JP2002527540A - Redox polymerization method - Google Patents

Abstract

  (57) [Summary] Including a step of reacting a polymerization initiator, a reducing agent and a polymerizable substance with each other, provided that the polymerization initiator and the reducing agent are reacted with each other in an emulsion polymerization method wherein the polymerization initiator is not a hydroperoxide. The free radical moiety then initiates the polymerization of the polymerizable material, where the process is performed at an initial low starting temperature, and then the temperature is increased to increase the final A method comprising following a temperature profile up to a predetermined polymerization temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an emulsion polymerization method, a polymer obtainable by the method, and a method for using the same.

[0002]

[Prior art]

The production of aqueous resins, for example by emulsion polymerization techniques, is performed thermally using inorganic persulfates. A problem with thermal polymerization is process time, which results in less than the desired reactor output.

[0003]

[Problems to be solved by the invention]

It is an object of the present invention to provide another polymerization method aimed at improving the process time.

[0004]

[Means for Solving the Problems]

 A first aspect of the present invention provides a method according to claim 1.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

Since the polymerization process according to the present invention provides the free radical initiator moiety by a redox reaction instead of by thermal decomposition, the polymerization can be carried out by so-called "cold start", which reduces the process time and reduces With an increase in reactor output.

Redox polymerization is performed using t-butyl hydroperoxide “Trigonox A-W70”
Is known. However, the inventors have shown that redox polymerization using other organic peroxides provides unexpectedly good results.

We have shown that polymerization can be initiated at relatively low initial temperatures. This means that the polymerization time can be reduced by using the method of the present invention, due to the relatively long "heat-up" time required for thermal polymerization.

We further show that the process according to the invention makes it possible to obtain polymers with a very low residual monomer content, while for thermal polymerizations the amount of initiator used is reduced. Showed that you get.

Good results have been achieved under the conditions defined in claims 2-6. The polymerization initiator is most preferably a substantially water-insoluble initiator as defined in claim 7 or 8. This is because these water-insoluble initiators give unexpectedly high efficiencies in the polymerization.

[0010] This higher efficiency results in shorter polymerization times and polymer resins with improved properties. The higher efficiency of the organic peroxide is represented by a lower level of residual monomers and a lower molecular weight (Mw / Mn) of the resulting polymer.

Furthermore, the conductivity of the resin initiated by the organic peroxide / redox system is lower than the corresponding resin initiated by the persulfate.

[0012] The redox reducing agent is selected from the following group. That is, sodium formaldehyde sulfoxylate (SFS), sodium bisulfite, ascorbic acid (vitamin C), aldehydes such as glutaraldehyde, sodium metabisulfite, sodium dithionate and sugars, most preferably the reducing agent is sodium Formaldehyde sulfoxide.

[0013] The polymerizable substance is preferably selected from the following group: That is, acrylonitrile, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, dimethylamino acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl Methacrylate, stearic acid methacrylate, dimethylamino methacrylate, allyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, glycidyl acrylate, versatic acid ) Vinyl Esters, styrene, p-methylstyrene, vinyl acetate, α-methylstyrene, most preferably the polymerizable material is vinyl acetate and / or
Or a vinyl ester of versatic acid.

Further preferred process conditions are detailed in claims 11 to 15.

The polymerization is carried out, for example, using a mixture of anionic and nonionic surfactants, such as Witcon.
This is done in a normal emulsification in ate (sodium α-olefin sulfonate) and Syntopon (ethoxylated nonylphenol). However, other emulsifiers or mixtures are also possible.

[0016] The emulsifier solution is preferably a mixture of nonionic and anionic emulsifiers,
Most preferably, it is selected from the group consisting essentially of: Long-chain fatty acid carboxylate (ionic), alkylbenzene sulfonate (ionic), alkyl sulfate (ionic), dialkylsulfosuccinate (ionic), ethoxylated alcohol (nonionic), ethoxylated alkylphenol (nonionic) ), Ethoxylated amines or amides (non-ionic)

A second aspect of the present invention provides a polymer obtainable according to the present method.

[0018]

【Example】

Next, the present invention is further described by the following examples. Examples 1 to 6 are comparative examples, and Examples 7 to 12 are examples according to the present invention using a redox system.
Examples 3, 4, 6, 8-12 were subjected to a temperature profile that increased from the initial temperature to the final temperature. That is, it was subjected to a so-called “low temperature start”. Example 7 was performed at a constant temperature.

Preparation Procedure The polymerization in all examples was carried out under nitrogen in a 0.25 liter glass reactor with stirrer. First, the nuclei were prepared by adding 10% of the reactive components at the polymerization temperature.

The production of the nucleus was carried out as follows. That is, an emulsifier solution (NaAc / HAc) treated with a buffer (NaAc / HAc) prepared using oxygen-free deionized water in a reactor.
Witconate / Syntopon). At the polymerization temperature, soap (Witconate and Syntop
On), 10% of the pre-emulsion, monomers and, in the case of the redox system according to the invention, also a reducing agent and a catalyst were added. In addition, initiator solutions or pre-emulsions were added to achieve precise dosing control of the initiator.

After a polymerization time of 30 minutes, the remaining monomer, pre-emulsion and initiator solutions were charged in 2.5 hours. In Examples 3, 4, 6, 8 to 12, the temperature was increased to the final temperature in the same time according to the temperature profile. The final temperature was maintained for one hour.

The composition of the buffered soap solution used was as follows: NaAC. Trihydrate 0.25 g (sodium acetate) HAc 0.11 g (acetic acid) H ₂ O 30.3 g Witconate 0.38 g (soap) Syntopon 0.38 g (soap)

Example 1 Thermal System During the polymerization, the temperature was maintained at 70 ° C. The composition of the pre-emulsion used was as follows. Witconate 1.28 g Syntopon 1.28 g H ₂ O 34.43 g Vac (vinyl acetate) 52.5 g (monomer) VEOVA (vinyl ester of versatate) 22.5 g (monomer)

The initiator solution consisted of 4.18 mmol of ammonium / sodium or potassium persulfate in 25 g of H ₂ O. The total process time, including the time required to raise the reactor contents to 70 ° C. prior to polymerization, reached 5.5 hours.

Examples 2, 5 and 7 The temperatures were maintained at 70 ° C. (Examples 2 and 5) and 20 ° C. (Example 7), respectively.
The composition of the pre-emulsion used was as follows. Witconate 1.28g Syntopon 1.28g H ₂ O 34.43g of over 1.04 to 4.18 mmol Vac (vinyl acetate) As mentioned in the oxide Example 52.5 g (monomer) VEOVA (versatic acid 22 0.5g (monomer) vinyl ester)

The reducing agent SFS (sodium formaldehyde sulfoxide: 0.65 g) and the catalyst (FeSO ₄ : 16.7 mg) were dissolved in 25 g of H ₂ O. Total process time was 4 hours.

The polymerization temperature was maintained at 20 ° C. for the first 30 minutes to produce Examples 3, 4, 6, 8-12 nuclei. Then, according to the temperature profile, the temperature was increased by 20 ° C./hour to 70 ° C. It should be noted that other starting temperatures and temperature programs can be used for initiating the polymerization or for initiating and completing the polymerization. In all examples, residual monomers were determined by gas chromatography (GC). The molecular weight of the polymer produced was determined by gel permeation chromatography (GPC) using polystyrene for calibration. Conversion / solids content was determined by standard procedures. Viscosity was determined using a Brookfield digital viscometer. Table 1 shows the results.

Examples 13 to 24 Preparation Procedure The polymerizations in all examples were carried out under nitrogen in a 0.25 liter glass reactor equipped with a stirrer. The nuclei were first prepared by adding 10% of the reactive components at the polymerization temperature. The production of the nuclei was performed as follows. That is, the reactor was filled with an emulsifier solution (sodium lauryl sulfate in water) prepared using deionized water without oxygen. At the starting polymerization temperature, 10% of the soap-containing pre-emulsion, monomers and, in the case of a redox system, also a reducing agent and a catalyst were added. In addition, initiator solutions or pre-emulsions were added to achieve precise dosing control of the initiator.

After a polymerization time of 30 minutes, the remaining monomer, pre-emulsion and initiator solutions were charged in 2.5 hours. The temperature was raised to the final temperature at the same time according to the temperature profile. The final temperature was maintained for one hour. The composition of the soap solution was as follows. 0.10 g sodium lauryl sulfate (emulsifier) 25.0 ml deionized water Pre-emulsion: 1.60 g sodium lauryl sulfate 30 ml deionized water 70 g monomer mixture (butyl acrylate / styrene / methacrylic acid = 6 /
4 / 0.1) (If not water-soluble, include initiator (1.04 meq)) Reducing agent SFS (0.16 g of sodium formaldehyde sulfoxylate) and catalyst (2.8 mg of FeSO ₄ ) in 10 ml of water Dissolved. Oxidizing agent: reducing agent: Fe molar ratio = 1: 1: 0.01 The results are shown in Tables 2 and 3.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

As a result reference, vinyl acetate using potassium persulfate at 70 ° C. and Veo
Va emulsion copolymerization was used (thermal conditions). As a result, it is understood that the amount of residual monomer is low with respect to the water-insoluble organic peroxide (peroxyester) under redox conditions. The efficiency of water-insoluble peroxyesters such as Trigonox C was much higher than water-soluble persulfates and hydroperoxides, so the loading was 20-40% of the first milliequivalent of the initiator used. Could be lowered. Due to the relatively low amounts of initiator and reducing agent, relatively high values for pH and relatively low values for conductivity were obtained.
The polymer produced had a molecular weight (Mw / Mn) comparable to that of the VeoVa / VAc reference copolymer. Peroxyesters such as Trigonox 21 gave high conversion of monomer at room temperature. The invention is not limited to the above description, but rather the rights required are determined by the following claims.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN , IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Malta, Anne Marique Netherlands , 6605 XS We Chen, De Meren 1729 F-term (reference) 4J011 AA03 AA05 AA08 AB02 DA01 DB12 KA02 KA04 KA10 KA11 KA12 KB02 KB05 KB08 KB21 KB22 KB29 4J015 CA06 CA07 CA08 CA09 CA14 CA15 4J038 CC021 CG1 CG031 CH121 CH171 CH201 JA66 KA03 LA02 MA08 MA10 4J040 DB031 DB071 DB081 DE021 DF011 DF021 DF031 DF081 DF091 JA03

Claims (16)

[Claims] Claims: 1. An emulsion polymerization method comprising reacting a polymerization initiator, a reducing agent and a polymerizable substance with each other, except that the polymerization initiator is not a hydroperoxide. Reacting to provide a free radical portion of the initiator, which then initiates the polymerization of the polymerizable material, where the process is performed at an initial low starting temperature, after which the temperature is reduced. Increasing the temperature profile to a final predetermined polymerization temperature. 2. The method according to claim 1, wherein the process is performed at an initial temperature of up to 70 ° C., for example at an initial temperature of up to 50 ° C., preferably up to 35 ° C. 3. The process according to claim 1, which is carried out at an initial temperature in the range from + 10 ° C. to 35 ° C., preferably in the range from 15 ° C. to 25 ° C. 4. The method according to claim 1, wherein the initial temperature is maintained for a predetermined time, for example, up to 2 hours, preferably up to 1 hour, most preferably up to 30 minutes.
The method described in the section. 5. Following the initial temperature holding period, the temperature is increased to the final polymerization temperature, preferably to a final polymerization temperature of at most 90 ° C., according to the temperature profile, and the final polymerization temperature is preferably 50 to 80 ° C. The method according to any one of claims 1 to 4, wherein the temperature is in the range of 70 ° C. 6. The method according to claim 5, wherein the initial temperature is increased gradually over a predetermined period of time, preferably by about 20 ° C. per hour. 7. An initiator comprising diisobutanoyl peroxide, cumyl peroxy neodecanoate, 2,4,4-trimethylpentyl-2-peroxy neodecanoate, t-amyl peroxy neodecanoate, Bis (4-t-butylcyclohexyl) peroxydicarbonate, bis (-ethylhexyl) peroxydicarbonate, t-butylperoxyneodecanoate, dibutylperoxydicarbonate, dicetylperoxydicarbonate, dimyristilper Oxydicarbonate, t-amylperoxypivalate, t-butylperoxypivalate, bis (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, didecanyl peroxide, 2,5 ″ -Screw (2-
(Ethylhexanoylperoxy) -2,5-dimethylhexane, t-amylperoxy-2-ethylhexanoate, dibenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Diethyl acetate, 1,4-bis (t-butylperoxycarbo) cyclohexane, t-butylperoxyisobutanoate, 1,1-bis (t-butylperoxy) -3,
3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxy-3,5-trimethylhexanoate, 2
, 2-bis (t-butylperoxy) butane, t-butylperoxyisopropyl carbonate, t-butylperoxy-2-ethylhexyl carbonate, t-
Butyl peroxyacetate, t-butyl peroxybenzoate, di-t-amyl peroxide, dicumyl peroxide, bis (t-butylperoxyisopropyl) benzene, 2,5-bis (t-butylperoxy) -2 From the group consisting essentially of 2,5-dimethylhexane, t-butylcumyl peroxide, 2,5-bis (t-butylperoxy) -2,5-dimethyl-3-hexyne and di-tert-butyl peroxide. 7. The method of claim 6, wherein the method is selected. 8. An initiator which is substantially water-insoluble and comprises aliphatic and aromatic peroxyesters, preferably t-butylperoxy-2.
-Ethylhexanoate (Trigonox 21), t-amylperoxy-2-ethylhexanoate, t-butylperoxybenzoate (Trigonox C), t-amylperoxybenzoate, t-butylperoxyacetate, t- Butylperoxy-3,5-trimethylhexanoate, t-butylperoxyisobutanoate, t-butylperoxydiethyl acetate, t-butylperoxypivalate; peroxycarbonate, preferably t-butylperoxy The method of claim 7, wherein the method is selected from the group consisting essentially of isopropyl carbonate (Trigonox BPIC), and t-butyl peroxy-2-ethylhexyl carbonate (Trigonox 117). 9. The method according to claim 9, wherein the reducing agent is sodium formaldehyde sulfoxylate (SF).
S), sodium bisulfite, ascorbic acid (vitamin C), an aldehyde such as glutaraldehyde, sodium metabisulfite, sodium dithionate and saccharides. The method described in the section. 10. The polymerizable substance is acrylonitrile, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, dimethylamino acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, Isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearic acid methacrylate, dimethylamino methacrylate, allyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide , Glycidyl acrylate, versatin 10. The method according to any one of the preceding claims, wherein the method is selected from the group consisting essentially of vinyl esters of acids, styrene, p-methylstyrene, vinyl acetate, [alpha] -methylstyrene. 11. The reaction is carried out in the presence of a catalyst, which is preferably a water-soluble salt derived from a transition metal, most preferably from Fe ²⁺ , Co ³⁺ , Cu ⁺ and Ce ^{3 +.} 11. The method according to any one of the preceding claims, wherein the method is selected from the group consisting essentially of: 12. An initiator and a reducing agent in a ratio of 10: 1 to 1: 5, preferably 4: 1 to 1
The method according to any of the preceding claims, wherein the method is provided in a ratio of 1: 2. 13. The process according to claim 1, wherein the catalyst: oxidant ratio is about 0 to 0.1 (based on mole). 14. A polymer obtainable according to the method according to claim 1. 15. The polymer of claim 14, wherein the polymer has one or more of the following characteristics: a conductivity of less than about 5, a low residual monomer content, and a particle size of less than about 220 nm, preferably less than 200 nm. 16. Use of a polymer according to claim 14 or 15 in a coating and / or adhesive.