DE1544970A1 - Use of polycarbodiimides for vulcanization of polymers - Google Patents

Description

fatentanwältI

DR.-ING. BY KREISLER DR.-ING. SCHDNWALD DR.-ING. TH. MEYER DR "FUES DR. EGGERT DIPL.-PHYS, GRAVE

COLOGNE T, DEICHMANNHAuV

Cologne, 13 «5oW5

The B.F. Goodrich "Company, Akron, Ohio (V.St.A.).

Use of polyearbodiimides for the vulcanization of polymers

The invention relates to a method for producing crosslinked polymers by reacting polymers containing organic acids and polycarbodiimides ₀

It is known from UoS ₀ JU patent 2 937 164 that polymers containing organic acids can be mixed with monocarbo diimides of the general formula

where R and R * are aliphatic, cycloaliphatic and araliphatic radicals, can crosslink «If R and R» are aromatic radicals, the monocarbodiimides do not cause the vulcanization of polymers containing organic acids, unless the mass is set to 50-50 for about 24 hours. It has surprisingly been found that aromatic polyoarbodiimides polymers which contain organic acids vulcanize after a short time at room temperature, whereas aromatic monocarbodiimides do not vulcanize these polymers at room temperature. Furthermore, gels of polymers containing organic acids formed with monocarbodiimide crosslinking bridges are soluble in alkaline solutions, while similar polymers formed with polyoarbodiimide crosslinking bridges are insoluble in alkaline solutions such as ammonium hydroxide.

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Slowly vulcanizing compounds of polymers containing organic acids are valuable as embedding compounds and for the production of sealants and spreading compounds, binders for propellants and fuels, Als slow is called a vulcanization that takes place at room temperature over a period of several hours as opposed to takes place in a few minutes «," Insensitivity to Alkali compounds is another important property of those made with polycarbodiimide crosslinking bridges Materials.

Polycarbodiimides generally react less quickly with polymers containing organic acids than the corresponding monocarbodiimides, poly (dicyclohexylcarbodiimide) gels a liquid polymer composed of 67 parts of butadiene, 24.4 parts of acrylonitrile and 9.6 parts of methacrylic acid at room temperature in 30 minutes to 2 Hours. Monomeric ET, N ¹ -bicyclohexyl carbodiimide gels the same polymer in just 1-1.5 minutes. It was also found that monomeric U, 1T ^I -diphenylcarbodiimide, a liquid interpolymer of 55 parts of butadiene, 25 parts of acrylonitrile and 20 parts of methacrylic acid does not gel at room temperature, while poly (diphenyloarbodiimide) gel formation in this polymer is non-sticky Polymers containing water-soluble organic acids and dispersions and emulsions of these polymers in water can be effectively crosslinked with water-soluble polycarbodiimides and with dispersed garbodiimides.

The term "polycarbodiimide" used here denotes compounds which contain 2 or more intralinear carbodiimide groups of the formula 4N = G = ET) ^- and correspond to the general formula 4κ · "Ν = * 0 = ^ _χ , where χ is a whole Number from 2-500 and R is a divalent organic radical. Polycarbodiimides of the structure 4R-N = C = H ^ _x , where R is alkylene, arylene or aralkylene, are particularly suitable for the purposes of the invention, these radicals preferably totaling 1- t8 carbon atoms

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contained particularly "preferred for the purposes of the invention are polycarbodiimides in which H is a phenylene radical in the o-position to the group -H = O *! - one or more Contains substituents,. which are bulky enough to suppress the reactivity of the group -H = CKU- » Examples of such substituents are methyl, ethyl, isopropyl, t-butyl and heopentyl,

The invention also includes polymers of the formula

-Pr-

ΉΕ t

ON

I Λ

where R and χ have the meaning already mentioned «These Polymers have the property of tautomerization under Formation of polymer chains with side chain orbodiimide groups

Ε ι

Il

NH

Polymers also fall within the scope of the invention general formula

N = OsJ- Η »,

where R and χ have the meaning already mentioned and R * for hydrogen, an alkyl radical with up to 6 carbon atoms or can stand an aryl radical with up to 18 G atoms. The for amount of the polycarbodiimide suitable for the purposes of the invention is 0.01-50 parts by weight of that containing the organic acid Polymer to be crosslinked, with 0.5-10 parts being particularly preferred «

It has also been found that polycarbodiimides have advantageous

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can be used in combination with other known vulcanization systems for polymers containing organic acids. It is well known that solid carboxy-butadiene-aorylnitrile compounds can be easily vulcanized with zinc oxide. If, in addition to the zinc oxide, a polycarbodiimide is added to the vulcanization batch at the same time, a combination of characteristics of both vulcanization systems is obtained in the vulcanizates; polycarbodiimides can also be used in combination with vulcanization systems based on amines, sulfur, isocyanates and epoxy resins. The advantages of combining vulcanization systems are particularly evident when liquid polymers containing organic acids are vulcanized at room temperature «. For example, a liquid polymer having terminal carboxyl groups, vulcanizable with epoxy resins, but only upon application of heat ₀ The vulcanization takes many days not occur if the connection is maintained only at room temperature · If the polycarbodiimide Ymere pole together with epoxy resin in the is mixed in, the vulcanization by the polyoarbodiimide takes place within a few hours at room temperature with the formation of a solid, stable mass, with further aging at room temperature, the vulcanization by the epoxy resin forms completely, whereby a preferred combination of physical properties of the vulcanized polymer is obtained .

Leave the alkylene, arylene and aralkylene polyarbodiimides see the method of U.S. Patent 2,941,966 Heating organic diisocyanates in the presence of a Easily produce catalyst. The reaction can be shown as follows

> 4R-N «O = K ^ _x + χ 0O ₂

Here R is a divalent organic residue and χ is one integer greater than 1. Any organic alkylene, arylene or aralkylene polyisocyanates, i.e. any organic Compounds that include two or more free Beoyanat groups

9 0 9 Ö U / "! U 8 ^{ß /} - οπτ; π.

pen can be used to produce the polycarbodiimides «. The organic polyisocyanates can Contain substituent groups, but these must not be reactive with the isocyanate groups. Phospholines, phospholine oxides and sulfides are used as catalysts and phospholidine oxides and sulfides are preferred. The reaction takes place between the isoyanate groups to form a A large number of carbodiimide bonds take place, with carbon dioxide being released «When using mixtures of two or more organic diisooyanates in the reaction is the divalent organic radical R in the formula 4 (R-Ir = G = Er). not in everyone repeating unit of the same «When prepared from organic diisooyanates, the polycarbodiimides are essentially linear"

Representative organic diisocyanates that may be mentioned are: 2,4-tolylene diisocyanate, m-phenylene diisocyanate, i ^ -diiaopropylphenylene - ^^ - diisocyanate, 1-methyl-3,5-diethylphenylene diisooyanate, 4,4'-methylene (di -p-phenylene) diisooyanate, 4-chloro-1,3-pkenylene diisocyanate, 4,4 ^t -biphenylene diisooyanate, 1,9-naphthylene diisooyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, deoamethylene diisocyanate, 1 $ 4-oyolohexylene diisooyanate, 4-isoycanoate and 1-methylene diisocyanate , S-Tetrahydronaphthylindiisooyanat. For the purposes of the invention, the aromatic diisocyanates are preferred »

Organic triisocyanates such as 2,4> 6-triisocyanatotoluene and p-IsQoyanatphenyl-2,4-diisocyanatphenyläther can im Within the scope of the invention for the production of polyoarbodiimides to be used »When using Iriisooyanaten included the polymers formed have a multitude of carbodiimide bonds. They have a high molecular weight and are strongly crosslinked. In general, diisooyanates are formed from uncrosslinked Polyoarbodiimides are preferred.

The term "organic acid-containing polymers" denotes essentially linear synthetic polymers which,

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based on aas weight, _{contain at least O 3} 005 chemical equivalents of organic acidic hydrogen per 100 parts by weight of the polymer and have molecular weights above 500. These polymers can at room temperature liquid or solid ₀ The main chain of the polymer may be selected from hydrocarbon, consist .or polyether polyester. The organic acid-containing polymers suitable for the purposes of the invention can be prepared by customary processes of emulsion polymerization, solution polymerization and bulk polymerization. The emulsion batches that are used to produce these interpolymers consist of a mixture of monomers, suitable emulsifiers and suspending agents, buffering agents for the ρ ,, control and

Xl

free-radical forming catalysts Peroxydtyp, such as the above-mentioned catalysts ₀ benzoyl peroxide, hydroperoxides such as di-t-butyl peroxide, diazo components such as azobisisobutyronitrile, and redox materials, Z ₀ Bo persulfate-sulfite combinations or mixtures thereof. The polymerization can be carried out in the presence of a catalyst which forms free radicals in a closed vessel in an inert atmosphere and under autogenous pressure or under artificially set pressure or in an open vessel under reflux at normal pressure. The polymerization temperatures can be between ^{0 0} O or below and 100 ⁰ G or above and are preferably 20-90 ⁰ G. They are largely dependent on the activity of the monomers and the catalyst used and on the desired molecular weight of the polymer product Conditions and catalysts used are similar to those used in emulsion polymerization »Polymers prepared in solution are sometimes soluble end products, and in certain cases the polymers separate from the polymerization medium during their formation» Bulk polymerizations are carried out by converting the catalyst into a monomer mixture given and the polymerization is effected in the absence of a diluent. "Liquid polymers for the purposes of the invention are naoh the above

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called the usual methods involving chemical modifying agents or chain transfer agents, for example meroaptans, sulfides, disulfides, bromotriochloromethane, Dibromodichloromethane, cumene and xylene.

Liquid polymers containing carboxyl groups as terminal functional groups and not randomly scattered along the polymer chain are also known and can be prepared by polymerizing monomers in the presence of initiators that introduce end groups and modifying agents with bis-structure «In these polymerizations The solvent used is preferably methanol, the initiator preferably 4.4 ^l -azo-bis (4-oyanvaleric acid) and the modifying agent preferably dithiobutyric acid, as described in German Patent 1,150.

The term "organic acid" is used for the purposes of Invention defined as a moiety containing an organic acidic ionizable hydrogen atom "Examples of functional groups that contain organic acidic ionizable hydrogen are carboxylic acid, phosphonic acids Sulfonic acids and sulfhydryl groups · These groups can occur as functional end groups and / or be randomly distributed along the polymer chain

The organic acids containing polymers which are suitable for the purposes of the invention, can be more accurate than interpolymers of at least one unsaturated monomer define, at least one monomer is a _f · a ß-olefiniech unsaturated organic acid of the type mentioned above. Examples of α, β-olefinically unsaturated organic acids are acrylic acid, α-alkyl-substituted acrylic acids in which the alkyl radicals contain 1-6 carbon atoms, oc-halogenated acrylic acids, such as α-fluorine, α-chlorine, a-bromine and a-iodoacrylic acid, a-gyanacrylic acid, a-phenylaoryl acid, a- (ring halogenated phenyl) acrylic acids, maleic acids,

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alkyl-substituted maleic acids whose alkyl radicals contain 1-6 carbon atoms, fumaric acid, alkyl-substituted fumaric acids, their Alkyl radicals "containing 1-6 carbon atoms, crotonic acid, cinnamic acid, styrenes carboxylated on the ring, carboxylated c-alkyl styrenes on the ring, whose alkyl radicals contain 1-6 carbon atoms, styrenes sulfonated on the ring, oc-alkylstyrenes sulfonated on the ring, their Alkyl residues contain 1-6 carbon atoms, and α- and ß-sulfonated acrylic acids »

Other monomers used in the organic acid containing interpolymers according to the invention are Butadiene, 2-alkylbutadienes whose alkyl radicals contain at least 1 and not more than 6 carbon atoms, 2,3-dialkylbutadienes with 1-6 carbon atoms in the alkyl radicals, 2-halobutadienes, Piperylenes, isobutylene, acrylic acid esters of aliphatic alcohols with 1-12 · C atoms, methacrylic acid esters of aliphatic Alcohols with 1-12 carbon atoms, acrylonitrile, methacrylonitrile, vinylidenecyanide, vinyl halides, such as vinyl fluoride, Vinyl chloride and vinyl bromide, styrene, oc-alkylstyrenes with t ~ 6 carbon atoms in the alkyl radicals and styrenes alkylated on the ring with 1-6 carbon atoms in the alkyl radicals «,

For the purposes of the invention, the following polymers are preferred: polybutadiene with terminal carboxyl groups, Butadiene methgicrylic acid polymers with terminal carboxyl groups, Butadiene-acrylonitrile copolymers with terminal carboxyl groups, butadiene-acrylonitrile-methaoryl acid copolymers with terminal carboxyl groups, polyacrylic acid, partially hydrolyzed polyacrylonitrile with at least 0.005 equivalents on carboxyl hydrogen and interpolymers of acrylic acid esters with acrylic acid, acrylic acid esters with methacrylic acid, Aoryl acid esters with methacrylic acid and acrylic acid, Butadiene and methacrylic acid, butadiene and acrylic acid, butadiene and styrene and methacrylic acid, butadiene and acrylonitrile and methacrylic acid, chloroprene and acrylic acid, chloroprene and methacrylic acid, butadiene and acrylonitrile and ethylene sulfinic acid and oc-sulfonylated polyacrylic acid. Of the

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Acrylic acid and methacrylic acid esters *! become the lower ones Alkyl esters or those "preferred whose alkyl alcohol content contains 1 to about 8 O atoms" The proportions of the monomeric Ingredients can be varied in any way, provided that at least O | OO5 chemical equivalents (based on the weight) of organic acidic hydrogen in per 100 g of polymer having a molecular weight of at least 500 can be installed.

The invention relates to the production of new crosslinked polymers, ranging from gel-like masses to solid ones vulcanized rubbery products are sufficient. According to the invention, synthetic polymers containing organic acids contained, converted into these new gel-like masses and solid vulcanized rubber-like products at room temperature, by treating these polymers with polycarbodiimides are obtained, with crosslinked, organic acids-containing polymers are obtained which are opposite to alkali compounds are insensitive. ,

The exact mechanism of crosslinking involved in the reaction between polymers and organic acids Polyoarbodiimides takes place according to the invention is not known · If the acid groups are in the end position or in located near the end position on the polymer chains, leads the reaction with polyoarbodiimides leading to chain extension and crosslinking

The crosslinked products according to the invention vary in their nature physical properties from looker crosslinked gels to solid vulcanized products, depending on the molecular weight of the originally used organic acids containing polymers, the proportion of acidic, ionizable hydrogen in the polymer and the ratio of the polyoarbodiimide to the polymer in the reaction. When liquid, organic acid-containing polymers of low molecular weight (500-2000) are used as starting materials, the products of the reaction with polyoarbodiimides vary

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from loose gels to the "cheesy" phase to rubbery Masses, depending on the type of starting polymer.

The crosslinked products according to the invention can be produced from solid polymers containing organic acids by customary Maatizier and Tulcanization processes with the less reactive polycarbodiimides. Polymers containing liquid synthetic, organic acids can be processed to the mixture and cast in molds and subsequently cured with polycarbodiimides, said conformal, infusible, solid _s rubbery and gel-like bodies are obtained.

Solutions of solid, organic acid-containing polymers and undiluted liquid, organic acid-containing Polymers are applied to surfaces and then treated with polycarbodiimides, with vulcanized protective coatings and decorative films are made. Porous objects made of wood, ceramics, leather and paper can come up with solutions of solid organic acid containing polymers and neat liquid organic acid containing polymers are impregnated, and the products obtained can by treating the impregnated article with desired Polyoarbodiimides are vulcanized.

Benzene, toluene, 3ylene, hexane, methyl ethyl ketone and similar organic solvents are thickened by adding the appropriate amount of a polyamide to a solution of an organic acid-containing polymer in one of these solvents. With polycarbodiimides plated forms liquid polymers or a solution of an organic acid-containing polymer are immersed in an organic solvent can be used in latexes, wherein a vulcanized film of the polymer according to - the form of the coated mold is formed, when the mold is taken out of the immersion medium " The mixtures of liquid, organic acid-containing polymers and polyoarbodiimides according to the invention are suitable as sealing compounds, putties, binders for solid fuel

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fabrics, binders for nonwovens made of cotton fibers, wool fibers, synthetic fibers, asbestos fibers, leather dust and wood flour, for sealing porous articles and for improving the -Y / water and oil resistance of leather and fabrics _β

It is possible to reduce the vulcanization rate of the organic acid-containing polymers with polycarbodiimides by adding small amounts of amines, such as triethylamine, triamylamine, dodecylamine, hexamethylenediamine and ammonia, to the mixture of polymer and polycarbodiimide. The volatile amines, such as triethylamine and Ammonia, are particularly advantageous for the production of coatings, dip coatings and paints because vulcanization can be delayed by choosing an amine that evaporates at the desired rate. Furthermore, the vulcanization rate of normally slow-reacting polycarbodiimides can be increased in all of the processes described above by using the ί
get heated "

treated substances to a temperature of 50-200 ⁰ C

The invention is further illustrated by the following examples. The amounts of the ingredients relate to the weight, unless otherwise stated.

example 1

In 400 cm of benzene, 0.4 mol of phenyl isothiocyanate and Dissolved 0.2 mol of hexamethylenediamine. The mixture is 1 hour heated with stirring on the reflux condenser. That filtered Product, 1,6-diphenylthioureahexane, appears as a white, crystalline solid recovered

In 380 cm of tetrahydrofuran, 0.1 mol of the prepared Bis-thiourea, 0.25 mol of yellow mercury (II) oxide and 0.24 moles of anhydrous sodium sulfate mixed «The mixture is refluxed for 30 minutes under nitrogen. The cooled, filtered product is analyzed «

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It consists of bis (phenyl-propylenecarbodiimide) or 1,6-diphenylcarbodiimidohexane. This compound is a bis-carbodiimide and representative of the simplest form of a polyaarbodiimide of the formula (GgHc -N = C = NR-) ₂ "where R is the divalent tr! Methylene group",

A carboxybutadiene-acrylonitrile polymer with 0.09 equivalents of carboxyl per 100 parts of polymer is produced as a 50% solution in tetrahydrofuran, slightly more than a theoretical equivalent of the 1,6-diphenylcarbo- produced. Diimidohexane is added. Gel formation takes place after 15 minutes at tree temperature. The gel is not sticky, but soft and rubbery.

The gelled polymer is split in half. A part is placed in distilled water, the other in a mixture of ammonium hydroxide and water (2: 1). After 72 hours the polymer is unchanged "It is resistant to water and alkali",

If an equivalent of NjN'-diisopropylcarbodiimide, a monomeric material, is used to gel the carboxy copolymer, the vulcanized material will become soft, degraded and re-fluid when immersed in 10-yellow ammonium hydroxide for 24 hours _e

When chemical equivalents of the carboxy-butadiene-acrylonitrile copolymer and N, N ^t -diphenylcarbodiimide, N, N * -di-o-toyl-carbodiimide, or N-phenyl-N'-isopropylcarbodiimide are mixed, no gel or evidence of crosslinking occurs after 48 hours at room temperature to “A gel is asi? after several hours, namely about 24 hours, when it is ^{heated to 50 °} C. in the drying cabinet. The same is the case when twice the equivalent amount of the N, N'-diphenylcarbodiimide is mixed with the carboxyl copolymer _e

When chemical equivalents of the carboxy! Butadiene-acrylonitrile copolymer and of the N, N »-dioyclohexylcarbodiimide or a Excess of the latter to be mixed at room temperature,

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gel formation takes place in less than 5 minutes. This Gelled polymer is divided into two halves One part goes into distilled water and the other part into one Mixture of ammonium hydroxide and water (2: 1) given · After 24 hours a slight disintegration of the gel in the Water recognizable. The disintegration of the gel in a mixture of ammonium hydroxide and water is complete. The polymer has liquefied again and partially dissolved.

This example shows the aromatic monocarpic odiimide an organic acid containing polymer at room temperature not vulcanized, while an aliphatic monocarbodiimide vulcanized the same polymer in a few minutes Example also shows the aliphatic monocarbodiimide cause a rapid vulcanization of polymers containing organic acids, but that opposed to the vulcanizates alkaline solutions are sensitive, while the polymers from vulcanization with polycarbodiimide are sensitive to alkali compounds are insensitive «,

Example 2

A polyoarbodiimide, namely poly (1-methyl-3,5-diisopropyl ~ 2,4-phenylcarbodiimide), which has a molecular weight of about 1720 and obtained in the manner described by heating 3,5 ~ diisopropyl-2,4-toluylene diisocyanate with 3-methyl-1-phenyl-3-phospholine is used as a crosslinking agent for an ethyl acetate-acrylic acid-methacrylic acid terpolymer (95: 2.5: 2.5) used »

10 g of the carboxypolyethyl acrylate (0.065 equivalents of carboxyl per 100 parts of polymer) are dissolved in methyl ethyl ketone to form a 50% solution. Then 0.5 g of the polycarbodiimide are added dusted into the solution «After 24 hours the polymer is crosslinked«,! Liquid is no longer present. Aromatic polycarbodiimides trigger vulcanizations in liquid, organic acid-containing polymers at room temperature

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Example 3

10 g of carboxy polyethyl acrylate (0.065 lq.uivalen.te carboxyl / 100 parts of polymer) are prepared as a 50% solution in methyl ethyl ketone. Then 1.25 g of poly (1-methyl 1-3,5-diisopropyl-2,4-phenylcarbodiimide ) with a molecular weight of 1720 in 10 g of methyl ethyl ketone added. “After 2 hours there was no sign of heat development and vulcanization. After 5 hours the mixture is as thick as molasses “After 5.5 hours the material does not flow when the container is turned over. ! After 7 hours, the reaction mixture is jelly-like. After 24 hours, the mixture has the appearance of synthetic resin ("art-gum"). It is crumbly, but does not stick to a glass rod _{or the like}

The vulcanized polymers is overall in four equal parts divided ^s ₉ which are treated as follows:

Part A remains in the air in an unsealed vessel «, part H is covered with distilled water. Part G is covered with 15% ammonium hydroxide. Part D is covered with 30% ammonium hydroxide «,

After 17 days, the samples show no signs of swelling or disintegration To vulcanize 2,6-diethylphenylcarbodiimide, ergifcfc after No vulcanization for 48 hours at room temperature

Polymeric carbodiimides trigger vulcanization in organic acid-containing polymers at room temperature, while this is not the case with monomeric aromatic carbodiimides under the same conditions »

Example 4

A liquid carboxyl-terminated polybutadiene is made by adding 100 parts of butadiene and 4 parts Polymerized azodioyanovaleric acid in 100 parts of t-butanol in a polymerization bottle at 75 ° C. for 8.6 hours «The polymer has a functionality of 2, one

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Sign that both terminal groups of the molecules are carboxyl groups are * A solution of 10 ropes of polycarbodiimide in 10 parts of dibutyl phthalate is added to 100 parts of this polymer, a plasticizer <> The G-emic is left over power stands at room temperature, with non-stick, solid polymers are formed.

Tensile strength- fracture- Shore A-strength, p elongation hardness kg / om 2L ——

Ao polymer plus poly (tri—

alkyl-1 _? 3 ~ phenyl-carbodiimide),

in which the alkyl radicals are methyl,

Ethyl and .Isopropyl are and

the latter predominates. "9.8 720 32

B ₀ polymer plus poly (I, 3-

dialkyl-2,4-phenylcarbodiimide),

wherein the alkyl radicals are methyl and

Are isoprepyl and the latter

predominates. . 17.5 270 50

If 10 parts of the polycarbodiimide used in B and 10 parts of dibutyl phthalate to 100 parts of a butadiene-acrylonitrile polymer With terminal carboxyl groups, it forms in 3 hours at room temperature a non-sticky material.

Example 5

A solid, butadiene-acrylonitrile copolymer differs from it with 0.065 equivalents of carboxyl per 100 parts of polymer is used as cement with $ 20 total solids in methyl ethyl ketone manufactured. Pöly (trialkyl-1,3-phenylcarbodiimide), in which the alkyl radicals are methyl, ethyl and isopropyl, whereby the latter predominates, is added and mixed in well on the roller mixer for 30 minutes A doctor blade set to 0.63 mm is cast on a glass plate. The PiIm is dried overnight at room temperature Type G test bars are tested on an Instron tensile testing machine with a feed of the clamping clamp of 50 cm / min, checked*

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Polycarbodiimide tensile strength elongation horny kg / om J ₀

3 - 18.2 1010

5 32.2 490

If the butadiene-acrylonitrile copolymer, which is roughly the contains the same proportions of these monomers as the above-mentioned copolymer, but is not carboxy-modified, in the same way as cement with $ 20 total solids is prepared in methyl ethyl ketone, no vulcanization "takes place at room temperature if per 100 parts of the 5 parts of the polycarbodiimide are added to the polymer and the mixture is left to stand at room temperature for 24 hours will. This shows that organic acidic hydrogen must be present in the polymer in order to react with polyoarbodiimides To get vulcanization.

Example 6

Polyethyl acrylate and polybutyl acrylate with terminal carboxyl groups (both with molecular weights of about 6000) are vulcanized with 10 parts of the polycarbodiimide used in Example 5 per 100 parts of polymer in 16 hours to give non-adhesive polymers. If the same polymers are mixed with 10 parts of o-tolylcarbodiimide, a monomeric aromatic material, no vulcanization can be observed, even if it is ^{kept at 50 °} C. for 24 hours ο

2 g samples of the polyalkyl acrylates are covered with a solution of concentrated ammonium hydroxide in water (2: 1) and Left to stand for 1 week «, no deterioration, softening or any other sign of a decline in vulcanization is detected «,

Example 7

Mixtures are made from 100 parts of a solid, carboxyl-modified Polymers of butadiene, acrylonitrile and methacrylic acid (0.065 equivalents / 100 parts polymer). 40 parts

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FEP carbon black and the following additives:

A. Without additive (comparative sample) j

B. 0.5 part of poly (trialkyl-1,3-phenylcarbodiimide), wherein the Alkyl radicals are methyl and isopropyl, the latter predominating;

C. 3.5 parts of polycarbodiimide and

D. 7.0 parts of polycarbodiimide.

The mixing is carried out on a cold rolling mill. The mixtures are vulcanized at 170 ° C. for 20 minutes.

Sample ;

Modulus at $ 300 elongation, kg / cm ² l6.4 29.5 117 Tensile strength, kg / cm ² 29.4 72 258 185 elongation, % 1460+ 955 615 265

These values indicate that aromatic polycarbodiimides are effective vulcanizing agents for rubbers which contain organic acid.

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Claims (1)

Claims i. "'Use of polyearbodiimides for vulcanization of ~ "Polymers that contain organically bound acid residue groups in contained in the polymer chain » 2. Use of polyearbodiimides of the formula in which R is a hydrocarbon radical with 1 to about 18 carbon atoms and χ is a number from 2 to 500, for the purposes of claim 1. Use of polyearbodiimides of the formula N = C = NR ¹ in which R and χ have the abovementioned meaning and R ^{1 is} hydrogen, an alkyl radical having up to 6 carbon atoms or an aryl radical having up to 18 carbon atoms, for the purposes of claim 1. Use of polyearbodiimides that are tautomeric in their Form of the formula ■ R NH are present, in which R and χ have the meaning given above for the purposes of claim 1. 5. Use of polyearbodiimides according to Claims 2 to 4, in which R is an alkylene, arylene or aralkylene radical to 18 carbon atoms, preferably a phenylene radical, for the purposes of claim 1. 6. Use of polyearbodiimides according to claim 5, in which R is a phenylene radical which is in the ortho position to the carbodiimide group is substituted for the purposes of the claim 9098 U / 1 148. "___ _t BATH ORIGINAL