DE2531623A1 - METHOD FOR MANUFACTURING LIGHT POLYCHLOROPRENE RUBBER - Google Patents

Description

Bayer Aktiengesellschaft

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509 Leverkusen. Bayerwerk

E / Cm 1 4 JUL11975

Process for the production of light-colored polychloroprene rubbers

The invention relates to a process for the production of light-colored polychloroprene rubber types in an aqueous-alkaline manner Emulsion in the presence of free radical initiators, certain emulsifier systems being used as emulsifiers reach.

The production of polychloroprene has long been known and, for example, in Ullman's Encyclopedia of Technical Chemie, Stuttgart, Volume 9, pp. 336 ff., Urban publishing house and Schwarzenberg, Munich-Berlin 1957 and in Encyclopädia of Polymer Science and Technology, Vol. 3, pages 705-730, John Wiley, New York 1965.

The process takes place in two stages, the polymerization to the latex being carried out in the first stage and in the second stage the processing of the latex to solid rubber, for example by freeze coagulation or electrolyte precipitation, he follows.

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The implementation of the Polymerisationsatule is for example U.S. Patents 2,394,291 and 2,567,117; British Patents 512,458 and 1,094,321 as well as in German Offenlegungsschrift 2 241 394.

The processing of the latex by freeze coagulation is described in, among others

Chem. Engng. Progr. 43, 391 (1947) and in the German Patent 1,051,506. The processing of the latex by electrolyte precipitation and the subsequent drying in Schnecken is described in the German patent 1,111,804.

Freeze coagulation, however, is the preferred work-up method represent.

The application properties of the chloroprene polymers are largely determined by the polymerization temperature:

A product manufactured at a lower temperature has a strong tendency to crystallize and is ideally suited for the production of adhesives.

For example, polychloroprene produced at a higher temperature can be used as a rubber with valuable properties use.

The processing is carried out in the same way in all cases:

The alkaline latex that has accumulated during the polymerization is adjusted to pH by adding dilute acetic acid 5-7 and so sensitized.

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During this acidification, the emulsifiers lose waste acid and / or saturated and unsaturated fatty acids have their effect. The latex would coagulate uncontrollably if there would not be another surface-active compound in the latex which would give the latex a certain stability confers. The condensation product of naphthalenesulfonic acid and formaldehyde is usually used for this purpose used in the form of an alkali salt (see R. S. Barrows and G.W. Scott, Ind.eng. Chem. 40, 2193 (1948)).

Alkylnaphthalene sulfonates, e.g. Use diisopropyl or diisobutyl naphthalene sulfonate.

The latex stabilized with naphthalene sulfonates coagulates irreversibly on the surface of a rotating cooling roller the end.

The thawed, washed and mechanically pressed film is then put in a belt dryer with the aid dried by IR radiation and / or hot air.

This process represents a noticeable thermal or radiation load for the polymer. Usually shows the polychloroprene Je dried in this way a more or less strong brown tone depending on the extent of the load during the drying process.

However, polymers with a slight brown intrinsic color can be used, for example, to produce mixtures for Car whitewall tires or for the production of plastics for bright ^ transparent, "discoloration-free adhesions" cannot be used.

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There is thus a need to provide a polychloroprene polymer that has a very light inherent color as a solid as well as a solution in suitable organic solvents.

Surprisingly, it was found that a very bright Polychloroprene rubber, which is obtained after the process of freeze coagulation with subsequent drying of the film in a belt dryer with IR radiation and / or hot air Can be worked up, can be produced if instead of the costabilizers previously used based on condensation products other suitable compounds can be used from naphthalene sulfonic acid and formaldehyde.

The invention thus provides a process for the production of polychloroprene with a light inherent color by free radical polymerization of chloroprene, which can contain up to 30% by weight of a comonomer copolymerizable with chloroprene, in an aqueous alkaline emulsion in the presence of free radical initiators at temperatures of 0-60 ⁰ C in the presence of emulsifier systems containing alkali salts of disproportionated abietic acids and / or saturated and unsaturated fatty acids, characterized in that alkali salts of alkyl sulfonates, alkyl sulfates and / or alkyl phosphates are used as further surface-active substances.

Sodium and potassium are exemplary as alkali metals mentioned. The alkyl chains are straight or branched, saturated or unsaturated and have as many carbon atoms as as required for a surface-active effect is. The alkyl chains preferably have 8 to 40 carbon atoms. You can optionally also through oxygen atoms

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. 5.

be interrupted. Furthermore, the alkyl chains be substituted with 1 to 5 hydroxyl groups and / or 1 to 5 ethoxy groups with 1 to 10 carbon atoms. The following alkyl radicals are listed as examples: methyl, ethyl, propyl, isopropyl, butyl, isomeric butyl, Pentyl, hexyl, heptyl, octyl, nonyl, decyl.

Alkyl sulfonates are compounds whose alkyl radicals have the group -SO, * ■ ~ ' ; alkyl sulfates are compounds whose alkyl radical has the group -O-SO ^ "'and whose compounds are called alkyl phosphate,

( 2- ) whose alkyl radical has the groups -0-Po ₃ ^v 'or -0-PO ₂ -O-,

The following compounds are listed for illustration: R denotes an alkyl radical having preferably 8 to 40 carbon atoms.

rO-SO ₃ ® Me®
(RO-PO ₃ ^{2 Θ} ) 2 Me®
R-CO-O-CH ₂ -CH ₂ -SO ₃ ⁰ Me®

R-CH-COcP Me®

R-CH-COO-R ¹ (R ¹ = C ₁ -C ₁₀ -AlCyI)

SO ₃ ⁰ Me®

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R "(R" «C ₁ -C ₁₀ alkyl or -

R-CH-COO®
^ ⁵

Me®

R-CH-COO-R " ¹ (R ¹ "

0-SOp

R-CH-CO-NH-R "» (R "" = H; C ₁ -C ₁₀

I _{ft A} -CH ₂ -OC ₁ -C ₁₀ -AIkYl)

0-S0 ₃ ^@ Me® 2 1

-0-SO ₅ ⁰ Me® m = 1-15

R-COO-CH ₉ -CH-CH ₉ -O-SO, ⁰ Me "

OH

(R-CO-O-CH ₂ -CH-CH ₂ -O-PO ₃ 2

OH

R-OOC-CH-CH ₂ -COQ-R
^ Me®

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R-CONH- (CH ₂ ) -0OC-CH-CH ₂ -COO- (CH ₂ ) -HN-COOR

t SO, ® Me® y =

The following are examples of the surface-active compounds used according to the invention:

C ₁₂ H ₂₅ -O-SO ₃

C ₁₂ H ₂₅ -CH COO® S0 ₃ Na ®

C ₁₀ H ₂₁ -CH-COO-IC ₃ H ₇ SO ^ Na®

C ₁₇ H ₃₅ -CO-N-CH ₂ -CH ₂ -SO ₃ ⁰ Na®

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C ₁₂ H ₂₅ CH

-COO ⁰

₀ H ₂₁ -CH-COO-IC ₃ H ₇

C ₁₀ H ₂₁ -CH-CO-NH ₂

0-SUN

3 Na ^v

₁₃ H ₂₇ -C0-NH-

N / A*

C ₁₁ H ₂₃ COO-CH ₂ -CH-CH ₂ -O-SO ₃ OH

(2-) _Λ C ₁₁ H ₂₃ CO-O-CH ₂ -CH-CH-O-PO ₃

OH

-00C-CH-CH ₂ -C00-CqH _1? SO® · Na © ■

C ₁ -, H ₂₃ -CO-MH. (CH ₂ ) ₄ -00C-CH-CH ₂ -C00- (CH ₂ J ₄ -NH-CO-C ₁ .

S0 ₃ © Na®

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As alkali salts of disproportionated abietic acid, the sodium or potassium salts may be mentioned by way of example. the disproportionated abietic acids themselves and their preparation are described in US Patents 2,154,629 and 2 201 237. They are made, for example, by the disproportionation of wood resins such as rosin, won. The alkali salts can be used in amounts from 3 to 6 parts by weight, preferably from 3.5 to 5.5 parts by weight be added per 100 parts by weight of monomer.

The sodium or potassium salts are exemplary as alkali salts of saturated and / or unsaturated fatty acids mentioned. The following compounds, for example, may be mentioned as fatty acids with 6 to 25 carbon atoms: caproic acid, Caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, Caproleic acid, lauroleic acid, oleic acid, elaidic acid, Eicosenoic acid, erucic acid, linoleic acid.

The fatty acid salts can be used in amounts of 2.5 to 5.0 parts by weight, preferably from 3 to 4 parts by weight per 100 parts by weight of monomer are added.

The compounds which can be used according to the invention are used in amounts which have a surface-active effect guarantee. The appropriate amounts can easily be determined by any person skilled in the art. As a particularly cheap one The amount range is considered to be 0.4 to 1.5 parts by weight per 100 parts by weight of monomer.

The polymerization is known as emulsion polymerization performs, being a discontinuous

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-40

or continuous process is possible.

The known, free Compounds that generate radicals are used, such as potassium peroxydisulfate, Hydrogen peroxide, water-soluble salts of persulphuric acid, organic peroxides (p-menthane hydroperoxide, Benzoyl peroxide, lauryl period, tert.-buty! Hydroperoxide) and in a particularly advantageous manner formamidinesulfinic acid according to German Auslegeschrift 1 097 689.

The polymerization can be carried out in the temperature range from 0 to 60 C:
is preferred.

be carried out, the range from 10 to 50 ° C

The use of the emulsifier systems described requires pH values of the emulsion greater than 10, with a pH range of 12.0 to 13.5 is particularly favorable.

Between 60 and 80 % of the monomer is converted in order to obtain products with good application properties.

Unreacted organic compounds can be removed by steam distillation, for example remove absolute pressure of 20 torr.

Steam distillation, for example at 50 ⁰ C and one

When carrying out the process, chloroprene can be polymerized on its own or up to 30 % can be replaced by another compound copolymerizable with chloroprene, such as monoviny compounds (acyl nitrile, methacrylonitrile, vinylidene chloride, eC-chloroacrylonitrile, methacrylic acid esters, acrylic acid esters), vinyl-substituted aromatic compounds ( Styrene, vinyl toluenes) and conjugated diene compounds (butadiene (1,3), 1-chloro-butadiene (1,3), 2,3-dichlorobutadiene (1,3), 2-chloro-3-methyl- butadiene- (1,3)).

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The structure and properties of the polymers can be modified by adding known modifying compounds, such as mercaptans, xanthogen disulfides, benzyl iodide and Iodoform can be varied within wide limits.

The latices were made by freeze coagulation with subsequent drying of the film according to the German patent 1 051 506 processed into solid rubber.

To assess the color, the polymers produced with various surface-active compounds were used in Dissolved toluene (20% by weight), cast 1 mm thick films from this solution and, after drying, their color sample cards (RAL) of the Committee for Delivery Conditions and Quality Assurance at the German Standards Committee (DNA), 6 Frankfurt / M.1 Gutleutstrasse 163-167> assigned.

The following examples are intended to explain the invention in greater detail without, however, restricting it.

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Example 1 - Test according to the prior art

A mixture of the following was used to prepare the polymer
Composition polymerized under nitrogen atmosphere:

Chloroprene 100.00 parts by weight

n-dodecyl mercaptan 0.15 part by weight

Phenothiazine 0.01 part by weight

Desalinated water 120.00 parts by weight sodium salt of a disproportionate

Abietic acid 4.0 parts by weight

Caustic soda 0.65 parts by weight

Sodium salt of the condensation product 0.65 parts by weight from naphthalenesulfonic acid and formaldehyde

The polymerization was carried out ^{at 40-42 ° C. by}
a 1% aqueous solution of formamidinesulfinic acid
continuously flowed to the approach.

At a monomer conversion of 65-70 % , the remaining
Monomers removed by steam distillation in vacuo
and the polymer by freeze coagulation followed by
Drying according to DBP 1.051.506 isolated.

The color corresponds to RAL 1015.
Example 2

The polymer was prepared as described in Example 1.
Instead of the condensation product from naphthalenesulfonic acid
and formaldehyde became 0.4 parts by weight of surfactant
^C 12-15 ^ Ky3- ^su 3- ^fonfi rt (as sodium salt) used.

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The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 3

The polymer was prepared as described in Example 1. Instead of the condensation product from naphthalenesulfonic acid and formaldehyde were 0.7 parts by weight of 1,3-bis-2-ethylhexy] J-glycerol ether sulfate (as sodium salt) used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 4 - Experiment according to the prior art

For the production of the polymer was analogous to the example
of British patent 1,094,321 polymerized a mixture of the following composition under a nitrogen atmosphere.

Chloroprene 100.00 parts by weight

n-dodecyl mercaptan 0.14 part by weight

Desalinated water 140.00 parts by weight

Sodium salt of a disproportionate 6.0 parts by weight of abietic acid

Caustic soda 0.6

Sodium salt of the condensation product 0.7
from naphthalenesulfonic acid and formaldehyde
Potassium peroxydisulfate 0.1 part by weight

Parts by weight parts by weight

The polymerization was carried out at 10 C by
a 1 # aqueous solution of formamidinesulfinic acid

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continuously flowed to the approach.

At a monomer conversion of 65-7096, the remaining monomer was removed by steam distillation in vacuo, and the polymer obtained by freeze coagulation with subsequent drying according to German patent 1,051,506. The color corresponds to RAL 1015.

Example 5

The polymer was prepared as described in Example 4. Instead of the condensation product of naphthalenesulfonic acid and formaldehyde, 0.40 parts by weight of surface-active paraffin sulfonate (as the sodium salt) (C ₁₂ -C ₁₅ -AlkVl) were used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 6 - Test according to the prior art

The polymer was prepared as described in Example 4. Instead of the condensation product from naphthalenesulfonic acid and formaldehyde, 0.5 parts by weight of diisobutylnaphthalene sulfonate (as the sodium salt) were used.

The latex was worked up as described in Example 1. The color corresponds to RAL 1015.

Example 7

The polymer was prepared as described in Example 4. Instead of the condensation product from naphthalenesulfonic acid and formaldehyde were 0.7 parts by weight of 1,3-bis / 2-

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äthylhexyi] -glycerinäther- ^3υ1ίοΐ ( ^as sodium salt) used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 8

The polymer was prepared as described in Example 4. Instead of the condensation product of naphthalenesulfonic acid and formaldehyde, 0.7 parts by weight of sodium a-hydroxy-octadecanesulfonic acid were used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 9

The polymer was prepared as described in Example 4. Instead of the condensation product of naphthalenesulfonic acid and formaldehyde , 0.7 parts by weight of a secondary sodium _{alkyl sulfate (C 12} -C ₁₄ -A ^ JSyI) were used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

Example 10

The polymer was prepared as described in Example 4. Instead of the condensation product of naphthalenesulfonic acid and formaldehyde, 0.5 part by weight of a monolauryl acid glyceride sulfate was used.

The latex was worked up as described in Example 1. The color corresponds to RAL 1013.

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Example 11

The polymer was prepared as described in Example 4. Instead of the condensation product from naphthalenesulfonic acid and formaldehyde became 0.7 parts by weight of the N-octadecyl disodium sulfosuccinic acid amide used.

The latex was worked up as described in Example 1. The color corresponds to RAL 9001.

The evaluation of the hues can be expressed in words as follows:

RAL 9001 much lighter than RAL 1013 and RAL 1013 noticeably lighter than RAL 1015.

The examples clearly show the advantages of the surface-active substances according to the invention over the conventional ones used condensation products of aromatic sulfonic acids.

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Claims (7)

Claims; 1. Process for the production of polychloroprene with a light inherent color by radical polymerization of chloroprene, which can contain up to 30 wt .- # of a comonomer copolymerizable with chloroprene, in aqueous alkaline emulsion, in the presence of radical initiators at temperatures from 0 to 60 ⁰ C in Presence of emulsifier systems containing alkali salts of disproportionated abietic acids and / or saturated and unsaturated fatty acids, characterized in that alkali salts of alkyl sulfonates, alkyl sulfates and / or alkyl phosphates are used as further surface-active substances. 2. The method according to claim 1, characterized in that the polymerization in the presence of 3 to 6 parts by weight Alkali salts of disproportionated abietic acid is carried out. 3. The method according to claim 1, characterized in that the polymerization in the presence of 2.5 to 5.0 parts by weight is carried out on alkali salts of fatty acids. 4. The method according to claim 1, characterized in that the polymerization in the presence of 0.4 to 1.5 parts by weight is carried out on alkali salts of alkyl sulfonates, alkyl sulfates and / or alkyl phosphates. 5. The method according to claims 1-4, characterized in that the polymerization at temperatures of 10 to 50 ⁰ C is performed. 6. Process according to Claims 1-5, characterized in that the monomer used is converted between 60 and 80 % . Le A 16 556 - 17 - 609885/0945 7. Polychloroprene produced by a process of Le A 16 556 - 18 - 609885/0945