shirt for thermoregulation, filed an aqueous phase containing 110 wt.h. deoxygenated and demineralized water, 2.5 wt.h. emulsifier (1) - sodium alkylbenzenesulfonate (ABS) and 0.4 wt.h. trisodium phosphate (TSP), 0.007 wt.h. Trilon B complexing agent and 0.0018 wt.h. iron sulfate. The apparatus was purged with nitrogen, after which a total mixture of monomers containing 65 wt.h. butadiene, 30 wt.h. acrylic acid nitrile, 5 wt.h. methacrylic acid, as well as pre-dissolved in acrylic acid nitrile molecular weight regulator tertiary dodecylmercaptan (TDM) in the amount of 0.2 wt.h. and 0.02 wt.h. pinane hydroperoxide (HPP) initiator. In addition, an initiator emulsion was prepared separately for feeding during the process, consisting of 0.01 wt.h. GSP, 0.5 wt.h. emulsifier sodium alkylbenzenesulfonate and 5 wt.h. water, as well as an activator solution containing 0.018 wt.h. rongalita in 5 wt.h. water. After 50 minutes of stirring in the reactor of the aqueous phase with the monomer mixture, the initiating system and tertiary dodecylmercaptan at a temperature of 15°C, the Rongalite solution was fed into the reactor, which was considered the start of the polymerization reaction. At monomer conversions of 25% and 50%, ½ of the prepared volume of the initiator emulsion was fed into the apparatus. The polymerization process took place at a temperature of 22°C. 12 hours after the start of the reaction, the conversion of the monomers was 70%, the mass fraction of dry matter in the latex was 33.2%. Then, a diethylhydroxylamine stopper was fed into the apparatus in an amount of 0.1 wt.h. on the polymer in the form of a 5% solution and neutralizing agent 10% ammonia solution to pH=7.5. Then the unreacted monomers were distilled off from the latex using a rotary film evaporator at 60°C and a defoamer was supplied. After that, the latex was conditioned by introducing a 10% ammonia solution until pH=8.4 was reached.

The properties of the resulting latex are shown in the tables below.

Example 2

Synthesis of latex was carried out analogously to example 1 with the difference that the content of sodium alkylbenzenesulfonate was 2.8 wt.h., the ratio of the components of the monomeric phase was 73 wt.h. butadiene, 25 wt.h. acrylic acid nitrile, 2 wt.h. methacrylic acid, TDM 0.3 wt.h. and GPP 0.015 wt.h, sodium sulfate 0.4 wt.h. The supply of the initiator emulsion in 0.2 wt.h. alkylbenzenesulfonate was carried out at a conversion of 25%.

While the polymerization process was carried out at a temperature of 20°C to achieve a conversion of 99.8% within 28 hours. The mass fraction of dry matter in latex before distillation of residual monomers was 46.8%. Neutralization of the latex to reach pH 8.3 was carried out analogously to example 1.

Example 3

Synthesis of latex was carried out analogously to example 1 with the difference that sodium alkylsulfonate was used as an emulsifier in the amount of 2.2 parts by weight, the ratio of the components of the monomeric phase was 65 parts by weight. butadiene, 32 wt.h. acrylic acid nitrile, 3 wt.h. methacrylic acid, TDM 0.3 wt.h. and GPP 0.015 wt.h., sodium pyrophosphate 0.2 wt.h. To prepare the emulsion of the initiator used 0.2 wt.h. emulsifier sodium alkylbenzenesulfonate.

The initiator emulsion was fed at 30% and 60% conversion. While the polymerization process was carried out at a temperature of 24°C to achieve a conversion of 99% within 30 hours. The mass fraction of dry matter in the latex before distillation of residual monomers was 46.6%. Neutralization of the latex until reaching pH=8.3 was carried out with a 3% KOH solution.

Example 4

Synthesis of latex was carried out analogously to example 1 with the difference that sodium lauryl sulfate was used as an emulsifier in the amount of 2.2 parts by weight, the ratio of the components of the monomeric phase was 67 parts by weight. butadiene, 30 wt.h. acrylic acid nitrile, 3 wt.h. methacrylic acid, TDM 0.4 wt.h. and GPP 0.015 wt.h., potassium pyrophosphate 0.2 wt.h. The supply of the initiator emulsion in 0.2 wt.h. sodium lauryl sulfate was carried out at a conversion of 20% and 50%. In this case, the polymerization process was carried out at a temperature of 28°C until a conversion of 99% was reached within 29 hours. The mass fraction of dry matter in latex before distillation of residual monomers was 46.0%. Neutralization of the latex until reaching pH 8.5 was carried out with a 10% ammonia solution.

Example 5

Synthesis of latex was carried out analogously to example 1 with the difference that the content of sodium alkylbenzenesulfonate in the aqueous phase was 2.3 wt.h., the ratio of the components of the monomeric phase 50 wt.h. butadiene, 45 wt.h. acrylic acid nitrile, 5 wt.h. methacrylic acid, TDM-0.75 wt.h. and GPP 0.015 wt.h., 0.15 wt.h. sodium pyrophosphate. In this case, the molecular weight regulator TDM was fed fractionally at 3 points: 0.6 wt.h. at the beginning of the process and 0.075 wt.h. at 25% and 75% conversion. To prepare the initiator emulsion, 0.4 parts by weight of sodium alkylbenzenesulfonate was used. The supply of the initiator emulsion was carried out at a conversion of 25% and 60%. While the polymerization process was carried out at a temperature of 42°C to a conversion of 99.8% within 15 hours. The mass fraction of dry matter in the latex before the distillation of residual monomers was 46.9%, the pH of the latex after neutralization with ammonia was 8.5.

Example 6

Synthesis of latex was carried out analogously to example 1 with the difference that the content of ABS in the aqueous phase was 2.5 wt.h., the ratio of the components of the monomeric phase 60 wt.h. butadiene, 33 wt.h. acrylic acid nitrile, 7 wt.h. methacrylic acid and TDM 0.18 wt.h., GPP 0.015 wt.h., 0.8 wt.h. potassium pyrophosphate. To prepare the emulsion of the initiator used 0.2 wt.h. sodium alkylbenzenesulfonate. The supply of the initiator emulsion was carried out at a conversion of 30% and 55%. In this case, the polymerization process was carried out at a temperature of 35°C to a conversion of 99.8%, the mass fraction of dry matter in the latex was 47.0%, pH after neutralization with ammonia was 8.0.

Example 7

Synthesis of latex was carried out analogously to example 1 with the difference that the content of ABS in the aqueous phase was 4.0 wt.h., the ratio of the components of the monomeric phase 68 wt.h. butadiene, 22 wt.h. acrylic acid nitrile, 10 wt.h. methacrylic acid and TDM 0.18 wt.h., GPP 0.015 wt.h., 0.6 wt.h. potassium pyrophosphate. To prepare the emulsion of the initiator used 0.2 wt.h. sodium alkylbenzenesulfonate. The supply of the initiator emulsion was carried out at a conversion of 30% and 55%. In this case, the polymerization process was carried out at a temperature of 29°C to a conversion of 99.8% within 28 hours. The mass fraction of dry matter in the latex before distillation of residual monomers was 47.6%, the pH after neutralization was 8.2.

The formulations for the preparation and properties of carboxylated nitrile butadiene latexes are given in tables 1 and 4, and the mass fractions of elements in latex films and the properties of the films are given in tables 5 and 6, respectively.

Obtaining seed latex

120 wt. parts of water, 3.5 wt. parts of the emulsifier - sodium lauryl sulfate, 0.03 wt. parts of buffer - Trilon B., 0.5 wt. parts of a dispersant based on naphthalenesulfonic acid (NF), then monomers and a molecular weight regulator are introduced - 42.5 wt. parts of styrene, 0.3 wt. parts of tertiary dodecylmercaptan (TDM), and 2.5 wt. parts of methacrylic acid. After purging the reactor with nitrogen, 55.0 wt. parts of butadiene. The resulting mixture was heated to 64°C with stirring, after which half of the calculated amount of the initiator - potassium persulfate (0.03 wt. parts) was added in the form of a 4.5% aqueous solution. The polymerization was carried out up to 65% conversion of the monomers, then the remaining amount of the initiator was introduced. The process was carried out up to 100% conversion of the monomers. The resulting dispersion was cooled to room temperature and used to obtain the target latex.

Synthesis formulations and seed latex properties are shown in tables 2 and 3

Seeded Latex Examples (8-11)

Example 8

The target latex was prepared in a 2 liter steel autoclave equipped with a stirrer and thermostatic jacket. The reactor was loaded with 5 wt.h. seed latex (recipe 1), 90 wt.h. water, initiator - potassium persulfate 0.6 wt.h., sodium tetrapyrophosphate 0.2 wt.h., complexing agent - disodium salt of ethylenediaminetetraacetic acid 0.05 wt.h. In a separate reactor equipped with a stirrer and a thermostatic jacket, a mixture of monomers was prepared, consisting of 30 wt.h. acrylic acid nitrile, 4 wt.h. methacrylic acid, 0.4 wt.h. TDM, in which, after purging the reactor with nitrogen, 52 wt.h. butadiene. The reactor with monomers after loading all the ingredients was cooled to a temperature of 5°C. In addition, a mixture of 30 wt.h. was prepared in a separate container. water and 2.0 wt.h. emulsifier sodium alkylbenzenesulfonate. At the first stage of the reaction, the autoclave containing water-soluble ingredients and the seed was heated to 30°C, after which the first monomer mixture was continuously fed into it, and an aqueous solution of the emulsifier was simultaneously supplied for 5 hours. The polymerization temperature was 40°C. 1 hour before the end of the supply of the first part of the monomer mixture, the supply of the second part of the monomer mixture, consisting of 13 wt.h. butadiene, 1 wt.h. MAC and 0.4 wt.h. TDM. The monomer mixture was fed for 5 hours with parallel dosing of the emulsifier solution mixture. The temperature in the polymerizer was maintained at the level of 38-40°C, the polymerization was carried out to a dry residue of 47.4 wt.% (99.2% conversion). The resulting latex after the introduction of ammonia until pH=7.5 was subjected to distillation of residual monomers on a rotary-film evaporator at a temperature of 55°C and a pressure not exceeding 55 mm Hg.

Example 9

Synthesis of latex was carried out similarly to synthesis 8 on a seed (recipe 2) with the difference that the first monomer mixture contained 50 wt.h. butadiene 0.5 wt.h. TDM, as a buffer used 0.2 wt.h. potassium tetrapyrophosphate and the dosage of sodium alkylbenzenesulfonate was 3.0 wt.h. The second monomer mixture contained 15 wt.h. butadiene. The conversion of the monomers was 99.1%, the mass fraction of dry matter was 48.0%.

Example 10

Synthesis of latex was carried out analogously to example 8 on a seed (recipe 3) with the difference that 0.1 wt.h. was used as an initiator. pinane hydroperoxide and an activating complex containing 0.005 wt.h. ferrous sulfate and 0.05 wt.h. rongalita in the presence of 0.8 wt.h. trisodium phosphate, 2.5 wt.h. sodium alkylbenzenesulfonate. The conversion of the monomers was 99.5, the mass fraction of the dry matter of the latex was 45.2%.

Example 11

Synthesis of latex was carried out analogously to example 1 with the difference that sodium alkylbenzenesulfonate in the aqueous phase - 6.2 wt.h., the ratio of the components of the monomeric phase 60 wt.h. butadiene, 33 wt.h. acrylic acid nitrile, 7 wt.h. methacrylic acid and TDM 1.2 wt.h., GPP 0.02 wt.h., 0.1 wt.h. sodium pyrophosphate. To prepare the emulsion of the initiator used 0.2 wt.h. sodium alkylbenzenesulfonate and 5 wt.h. water. The supply of the initiator emulsion was carried out at a conversion of 30% and 55%. The polymerization process was carried out at a temperature of 20°C to a conversion of 75%, the mass fraction of dry matter in the latex was 36.2%, pH after neutralization with ammonia - 8.0.

Example 12

Synthesis of latex was carried out analogously to example 1 with the difference that the content of ABS in the aqueous phase was 1.8 wt.h., the ratio of the components of the monomeric phase 60 wt.h. butadiene, 33 wt.h. acrylic acid nitrile, 7 wt.h. methacrylic acid TDM was absent, GSP - 0.025 wt.h., 0.8 wt.h. sodium pyrophosphate. To prepare the emulsion of the initiator used 0.2 wt.h. sodium alkylbenzenesulfonate and 5 wt.h. water. The initiator emulsion was fed at three points at a conversion of 30%, 55%, and 90%. In this case, the polymerization process was carried out at a temperature of 40°C until a conversion of 100%, the mass fraction of dry matter in the latex was 47.8%, the pH value after neutralization with ammonia was 8.0.

Example 13

A latex sample was obtained by mixing in a ratio of 1:1 in terms of dry matter of the two samples obtained in example 11 and example 12. The mass fraction of dry matter was 41.3%.

The formulations for the preparation and properties of the obtained carboxylated butadiene-nitrile latexes are given in Tables 1 and 4, and the mass fractions of elements in latex films and the properties of the films are given in Tables 5 and 6, respectively.

Table 1.

Latex synthesis recipes

Components, (wt. parts per 100 wt. parts of the monomer mixture.) Purpose of the component Example number one 2 3 four 5 6 7 eight 9 ten 11 s 12 s 13 s seed latex - - - - - - - 5
(recipe 1) 5
(recipe 2) 5
(recipe 3) - - Latex sample - a mixture of latexes according to examples 11+ 12 in a ratio of 1: 1 Butadiene monomer 65 73 65 67 fifty 60 68 52+13* 50+15* 52+13* 60 60 NAC monomer thirty 25 32 thirty 45 33 22 thirty thirty thirty 33 33 POPPY monomer 5 2 3 3 5 7 ten 4+1* 4+1* 4+1* 7 7 TDM Molecular weight regulator 0.2 0.3 0.3 0.4 0.75 0.18 0.18 0.4+0.4** 0.5+0.4** 0.5+0.4** 1.2 0 Sodium alkylbenzenesulfonate emulsifier 3.0 3.0 - - 2.7 2.7 4.2 2.00 3.00 2.50 6.4 2.0 Sodium alkylsulfonate emulsifier - - 2.4 - - - - - - - - - Sodium lauryl sulfate emulsifier - - - 2.4 - - - - - - - - Trilon B Chelating agent 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.05 0.05 0.05 0.05 0.05 ferrous sulfate Component of the activating complex 0.018 0.018 0.018 0.018 0.018 0.018 0.018 - - 0.005 0.0018 0.0018 Pinane hydroperoxide initiator 0.03 0.025 0.025 0.025 0.025 0.025 0.025 - - 0.10 0.030 0.035 Rongalit activator 0.018 0.018 0.018 0.018 0.018 0.018 0.018 - - 0.05 0.018 0.018 Potassium persulfate initiator - - - - - - - 0.6 0.6 - - Trisodium phosphate Buffer, electrolyte 0.4 - - - - - - - - 0.8 - - Sodium pyrophosphate Buffer, electrolyte - - 0.2 - 0.15 - - 0.2 - - 0.1 0.8 Potassium pyrophosphate Buffer, electrolyte - - - 0.2 - 0.8 0.6 - 0.2 - - - Sodium sulfate electrolyte - 0.4 - - - - - - - - - - Water Dispersion medium 115 115 115 115 115 115 115 120 120 120 115 115 Monomer conversion, % - 70.0 99.8 99.0 99.0 99.8 99.8 99.8 99.2 99.1 99.5 75.0 100 The presence of coagulum in latex - - - - - - - - - -

*portion of MAC and butadiene supplied 4 hours after the start of dosing of the main mixture of monomers

**portion of TDM, served after 4 hours, together with the second portion of butadiene and MAC

Here and below, examples 11, 12 and 13 are comparative.

Table 2. Seed latex synthesis recipes

Compound Components, wt.h Item number Recipe 1 Recipe 2 Recipe 3 Dispersion medium Water 130 130 130 Chelating agent Trilon B 0.03 0.03 0.03 Dispersant Leucanol 0.5 0.5 0.5 Emulsifier Sodium lauryl sulfate 3.5 3.5 3.5 Monomers Styrene 43 98 - NAC - - - MMA - - 98 Butadiene 55 - - Methacrylic acid 2.0 - one Acrylic acid - 2.0 one Initiator ammonium persulfate 0.1 0.1 0.1

List of abbreviations given in Table 1:

NAC - Acrylic Acid Nitrile

MMA - methyl methacrylate

Table 3. Physicochemical properties of seed latexes

Prescription number Mass fraction of dry matter, wt. % Volume average particle diameter, nm one 44.0 74 2 43.8 72 3 42.8 69

Table 4. Colloidal-chemical properties of latexes

Name of indicator Example No. p / p one 2 3 four 5 6 7 eight 9 ten 11 s 12 s 13 s Mass fraction of dry matter, % 33.2 46.8 46.6 46.0 46.9 47.2 47.6 47.4 48.0 45.2 36.2 47.8 41.3 pH 8.4 8.3 8.3 8.6 8.5 8.0 8.2 8.6 8.4 8.2 8.0 8.0 8.0 Surface tension, mN/m 32.2 31.1 33.0 35.5 34.7 41.0 35.0 33.0 32.2 34.8 29.6 36.2 31.4 Average particle diameter, nm 80 95 99 90 98 174 106 150 98 107 144 210 162 Brookfield viscosity, mPa s 35 33 29 37 42 eleven 65 33 52 43 135 17 83 Resistance to mechanical stress, % coagulum 0 0 0 0 0 0 0 0 0 0 0 7.5 5.2 Foaming ability, cm ³ /: 12/5 11/4 10/5 11/4 11/4 29/27 22/22 12/5 12/4 12/4 22/20 8/6 11/8 Storage stability for 6 months, % coagulum
at 25°C
at 50°C 0.15
0.34 0.04
0.06 0
0 0.12
0.18 0.07
0.16 0.32
0.28 0.015
0.02 0.19
0.34 0
0 0.10
0.15 2.8
3.2 7.8
11.4 5.1
7.1 Mass fraction of free acrylic acid nitrile, % Less than 0.010 Resistance to the introduction of a dispersion of vulcanizing agents, % coagulum 0.1 0.15 0.12 0.11 0.06 0.18 0.05 0.09 0.07 0.08 5.8 7.2 5.9 Resistance to the introduction of 5% KOH, % coagulum 0 0 0 0 0 0 0 0 0 0 6.2 7.8 6.1

As can be seen from the data presented, the latex samples according to examples 11-13 (comparative examples) had a lower resistance to the introduction of vulcanizing agents and the introduction of a 5% KOH solution. In addition, for these samples, when filtering the dispersion immediately after synthesis, the presence of coagulum in the latex was noted.

Table 5. Properties of polymer isolated from latex

Name of indicator Example No. p / p one 2 3 four 5 6 7 eight 9 ten 11 s 12 s 13 s Average particle size, S, nm 80 93 99 90 175 70 150 106 98 107 144 211 121 Solubility of the polymer in MEK, p, wt.% 95.2 54.6 42.2 63.2 92.1 30.0 47.2 54.0 56.0 58.0 100.0 12.4 30.2 Number average molecular weight, M _n , g/mol 72324 65845 78345 46470 26850 70112 75344 44187 46317 45812 22413 121344 54067 Weight average molecular weight, M _w , g/mol 253134 187588 235035 130288 53700 350000 188233 88374 100971 100786 42584 667392 271416 Polydispersity, M _w /M _n 3.50 2.85 3.00 2.80 2.00 5.00 2.50 2.00 2.18 2.20 1.90 5.50 5.02 A= 100*S*p/(Mn+Mw) 2.34 2.00 1.33 3.22 22.0 0.50 2.69 4.32 3.73 4.23 22.15 0.33 1.12 Elasticity of raw gel, % 1050 1300 1300 1450 1550 1000 1100 1600 1600 1600 ˃1600 250 200

Table 6. Physical and mechanical characteristics of vulcanized latex films obtained by ion deposition

Name of indicator Example No. p / p Norm according to ASTM6319 one 2 3 four 5 6 7 eight 9 ten 11 s 12 s 13 s Film appearance Homogeneous smooth + + + + + + + + + + - - - Film stickiness 0 0 0 0 0 0 0 0 0 0 0 3 3 2 Film thickness, mm Not less than 0.05 0.085 0.089 0.087 0.081 0.083 0.083 0.085 0.089 0.083 0.088 0.090 0.079 0.070 Stress at 300% elongation, MPa - 4.6 4.9 5.2 4.8 5.2 5.4 6.2 5.5 7.4 6.9 1.2 10.2 8.4 Conditional tensile strength, MPa At least 25 30.8 30.4 30.7 34.8 34.4 32.1 35.3 39.0 45.3 39.2 20.2 22.4 20.2 Elongation at break, % At least 500 550 560 580 600 640 550 540 650 650 660 900 220 360

"+" defect-free, uncolored, transparent film

"- " the presence of defects in the film in the form of cracks, perforations, lack of gloss, sagging (different thickness)

As can be seen from the data presented in tables 5 and 6, for samples of latexes according to the invention, characterized by the values of the solubility index A in the range from 0.5 to 22 wt.% * nm * mol * g - ¹ and the polydispersity of the latex polymer M _w /M _n from 2 to 5, characterized by a high level of strength characteristics of vulcanized latex films.

At the same time, for latex samples according to the invention, the values of raw gel elasticity are in the optimal range - from 1000% to 1600%. Those skilled in the art know that there is a direct relationship between the elasticity of a green gel and the relative elongation of a vulcanized film. At raw gel elasticity values of more than 1600%, the relative elongation is also very high, products based on such latex are too soft, sticky, viscous.

The appearance of the wet gel for latexes according to the invention is uniform; no defects (streaks, cracks, holes, etc.) were noted on the test specimens (blades). These values of the elasticity of the raw latex gel according to the invention indicate the high quality of the latex films formed during the dip dipping process.

In addition, it is noted that the stress at 300% elongation for samples of vulcanized films obtained from latexes according to the invention has lower values than for films according to examples of comparison 11-13, which, in turn, provides greater comfort and tactile sensitivity when using the glove. In addition, the presented data show that the proposed technical solution makes it possible to obtain films without external defects and increased stickiness.

Claims (18)

1. Latex for the manufacture of products by immersion dipping, including structural units formed from at least one monomer, which is a conjugated diene, at least one ethylenically unsaturated monomer containing a nitrile group, and at least one monomer, which is an unsaturated carboxylic acid, in which the value of the solubility index (A), calculated by the formula A \u003d 100 * p * S / (M _n + M _w ), is from 0.5 to 22 wt.% * nm * mol * g - ¹ , where p is the solubility of the polymer in methyl ethyl ketone (wt.%), S is the particle size of the latex (nm), M _n is the number average molecular weight of the tetrahydrofuran-soluble part of butadiene-nitrile latex (g/mol), M _w is the weight average molecular weight of the soluble in tetrahydrofuran tetrahydrofuran parts of butadiene-nitrile latex (g/mol), while the value of the polydispersity of the latex polymer M _w /M _n is from 2.0 to 5.0. 2. Latex according to claim 1, in which the value of the solubility index A is from 1.0 to 15 wt.% * nm * mol * g - ¹ , preferably from 1.0 to 10 wt.% * nm * mol * g - ¹ . 3. The latex according to claim 1, in which the polydispersity value of the latex polymer M _w /M _n is from 2.0 to 4.0, preferably from 2.0 to 3.5. 4. The latex according to claim 1, wherein the conjugated diene is selected from the group consisting of 1,3-butadiene, 2-chloro-1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1 ,3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 1 ,3-hexadiene, 2-methyl-1,3-hexadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene, 3-butyl-1,3-octadiene, 3,4 -dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, phenyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2,3-di-n-propyl -1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, preferably a conjugated diene is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3-pentadiene , most preferably the conjugated diene is 1,3-butadiene. 5. Latex according to claim. 1, in which the amount of conjugated diene is from 50 to 85 wt.h. per 100 wt. parts of the monomer mixture, preferably from 60 to 75 wt.h., most preferably from 63 to 70 wt.h. 6. The latex according to claim. 1, characterized in that the amount of ethylenically unsaturated monomer containing a nitrile group is from 10 to 45 wt.h. per 100 wt. parts of the monomer mixture, preferably from 15 to 40 wt.h., most preferably from 25 to 35 wt.h. 7. Latex according to claim 1, characterized in that the unsaturated carboxylic acid is selected from alpha (methylene) carboxylic acids and mixtures thereof, preferably from acrylic, methacrylic, itaconic, fumaric acids and mixtures thereof, most preferably from acrylic and methacrylic acids and their mixtures. mixtures. 8. Latex according to claim. 1, characterized in that the amount of unsaturated carboxylic acid in the latex is from 2 to 10 wt.h. per 100 wt.h. monomer mixture, preferably from 2 to 7 wt.h., most preferably from 3 to 7 wt.h. 9. Composition for submersible dipping containing latex according to any one of paragraphs. 1-8 and at least one curing agent. 10. Composition for obtaining products by the method of submersible dipping, consisting of 96-97 wt.% latex according to any one of paragraphs. 1-8 in terms of dry matter, 3.0-3.6 wt.%, at least one vulcanizing agent, optionally 0.2-0.3 wt.% salt of fatty alcohol sulfoesters and 0.1-0 .2 wt.% antioxidant based on the total weight of the dry matter of the composition in 100 wt.%. 11. A latex-based dipped product according to any one of paragraphs. 1-8 or composition according to paragraphs. 9, 10. 12. The product according to claim 11, which is a glove. 13. The use of latex according to any one of paragraphs. 1-8 for the manufacture of dipped products, in particular gloves.