DE2042081A1 - Disalts of sulphocarboxylic acids - for sepg natural and synthetic rubbers - Google Patents

Abstract

The use of the di-salts of alpha-sulphocarboxylic acids having a chain length of 8-26C and alkali metals, Mg, NH4 or short-chain aliphatic (alkanol) amines as sepg. agents gives good action without the drawbacks associated with powder e.g. talcum. they do not affect the adhesion of further coatings onto the rubber and are cheaper than, e.g. silicone oil.

Description

"Release agents for elastomers" The invention relates to the use voncz - sulfocarboxylic acid salts as release agents for natural and synthetic elastomers.

For example in the manufacture of rubber goods from natural and synthetic rubber, release agents are required once after production the unvulcanized rubber mixture causes the skins or blanks to stick together Prevent until further processing and on the other hand, the adhesion of the unvulcanized Prevent rubber mixture in the vulcanization mold and thus easy removal from the mold of the vulcanizate.

As a release agent for elastomers there are already a large number of different Products that are roughly divided into two classes, the powdery ones, have become known and the liquid release agents. As the best-known representative of the powdery Release agents are e.g. talc or zinc stearate. Main disadvantages these powdering agents are their dust development in the manufacturing plant, as well as the partly poor weldability of the blanks treated with talc or corn powder during vulcanization.

One tries to avoid the disadvantageous dust development of the powder compositions to counteract the fact that the powdering agent is slurried in an aqueous phase which are then pulled into the unvulcanized rubber compound pelts.

There is another possibility of counteracting the disadvantages mentioned in the fact that powdering agents are completely dispensed with and liquid release agents are used, among which those based on fatty acids because of their economic efficiency and the possibility of to be used in aqueous solution, still have the greatest importance. In many cases where release agents based on fatty acids do not have a sufficient release effect develop, e.g. silicone oils and fluorinated oils are mainly used as mold penetrants Hydrocarbons used as release agents. Besides the higher prices own However, these products have the disadvantage that part of the release agent transferred to the vulcanizate the adhesion of a subsequently applied finish or paint is disadvantageous influence and also the bonding of the vulcanizate to form a composite article impede.

The present invention is therefore based on the object of release agents find that have a very good separating effect, but the ones described above Do not have disadvantages.

This object is achieved in that one disalts from α-sulfocarboxylic acids a chain length of 8 - 26 carbon atoms and alkali metals, magnesium, ammonium, short-chain aliphatic amines or short-chain aliphatic Alkanolamines used as release agents for natural and synthetic elastomers.

As an anion component of the disalts used according to the invention are for example the following 4 - sulfocarboxylic acids: g - sulfocaprylic acid, oC- Sulfocapric acid, - sulfolauric acid, ot- sulfo-hydrogenated coconut fatty acid, e - sulfomyristic acid, g- sulfopalmitic acid, α- sulfostearic acid, M- sulfohydrated nut oleic acid, g - sulfo-hydrogenated rapeseed oil fatty acid, sulfo-hydrogenated palm kernel fatty acid, α-sulfo-hydrogenated soy fatty acid, & - sulfo-hydrogenated tallow fatty acids, α-sulfohydrated fish and trans-fatty acids, tz-sulfobehenic acid.

Furthermore, α-sulfocarboxylic acids can be used, which are obtained by sulfonation of synthetic fatty acids, for example by paraffin oxidation Carboxylation of organometallic compounds such as organoaluminum Compounds, by oxidizing cleavage of olefinic compounds or by others Oxidation reactions, for example ozonization of olefins and subsequent oxidizing cleavage of ozonides with oxygen, or produced in another way have been.

The production of the α- - sulfocarboxylic acids can be carried out according to known methods Process, for example by complete or partial sulfonation of the corresponding Fatty acids by means of sulfur trioxide. The further processing to the disalts is then done by neutralizing the sulfocarboxylic acids obtained with the corresponding one Base, with the possibility of producing mixed salts by initially carried out a partial neutralization with one base and the Neutralization is completed.

The disalts to be used according to the invention can also be considerable Contain amounts of ester salts of sulfocarboxylic acids.

The disalts used according to the invention are used as the cation component the alkali metals sodium, potassium, lithium, also magnesium, ammonium, short-chain aliphatic amines with 1 - 4 carbon atoms such as ethyl, ethyl, propyl, isopropyl and butylamine and short-chain aliphatic alkanolamines such as mono-, di- and triethanolamine in question.

The disalts of the alkali metals are of particular importance Sodium and potassium too.

As special in both technical and economic terms the di-sodium resp.

Di-potassium salts of oC sulfocarboxylic acids with a chain length of 12-18 carbon atoms to address. They primarily include products which are derived from naturally occurring fats and blends.

According to the invention as a mold coating or layer release agent for natural or synthetic elastomers to be used disalts of the sulfocarboxylic acids are expediently in aqueous solution and a concentration of 0.1 to lo% by weight, preferably 0.2 to 2% by weight, are used.

To achieve certain effects, it is possible in a known manner water-soluble polymers to improve film formation and increase viscosity add to the solutions.

Carboxymethyl cellulose, hydroxyethyl cellulose, for example, are suitable and methyl cellulose. The products are usually sold individually in technical grade used, but mixtures of the compounds with one another and with Emulsions of silicone oils and fluorocarbons can be used.

To achieve a good separating effect between unvulcanized rubber heads these are expediently coated with the solution of the release agent, sprayed or immersed in the solution. Can be used as a mold coating the forms made of steel, aluminum or chrome-plated steel with the aqueous solutions brushed or sprayed and the water evaporates.

Although usually water as the solvent for the invention is preferable to be used release agent, it is on the other hand for certain Application forms, e.g. in spray cans, also possible, additional organic solvents, such as methylene chloride or lower alcohols, to be used alone or as a mixture.

The following examples are intended to provide the subject matter of the present invention explain in more detail without restricting it to it.

EXAMPLES 1) In these experiments, the release effect was that according to the invention to be used bG i-sulfocarboxylic acid salts and various other release agents investigated on cast polyurethane elastomers. The following polyurethane products were made used.

Mixture a) Soft polyester polyurethane.

100 g of linear polyester (commercial product Desmophen 2000 (R) from the paint factories Bayer AG) 18 g of naphthylene-1,5-diisocyanate (commercial product Die modur 15 (R) der Farbenfabriken Bayer AG) 2.3 g of a mixture of 80% crosslinker B and 20% crosslinker TR (commercial products from Farbenfabriken Bayer AG) Mixture b) Hard polyester polyurethane.

100 g of linear polyester (commercial product Desmophen 2000 (R) from the paint factories Bayer AG) 30 g of naphthylene-1,5-diisocyanate (commercial product Desmodur 15 (R) from paint factories Bayer AG) 7 g Crosslinker H (commercial product of the paint factories Bayer AG) mixture c) polyether polyurethane.

loo g reaction product of polytetramethylene ether glycol with excess Toluylene diisocyanate (commercial product Adiprene L loo from Du Pont) 12.5 g of 4,4-methylene-bis-2-chloroaniline (Commercial product Moca from Du Pont) The aforementioned raw materials were used accordingly the specified mixing ratios in the usual way, mixtures at elevated temperature manufactured according to the instructions of the raw material suppliers and cast in steel molds, those previously cleaned intensively and after cleaning twice with those in the following Solutions mentioned in the table. Before the filling, the Molds preheated to loo to llo ° C. The temperature in the polyurethane compositions was in the case of the mixtures a) and b) approx. 1300 C, in the case of the mixture c) 100 ° C. at the time the filling. The curing of the polyurethane compositions took place with the mixture a) and with the mixture c) for 3 hours at llo ° C, while the mixture b) during Was cured at llo ° C for 24 hours. Then each was demolded and here the force required for demolding is subjectively determined. The results of the Experiments are given in the table below.

The products listed below were used as mold release agents used in the form of an o, 5 win, aqueous solution.

Release agent A) Alkali salt of a fatty acid derivative, commercial product Levaform K B) ammonium alkyl phosphate, Ha Aquarex L (R) C) sodium alkyl sulfate, Hande Aquarex D (R) D) sodium lauryl ether sulfate product Texapon N 25 E) ammonium lauryl ether sulfate Commercial product Texapon NA F) Triethanolamine-lauryl-ä Commercial product Texapon NTR G) Triethanolamine-lauryl-sulfon product Texapon TH H) Xylene sulfonate, commercial product Eltesol (R) I) Cumene sulfonate K) Turkish red oil, sulfation sr commercial product Sykanol DKM L) Turkish red oil, degree of sulfation approx. 65%, commercial product Sykanol DKM Sykanol DKM extra (R) M) sec. Alkanesulfonate, commercial product Hostapur SAS 30 (R) N) alkylbenzenesulfonate, Trade pro Arlicon-Paste (R) O) fatty alcohol polyglycol ether, Han product Eumulgin 1092 AL (R) P) Ethoxylated fatty amine, commercial Araphen K 100 (R) Q) Cetyl-trimethyl-ammonium chloride product Dehyquart A (R) R) coconut fatty acid poly-diethanolam product Comperlan PDR S) Na-α-sulfo-hydrogenated palmke methyl ester salt Release agent T) Na- sulfo-hydr. Tallow fatty acid methyl ester salt U) disodium salt of α-sulfo-hydr. Pa acid V) disodium salt deroC-sulfo-hydr. Tallow fatty acid W) disodium salt of α-sulfo-pa X) disodium salt deroC-sulfo-hydr. Coconut fatty acid Y) disodium salt the α-sulfo-hyd fatty acid Z) disodium salt of the α-sulfo-hydr.

acid #) disodium salt of the α-sulfo-behen @ #) di-magnesium salt the α-sulfo-lmy @ #) di-isopropylamine salt of an α-sulfo @ mixture obtained by ozonated @ C15-18-α-olefins from Parafi @ and subsequent direct sulfonation #) Di-ammonium salt of an α-sulfoca mixture, obtained by direct sulfonation oxidation of the C10-18 dermal fatty acids.

#) Di-triethanolamine salt of α-sulfo-stea @ ß) Na-α-sulfo-hydr. Palm kernel fatty acid me @ salt with a disalt content of 15% £) disodium salt derM -sulfo-hydr. Palm kernel fatty acid with a content of Naα-sulfo- @ kernfatty acid methyl ester salt of lo%.

Table I Demolding tests on cast polyurethanes Release agent mixture a) mixture b) # mixture c) A good good good B good good good C bad bad D bad bad E bad bad F bad bad G bad bad H satisfactory satisfactory good I satisfactorily satisfactorily good - K bad L - very moderate M # satisfactory satisfactory satisfactory - good Good N bad o bad bad P - bad bad bad bad R bad bad S bad bad T bad bad U very good very good very good V very good very good very good W very good very good very good X good - very very good good - very good Good y. good - very very good very good Well Z # very good very good very good good good very good E good - very good - very very good good Good Release agent # Mixture a) Mixture b) Mixture c) very good very good very good good - very very good very good ml good good - very good - very good good Good good - very very good good - very # good Good good - very very good very good Well 2) In a further experiment, a "self-adhesive" styrene-butadiene rubber mixture of the following composition was used to investigate the release effect.

loo parts by weight of styrene-butadiene rubber SBR 1500 1.5 liters of stearic acid 5 "I1 zinc oxide 1" "Phenyl-α-naphthylamine 30 II precipitated silica 2" "Aromatic Oil 2" n Black lead 1.8 n 1? secondary amine 6 "" 1: 1 mixture precipitated silica and resorcinol 1.6 tf II hexamethylenetetramine 1 "" N-cyclohexyl-2-benzhiazylsulfenamide 1 n "di-o-tolylguanidine 1.8" n sulfur This mixture is specially adjusted to that they do without the use of rubber-to-metal binders Metal surfaces adheres and vulcanized in a conventional press vulcanization for 10 minutes at 1530 C.

Before vulcanization, the steel vulcanization mold became intense cleaned and with a 0.5% solution already listed in Example 1 release agent coated once. In the form prepared in this way, plates were made from above said mixture, without repeated treatment of the mold with release agents, until there were significant demolding difficulties. The number of pressings is therefore a measure of the productivity and effectiveness of the release agents used.

The results are shown in Table II below.

Table II Release agent Number of pressings A 2 D 1 E 1 F 1 G 1 H 1 1 2 M 1 o 1 P 2 R 1 S 1 T 1 U 6 V 8 Release agent Number of pressings W 6 x 4 Y 6 Z 6 6th 7r 5 according to 4 4th 8th 4th # 8th 3) Non-post-cure silicone rubber.

Newer types of silicone rubber, in contrast to the previously common ones Types after vulcanization in the press no additional post-curing in Must be exposed to circulating air to achieve good mechanical properties, hard quite strongly on the walls of the vulcanization mold and consequently result easy demolding difficulties after vulcanization.

The following silicone rubber mixtures were used for the tests.

a) loo parts by weight of R 3027 AL from Wacker-Chemie GmbH 1.2 t? Dicumyl peroxide b) loo It "R 3035 AL from Wacker-Chemie GmbH 1,2" "dicumyl peroxide Vulcanization was stirred for 15 minutes at 1550 C, As a mold release agent was the inventive V) disodium salt dero - sulfo-hydr. Tallow fatty acid (see example 1) and, for comparison, a commercially available silicone drug Tegosil-Spray extra (R) used.

It was found that a proper demolding in each case a single application of an 0.5% solution of the release agent according to the invention V) (see Example 1) was sufficient, while the silicone release agent was significantly higher Layer thickness than usual had to be applied.

4) A very sticky, soft natural rubber mixture was used for the following experiment the following composition is used.

loo parts by weight of natural rubber tE-RSS 1 lo zinc oxide 2 "" n stearic acid 1 "phenyl - # - naphthylamine 2 spruce tar 25" EPC carbon black 0.33 II zinc dimethyl dithiocarbamate 0.58 "1I dibenzothiazyl disulfide 2.75 sulfur First, mix plates according to the above recipe in 0.5% solutions of the various release agents immersed in the list in example 1. Two plates treated in this way were each after Evaporation of the water placed on top of each other and loaded with weights, so that a pressure of approx. 200 g / cm2 resulted. After 24 hours it was checked whether a slight separation of the two plates was possible.

Then the two plates were put back on top of each other and one Vulcanization press pressed for 10 minutes at 153 ° C. the vulcanizate was then investigated whether both plates were during the vulcanization process have been flawlessly welded to one another, i.e. the separating effect of the applied Release agent was canceled again.

The results of the experiment are given in Table III below.

Table III Layer release agent Layer separation Welding D # moderately very good E moderately very good F moderately very good G moderately very good H moderately very good I moderate, very good M moderately very good O moderately very good R moderately very good S moderate - good very good T moderate - good very good U very good very good V very good very good W very good very good very good very good good-very good very good very good very good The advantage resulting from the use according to the invention of the disalts of ob-sulfocarboxylic acids with a chain length of 8-26 carbon atoms as a release agent for elastomers is that both excellent separation between layers and molds can be achieved without later sticking of the vulcanizate into one composite article made difficult or the subsequent application of a paint is adversely affected.

Claims (5)

Claims 1) Use of disalts from oC sulfocarboxylic acids of one chain length of 8 - 26 carbon atoms and alkali metals, magnesium, ammonium, short-chain aliphatic amines or short-chain aliphatic alkanolamines as release agents for natural and synthetic elastomers. 2) Use of di-sodium or di-potassium salts of al-sulfocarboxylic acids according to claim 1. 3) Use of disodium or disodium salts of C - sulfocarboxylic acids with a chain length of 12-18 carbon atoms according to claims 1 and 2. 4) Use of disalts of sulfocarboxylic acids according to claim 1 - 3 in 0.1 - 10%, preferably 0.2-2%, aqueous solution. 5) Use of disalts derM - sulfocarboxylic acids according to claim 1 - 4 with a content of ester salts of oC - sulfocarboxylic acids.