JPH0120162B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a process for producing aqueous emulsions and latexes of sulfonated low unsaturated elastomers. In particular, the present invention relates to an improved method of inactivating or inhibiting elastomer cement sulfonation reactions to provide products that are relatively easily emulsifiable. Sulfonated ionomers of butyl rubber and ethylene-propylene-diene terpolymers are described, for example, in Canter, US Pat. No. 3,642,728, issued February 15, 1972. Latexes made from sulfonated butyl rubber are disclosed in U.S. Pat. Emulsify using an activator. U.S. Pat. No. 3,912,683 to O'Farrell, issued October 14, 1975, deals with the emulsification of neutralized sulfonated butyl rubber with anionic surfactants. U.S. Patent No. 1, issued September 17, 1974, by Overall et al.
No. 3,836,511 deals with the acyl sulfate sulfonation of these elastomers. In the aforementioned techniques for producing sulfonated elastomer latexes, significant amounts of alcohols such as n-propanol are required to inhibit or inactivate the sulfonation reaction. This inactivation step is absolutely necessary to provide an emulsifiable product which is further processed into a suitable latex. The amount of such alcohol used is on the order of 20-40% by weight based on the weight of the sulfonated elastomer cement. After removing the solvent, alcohol and excess water from the initial latex to form the final latex, extensive distillation and purification procedures are performed to separate the solvent, alcohol and water if these amounts of alcohol are present. Requires. If alcohols such as 1-octanol are used that have a sufficiently high boiling point that they are not removed during solvent stripping and concentration of the latex, these alcohols will remain as a component of the final latex and cause excessive coagulation and other effects in the final product. Causing instability problems. Other disadvantages of using alcohol depressants are:
This means that for every 100 parts of sulfonated elastomer present in the cement state, it is necessary to use fairly large amounts of emulsifier, for example 10 to 15 parts. It is known that alcohols have an adverse effect on the surfactant properties of anionic emulsifiers. In the present invention, many of the drawbacks caused by the use of alcohol deactivation systems for sulfonation reactions have been overcome by using organic epoxides containing at least one reactive oxirane functionality. Stoichiometric amounts of epoxides may be used to inactivate or inhibit the sulfonation reaction. According to the present invention, there is provided a method of making cements of sulfonated low unsaturated elastomers, such as sulfonated butyl rubber and sulfonated EPDM elastomers. The method includes (a) providing an elastomeric cement in a volatile hydrocarbon solvent, (b) sulfonating the elastomeric cement with a sulfuric acyl sulfonating agent, and (c) at least one reactive oxirane group, i.e.

The method includes the step of inactivating an organic epoxide having a stoichiometric amount using a stoichiometric amount. (d) forming an aqueous emulsion of the product in a neutralized state using an anionic surfactant emulsifier (the product being neutralized before or after emulsification with a weak base); A latex of sulfonated elastomer can be obtained by including a further step of removing excess water and solvent to obtain a stable latex emulsion. Further illustrating the invention is a stable latex emulsion produced by the method described above. As used herein, the term "butyl rubber" refers to about 0.5 to about 15 mole percent conjugated diene and
means a copolymer of isoolefin and conjugated diene containing 99.5% isoolefin. Examples of isoolefins that can be used in the production of butyl rubber include isobutylene, 2-methyl-1-propene,
These include 3-methyl-1-butene, 4-methyl-1-pentene and β-pinene. Examples of conjugated dienes are isoprene, butadiene, 2,3-dimethylbutadiene, chloroprene, piperylene, 2,5
-dimethylhexer-2,4-diene, cyclopentadiene, cyclohexadiene and methylchloropentadiene. The production of butyl rubber is described in U.S. Patent No. 2,356,128 and in Industrial and Engineering Chemistry by R. M.
Chemistry), Volume 32, Page 1283. The term "EPDM" is used in the sense of the definition as found in ASTM-D-1418-64 and refers to a terpolymer containing ethylene and propylene in the main chain and dienes in the side chains. Methods for making these terpolymers are described in US Pat. No. 3,280,082, British Patent No. 1,030,989 and French Patent No. 1,380,600. Preferred polymers are about 45 to about 80% by weight
of ethylene and about 2 to about 10 weight percent diene monomer, the remainder being propylene. The diene monomer is preferably a non-conjugated diene. Examples of these non-conjugated diene monomers that can be used in the terpolymer (EPDM) include hexadiene, dicyclopentadiene, ethylidene norbornene, methylene norbornene, propylidene norbornene, and methyltetrahydroindene. Typical EPDM has an ethylene content of approximately 56% by weight
and a monomer blend having a non-conjugated diene content of about 2.6% by weight and having a Mooney viscosity of about 90 at 100°C (212°C). As used herein, the term "cement" refers to butyl rubber or
Refers to a viscous solution of EPDM polymer. Preferred solvents are aromatic hydrocarbon solvents. Sulfonated cement usually has about 3000 to about 10000 cps
(12 rpm; 24°C). The viscosity of this cement before sulfonation is preferably between 3000 cps and 6000 cps, for example 4000 cps. Cement is first prepared by dissolving butyl rubber or EPDM in a suitable aliphatic or aromatic hydrocarbon or chlorinated hydrocarbon solvent. Examples of solvents include hexane, heptane, cyclohexane, dichloroethane, methylene chloride, carbon tetrachloride,
Examples include toluene, benzene, xylene, etc. Toluene is particularly suitable. Generally speaking, the solvent has a boiling point below about 125°C, preferably below the boiling point of water;
It is possible to form an azeotrope with a boiling point below that of water to facilitate solvent stripping when the final latex is produced. The initial concentration of the butyl rubber or EPDM polymer solution is generally about 5 to 50% by weight, preferably about 7 to 18% by weight.
Weight%. In the practice of this invention, sulfonation of the cement solution is carried out using a sulfuric acid acyl sulfonating agent.
Suitable sulfonating agents include acetyl sulfate, propionyl sulfate, butyryl sulfate, with particular preference being given to using acetyl sulfate. The acylsulfuric acid sulfonating agents used according to the invention are prepared by reacting monobasic acid anhydrides with sulfuric acid or by reacting monobasic organic acids with SO ₃ . Sulfonation of unsaturated elastomers is generally described in U.S. Pat.
Described in No. 3836511. Acyl sulfates can be prepared in a solvent, but are preferably prepared without added water, ie without solvent, by adding concentrated sulfuric acid to the corresponding acid anhydride. The acyl sulfate may be formed at a temperature of about -100°C to +50°C, more preferably -40 to +30°C, for example about 20°C. Preferably the acyl sulfate is prepared immediately before use. On-site manufacturing is appropriate. For example, it is produced by adding an acid anhydride to a polymer solution and then adding sulfuric acid. If the acyl sulfate is prepared in a solvent prior to use, the solvent concentration is approximately
0.5 to 25% by weight, more preferably 1 to 20% by weight, most preferably 10 to 20% by weight, for example 18
Weight%. Sulfonation of butyl rubber or EPDM cement can be carried out at any temperature. For example -100
It can be carried out at temperatures between 100°C and 100°C. Pressure is not a critical condition and can be adjusted to any degree. For example, sulfonation can be carried out at pressures as low as about 0.5 atmospheres to as high as 10 atmospheres or more. From an economical point of view, the most suitable conditions are temperatures between 15°C and 40°C and pressures near atmospheric. The sulfonation time will vary with the particular conditions selected so that the polymer is sulfonated to the desired degree of sulfonation. Generally, the sulfonation reaction is complete within seconds to hours after the reactants come into contact with each other. For sulfonation at about room temperature and atmospheric pressure, the contact time is about 5 seconds to about 25-30 minutes. The degree of sulfonation of the polymers of the present invention is approximately 0.08
mol % to about 15 mol %. Preferably, the degree of sulfonation is from about 0.08 to about 10 mol%, more preferably from about 0.1 to about 8 mol%, and most preferably from about 0.2 to about 8 mol%. After carrying out the sulfonation reaction, the sulfonated cement is inactivated or suppressed using an organic epoxide containing at least one reactive oxirane group.
Organic epoxide compounds are generally suitable for practicing the present invention if they contain at least one oxirane group capable of reacting with the _-SO3H group. Suitable epoxides include aliphatic, cycloaliphatic and aromatic epoxides. These epoxides may also contain other functional substituents such as ester groups, unsaturated bonds or chlorine and similar substituents that do not have an adverse effect on the inhibition process. Generally speaking, suitable epoxides have about 2 to 20 carbon atoms. Particularly useful in the practice of this invention are epoxides having 2 to 8 carbon atoms, such as ethylene oxide, propylene oxide, 1,2
- Epoxybutane, etc. Examples of other suitable epoxides include 3,4-epoxy-1-butene,
1,2,3,4-diepoxybutane, 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 1,2-epoxy-2-methylpropane, 1-chloro-2,3-epoxypropane, ethyl 2,3-epoxybutyrate, 1-allyloxy-2,3-epoxypropane, 2,3-epoxypropyl methacrylate, 1,2-epoxyethylbenzene (styrene oxide), alpha-methylstyrene oxide, and similar compounds including oxirane. There are compounds. Epoxide is a mixture of propylene oxide and toluene (the concentration of propylene oxide is about 20 to 30
% by weight), suitably in the form of a mixture using the same solvents used in the preparation of the cement elastomer. In the practice of this invention, at least an inactivating stoichiometric amount of epoxide is used. That is, the base is such that the number of moles of reactive oxirane groups present is equivalent to the number of moles of the sulfonating agent used. Generally speaking,
The molar ratio of epoxide to sulfonating agent based on the number of moles of oxirane groups is about 1:1 to 10:1. Thus, relatively small amounts of epoxide are required to inactivate the sulfonation reaction. In order to further obtain a latex emulsion according to the method, the sulfonated, inactivated, low unsaturated elastomer is emulsified in neutralized form in water.
The neutralization step may be before or after emulsion production.
It is generally preferred to first emulsify the product and then neutralize it. As neutralizing agents, organic amines or weak bases such as ammonium hydroxide are used. Lower alkyl primary amines and aromatic primary amines such as ethylamine, propylamine, butylamine, phenylamine, and the like are particularly useful. Other substituted organic amines are also useful, including secondary and tertiary amines. Examples of neutralizing agents include diethylamine, triethylamine, and those having substituents such as hydroxyl, chloro, carbonyl, ether, thioether, nitroso, and the like. As used herein, the term "weak base" applies to ammonium hydroxide and organic amines with a pKb greater than 3.0. The final latex is then treated with a strong base to increase the ionic bonding of the film cast from the latex. The term "strong base" means that the pKb value is
Used for metal compounds and organic amines smaller than 3.0. For example, sodium, potassium, barium and calcium hydroxides, alkoxides,
carbonates or amine compounds such as tetraorganoammonium hydroxide, tetramethylammonium hydroxide or trimethylbenzylammonium hydroxide. Latex emulsions are prepared by mixing approximately equal amounts of inert cement, in neutralized or unneutralized form, and water containing appropriate amounts of surfactants or emulsifiers. An advantage of the present invention is that emulsifiers are effective in producing stable oil-in-water emulsions in very small amounts. To date, the amount of emulsifier required to produce latex emulsions from alcohol-inhibited sulfonated elastomeric cement has been 10 parts per 100 parts of elastomer present in the sulfonated cement solution.
It was about 15 copies. In the present invention, effective emulsions and dispersions are obtained by using about 3 to 6 parts of anionic surfactant per 100 parts of elastomer present in the cement solution. Anionic emulsifiers are used in the preparation of the emulsion compositions of the present invention. Particularly preferred are the sodium, potassium and ammonium salts of sulfated ethoxyalkanols and alkylphenols. For example, C ₈ to C ₂₀ alkanols and alkylphenols, where the alkyl moiety has 8 to 12 carbon atoms, and the alkanols and alkylphenols contain about 1 to 10 moles of ethylene oxide. Sodium, potassium or ammonium sulfates derived from nonylphenol containing 4 moles of ethylene oxide are particularly useful in the practice of this invention. Other anionic surfactants and solubilizing groups such as C ₈ to C ₁₈ alkyl sodium and potassium sulfates, sodium alkyl glyceryl ether sulfonates, sulfonated aliphatic ester salts, etc.
Similar anionic surfactants such as SO ₄ H or -SO ₃ H may also be used, although they are less preferred. Other anionic surfactants that may be used are sodium, potassium or ammonium salts of fatty acids containing about 8 to 24 carbon atoms, preferably about 10 to 20 carbon atoms. Fatty acids can be obtained from natural sources such as coconut oil fatty acids, soybean oil fatty acids, tall oil fatty acids, rosin acids and hydrogenated rosin acids, or they can be synthesized, for example, by oxidation of petroleum fractions. Examples of such fatty acid carboxylate salts include sodium stearate,
Examples include sodium oleate, sodium palmitate, and potassium ricinoleate. After a latex emulsion is produced by mixing the ingredients by simple stirring such as manual stirring, the ingredients are further sufficiently stirred using a homogenizer or the like to reduce the particle size and further sufficiently disperse the particles. Excess water and aromatic solvents are then removed from the raw emulsion under vacuum to give a solids content of about 20 to 70% by weight, preferably 40 to 65%, such as 60% (the remainder being substantially water). Obtain the final latex. The final latex produced according to the invention is characterized by excellent tensile properties. It is useful as a binder in nonwovens, as an adhesive in paper coating operations, and as overdips in highly unsaturated rubber parts. The invention is further illustrated by the following examples. Example 1 Acetyl sulfate was prepared by dropping 11.0 ml of sulfuric acid into 37.7 ml of acetic anhydride while cooling the acetic anhydride in an ice bath. The mixture was stirred for 1 hour. Butyl rubber cement was prepared by dissolving EXXON BUTYL 268 in toluene to prepare a 16% by weight solution. Exonbutyl 268 is a copolymer of isobutylene (98.5 mol%) and isoprene (1.5 mol%), with a viscosity average molecular weight of 450,000 and a Mooney viscosity (ML1+3 at 127°C (260〓)) of 55.
To 625 g of this cement (including 100 g of butyl rubber) was added 6.47 ml of acetyl sulfate prepared previously. The mixture was stirred for 1 hour and then 2.5g propylene oxide mixed with 10g toluene was added.
A sample of the cement was removed and the sample was neutralized with ethylamine and precipitated with acetone. The sample was dried in a vacuum oven at 50°C overnight and then analyzed.
It was found to contain % sulfur by weight. 300 g of sulfonation-inhibiting cement was treated with sodium sulfate derived from nonylphenol to which 4 moles of ethylene oxide had been added.
Water containing 10 g of AlipalCo-433 (29.7% active surfactant by weight)
Added to 300g. The mixture was homogenized, neutralized with 5 g of ammonium hydroxide, and excess water and toluene were removed under vacuum using a rotary evaporator to produce a latex with 55% solids by weight. To evaluate the stability of the product, a sample of this latex at 40% solids was sheared in a Hamilton-Beach mixer at a speed of 19000 rpm for 30 minutes while heating to 82°C (180°). The coagulum reached 24% by weight. A sample of the final latex prepared as described above was adjusted to pH 9.5 with sodium hydroxide. A film was cast from the latex and dried overnight at room temperature. It was further dried in an oven at 77°C (170°C) for 4 hours, and then vacuum-dried at 50°C all day and night. The film had the following tensile properties: Strength at 100% elongation 6Kg/cm ² (85psi) Strength at 500% elongation 14Kg/cm ² (200psi) Tensile strength 190Kg/cm ² (2700psi) Elongation at break 1040% Example 2 This example is Figure 2 shows the effect of varying degrees of inhibition of propylene oxide on latex formation. A series of experiments were performed with varying amounts of propylene oxide. In each experiment, 100 g of cement containing butyl rubber was sulfonated with 6.5 ml (24 mmol) of acetyl sulfate using the procedure and materials described in Example 1. The sulfonated cement was suppressed with various amounts of propylene oxide as shown in Table 1. Each inhibiting cement (300 g) was added to a solution of 10 g of "Aliparco 433" as described in Example 1 in 300 g of water.

Table: Example 3 This example demonstrates the use of relatively small amounts of emulsifier. Example 1 Inhibited Sulfonated Cement 300
A latex was prepared by adding 4 parts of Aliparco 433 (6.7 g of 29.7% active material) in 300 g of distilled water. This is 4 parts of emulsifier for every 100 parts of elastomer present in the cement solution. Oil-in-water emulsions were easily formed. Add this emulsion to an Effenback mixer (Effenback mixer).
HomoMixer), raise the turning device plate and apply 40 volts for 3 minutes, raise the turning device plate and apply 110 volts for 3 minutes,
Then, the converter plate was closed and homogenization was easily carried out in 5 minutes at 110 volts. Example 4 Acetyl sulfate was prepared by dropping 11.0 ml of sulfuric acid into 37.7 ml of acetic anhydride while cooling the acetic anhydride in an ice bath. The mixture was stirred for 1 hour. The ethylene content is 51% by weight, the ethylidene norbornene content is 9% by weight, and the Mooney viscosity is 127°C in toluene.
By dissolving 50 EPDM at (260〓)
EPDM elastomer cement was prepared.
EPDM elastomer concentration was 10% by weight.
4.7 for 1000g of this cement (100g of elastomer)
ml of acetyl sulfate was added. The cement immediately turned dark brown and was stirred for 1 hour. Suppression was achieved with 2.5 g of propylene oxide dissolved in 10 ml of toluene. The cement changed to its original amber color within about 5 minutes. The mixture was stirred for an additional hour and a half. Sulfonated and suppressed cement (500g) with 500g of distilled water and "Aliparco 433" (27.4% active)
10.9 g. This corresponds to 6 parts of emulsifier per 100 parts of elastomer present in solution. Oil-in-water emulsions were easily formed. This emulsion was mixed with a converter plate using an F-enbag homo mixer.
40 volts for 5 minutes, turning device plate up and 110 volts for 5 minutes, and turning device plate lowered and 110 volts for 5 minutes.
Homogenized in minutes. Sodium hydroxide (5g in 10ml water) was added. The resulting latex had an average particle size of 1 micron. The latex has excellent mechanical stability at high temperatures and has only 0.36% coagulum after heating to 82°C (180°C) and shearing in a Hamilton-Beech mixer for 30 minutes at a rate of 19,000 cycles/min. Ta. Toluene and excess water were vacuum removed from the emulsion using a rotary evaporator to yield a latex with 36.6% solids. This latex had excellent mechanical stability, giving only 0.3% coagulum when stirred for 30 minutes at room temperature in a Hamilton-Beech mixer at a speed of 19000 rpm. A film was cast from the final latex. After drying the film had the following tensile properties: Strength at 100% elongation 8Kg/cm ² (115psi) Strength at 500% elongation 12Kg/cm ² (170psi) Tensile strength 54Kg/cm ² (775psi) Elongation at break 700% Example 5 This example is Indicates the use of ethylene oxide. Add 11.0 ml of sulfuric acid to 37.7 ml of acetic anhydride while cooling in an ice bath.
Acetyl sulfate was prepared by dropwise addition to ml of acetic anhydride. The mixture was stirred for 1 hour. Butyl rubber cement was prepared by dissolving Exontil 268 in toluene. Butyl rubber was 16% by weight. 625g of this cement
(100 g of rubber) was added 6.5 g of acetyl sulfate prepared as described above. This mixture was stirred for 1.5 hours. Ethylene oxide (3 ml, 2.6 g) was added to suppress the sulfonation reaction. A sample was removed and neutralized with ethylamine. The rubber was precipitated with acetone, dried in a vacuum oven, and analyzed for sulfur. The result was 0.7% by weight of sulfur. Cement suppressed with ethylene oxide (600g)
was mixed with 600 g of distilled water containing 21.9 g of "Aliparco 433" (27.4% active). This corresponds to 6 parts of emulsifier per 100 parts of elastomer present in solution. Add this emulsion to a converting device using an F-enbag homo mixer.
Homogenization was carried out for 3 minutes at 40 volts, 3 minutes at 110 volts with the turning device turned up, and 5 minutes at 110 volts with the turning device turned down. Ammonium hydroxide (28
% by weight) was added. Remove toluene and excess water using a rotary evaporator and reduce to 52.7
A latex with weight percent solids was obtained. The average particle size of the latex was <1 micron. Latex is made in a Hamilton-Beach mixer at 19,000 rpm.
It had only 0.0002% coagulum when sheared for 30 minutes at a speed of . Comparative Example This is a comparative example showing that higher alcohols are unsuitable as inhibitors for sulfonation of low unsaturated elastomers, which are raw materials for preparing latexes. Acetyl sulfate was prepared by dropping 11.0 ml of sulfuric acid into 37.7 ml of acetic anhydride while cooling the acetic anhydride in an ice bath. The mixture was stirred for 1 hour. Butyl rubber cement was prepared by dissolving Exon Butyl 268 in toluene. Butyl rubber was 16% by weight. 313g cement (rubber)
50 g) of acetyl sulfate prepared as above.
g was added. The mixture was stirred for 1.5 hours. 1-
Add octanol (31g, boiling point 194℃) to about 1/2
Stir for hours. Sulfonated cement inhibited with 1-octanol (345 g) was slowly added to a mixture of 345 g water, 31 g 1-octanol, and 27.4 g Aliparco 433 (27.4% active). This mixture easily formed a raw emulsion. Raise the conversion device plate with the F-enback home mixer and connect it to 3 with 40 volts.
Homogenization was carried out for 3 minutes at 110 volts with the turning device plate raised, and for 3 minutes at 110 volts with the turning device plate lowered. Ammonium hydroxide (28% solution 5
g) was added. Excess toluene and water were removed by stripping under vacuum using a rotary evaporator. The emulsion solidified at approximately 21% solids.

Claims (1)

[Claims] 1. A method for producing a cement of a sulfonated and inactivated low unsaturated elastomer of butyl rubber or EPDM, comprising: (a) providing a cement of an elastomer and a volatile solvent; (b) A method comprising the steps of: sulfonating an elastomeric cement with an acyl sulfate sulfonating agent; and (c) inactivating the sulfonated cement with at least a stoichiometric amount of an organic epoxide containing at least one reactive oxirane group. 2. The method of claim 1 further comprising the step of neutralizing the inert sulfonated cement with a weak base. 3. A method according to claim 1 or 2, wherein the epoxide has 2 to 8 carbon atoms. 4. In the method described in claim 3,
A method in which the epoxide is propylene oxide or ethylene oxide. 5. The method according to any one of claims 1 to 4, wherein the ratio of the number of moles of epoxide to the number of moles of sulfonating agent based on the number of moles of reactive oxirane group is 1:1. ~10:1
How to be. 6. The method according to any one of claims 2 to 5, wherein the weak base is ammonium hydroxide, ethylamine or triethylamine. 7. The method according to any one of claims 1 to 6, wherein the elastomer is butyl rubber. 8. The method according to any one of claims 1 to 6, wherein the elastomer is EPDM. 9. The method according to any one of claims 1 to 8, wherein the sulfonating agent is acetyl sulfate.