JPS61108629A - Recovery of polymer from polymer latex - Google Patents

Abstract

PURPOSE:To recover advantageously a polymer less corrosive to metal from a polymer latex, by bringing a polymer latex produced by polymerization in the presence of a specified emulsifier and having a specified composition into contact with an aqueous magnesium sulfate solution. CONSTITUTION:A latex of a polymer which is formed by polymerization in the presence of a substance having a group represented by -OSO3M, -COOM or -SO3M (wherein M is K or Na) in the molecule as an emulsifier (the basic structural units of this polymer contain at least 80wt% at least one unit selected from among an alkyl methacrylate, an alkyl acrylate, an aromatic vinyl compound, acrylonitrile, methacrylonitrile and butadiene) is brought into contact with 0.1-30wt% aqueous magnesium sulfate solution. Examples of the emulsifiers which can be used particularly preferably include sodium dioctylsulfosuccinate, sodium N-lauroylsarcosinate and potassium palmitate.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for recovering a polymer having excellent properties from a 1+7 mer latex of emulsion polymerization.

(B) Prior Art A polymer recovered from a polymer latex obtained by emulsion polymerization is sometimes added as a modifier to ABS resins, high-impact styrene resins, vinyl chloride resins, and methacrylic resins. It is a widely known fact that impact resistance, thermal properties, and moldability can be improved by adding a polymer recovered from a polymer latex produced by emulsion polymerization to the above-mentioned resin.

Various methods are known for recovering polymers from polymer latex, which is an emulsion polymer. For example, there are methods such as adding an acid such as hydrochloric acid or sulfuric acid to recover the polymer, spraying polymer latex in a high-temperature atmosphere, and adding inorganic salts such as aluminum chloride, sodium sulfate, aluminum sulfate, and calcium nitrate. be.

As mentioned above, these recovery methods are used to obtain useful polymer compositions to be added to ABS resins, high-impact styrene resins, vinyl chloride resins, and methacrylic resins. However, there are many proposals and documents regarding polymers to be added as modifiers.
This study concerns the structure of remer, and there are almost no cases where a method for recovering the polymer has been deeply studied.

For example, although it is known that polymers can be recovered by adding the above-mentioned inorganic salts, it is not known that the various properties of the recovered polymers vary greatly depending on the type of inorganic salts to be added. The same applies to the method of recovery by adding acids that are not present.

(, 9 Problems to be Solved by the Invention As a result of studying the effects on various properties of the recovered polymer by changing the type of substance added to recover the polymer, the following was found. It was.

In the case of an inorganic salt having a &-valent cation and a monovalent or divalent anion (e.g., NaC2, No□504),
In order to recover the polymer stably, it is necessary to add a large amount of inorganic salt. Furthermore, when the obtained polymer is added to methacrylic resin or the like, hot water whitening properties deteriorate.

b. In the case of inorganic salts containing chlorine ions, metals may be released, which may cause problems in the manufacturing process.

In the case of inorganic salts with C0 aluminum ions, the recovered polymer is colored. The same applies to inorganic salts having nitrate groups.

d. When sulfuric acid is used, the coloring of the recovered polymer is good, but the ABS resin to which this polymer is added has a lot of mold deposits during molding, the surface gloss is reduced, and the appearance of the molded product is poor.

Based on the above study results, we are working hard to find a method for recovering polymers that can be recovered with a relatively small amount of addition, have low metal corrosiveness, and do not reduce the properties of the blended resin when added to other resins. As a result of repeated studies, we have developed a polymer that achieves the desired purpose by contacting a polymer latex with a specific composition polymerized using a substance with a specific structure as an emulsifier with an aqueous magnesium sulfate solution in a specific concentration range. The present invention was achieved by discovering that the following can be obtained.

B) Means for Solving the Problems The method of recovering a polymer from a polymer latex according to the present invention uses 10-8o3 in its molecules as an emulsifier.
A polymer polymerized using a substance having a group represented by M, -OSO3M, -5o3M (where M is K or Na), and the basic structural acid unit of the polymer is an alkyl methacrylate ester or an alkyl acrylate ester. , aromatic vinyl compound.

It is characterized in that a polymer latex containing 80% by weight or more of at least one unit of acrylonitrile, methacrylonitrile, or butadiene is brought into contact with an aqueous magnesium sulfate solution having a concentration of 0.1 to 30% by weight.

The most important feature of the present invention is that, as mentioned above, methacrylate is polymerized using a substance having groups represented by 10-8oM, -COOM, -803M (where M is 2 or Na) as an emulsifier in the molecule. Acid alkyl ester, acrylic acid alkyl ester, aromatic vinyl compound, acrylonitrile, methacrylate trile.

80 units of at least one type selected from Poutasier/
polymer latex containing at least 0.1 to 30% by weight;
The method is to contact an aqueous solution of magnesium sulfate with a concentration of - by weight.

The emulsifier used in the present invention is a type of anionic surfactant. Emulsifiers made of substances other than anionic surfactants such as cationic surfactants and nonionic surfactants are not suitable for the present invention.

Even if it is an anionic surfactant, a surfactant having a phosphate group is not suitable.

The emulsifier used here has 10-8o5M in the molecule.

-COOM, -80,M (where M is K or Na
). Among substances having these groups, dialkyl sulfosuccinic salts, long chain alkyl sulfate salts, alkylbenzene sulfonates, and long chain alkyls (and/or long chain alkenyls) having 8 to 20 carbon atoms are preferred. fatty acid salts, N-acyl sarcosinates, more preferably sodium nooctylsulfosuccinate, sodium N-lauroyl sarcosinate,
Potassium or sodium palmitate, potassium tallow fatty acid, potassium or sodium oleate, potassium laurate, and the like.

The polymer composition obtained by emulsion polymerization and its proportions are:
Although the optimum value cannot be determined uniquely because it varies depending on the type and purpose of other resins added, the basic structural units are methacrylic acid alkyl ester, acrylic acid alkyl ester, aromatic vinyl compound, acrylonitrile, etc. Tacrylonitrile.

It contains at least 80% by weight of at least one type of butadiene unit. Examples of methacrylic acid alkyl esters include methyl methacrylate, ethyl methacrylate, and cyclohexyl methacrylate; examples of acrylic acid alkyl esters include methyl acrylate, ethyl acrylate,
Butyl acrylate.

Examples of the aromatic vinyl compound include 2-ethylhexyl acrylate, and styrene, vinyltoluene, α-methylstyrene, and the like. Unit 8 above
Examples of other units of 20% by weight or less constituting the polymer together with 0% by weight or more include methacrylic acid, acrylic acid, hydroxyethyl methacrylate, etc., as well as ethylene glycol dimethacrylate, divinylpenzea, L, 4-ff.
Rangelicol diacrylate, allyl methacrylate, triallyl cyanurate, allyl cinnamate.

Examples include polyfunctional monomers such as allyl sorbate, diallyl maleate, diallyl phthalate, triallyl trimellitate, and diallyl phthalate.

Emulsion polymerization is carried out in the presence of the emulsifier described above, using any monomer composition within the range that allows the formation of the polymer structural units described above.

The method of initiating polymerization is not particularly limited, but examples of radical polymerization initiators include peroxides such as benzoyl peroxide, cumene hydroperoxide, and hydrogen peroxide;
A redox initiator consisting of an azo compound such as azobisisobutyronitrile, a persulfate compound such as ammonium persulfate or potassium persulfate, a perchlorate compound, a perborate compound, or a combination of a peroxide and a reducing sulfoxy compound. can be given.

The monomer, polymerization initiator, etc. may be added by any known method such as a one-time addition method, a two-part addition method, a continuous addition method, a monomer addition method, or an emulsion addition method.

In addition, methods such as purging the reaction system with nitrogen to make the reaction proceed smoothly, raising the temperature of the reaction system after the reaction is completed to remove residual monomers, and adding special catalysts are used. Good too.

In the operation of recovering the polymer from polymer latex, the concentration of the aqueous solution of magnesium sulfate used is 0.1 to
It is 30% by weight, more preferably 1 to 15% by weight. 0
．． If it is less than 1% by weight, the polymer may not be recovered stably, and if it exceeds 30% by weight, the cost will increase and the amount remaining in the recovery/IJ mother will increase, which are both undesirable.

Although it is preferable to use magnesium sulfate alone for recovery, it is fully possible to use it in combination with other substances, such as other inorganic salts or acids, if necessary.

The recovery operation may be performed by continuously bringing the individually prepared polymer latex and magnesium sulfate aqueous solution into contact with each other. On the other hand, it may be carried out batchwise.

The temperature of contact is not particularly limited, but is 30°C to 10°C.
A range of 0°C is preferred.

The polymer latex and the aqueous magnesium sulfate solution are brought into contact with each other, and the coagulated slurry polymer is washed with about 1 to 100 times as much water and dried under a temperature condition in the range of 50°C to 100°C. The obtained powdered polymer can be molded as is or used as a modifier for other resins.

Margin below (e) Effect of the invention According to the recovery method of the present invention in which a polymer latex prepared using an emulsifier having a specific structure and magnesium sulfate are brought into contact with each other, a relatively Only by adding a small amount of recovery agent, one remer can be recovered, and there is very little residual magnesium sulfate in the recovered polymer. (Even if a small amount of magnesium ion remains, it is thought that it may react with the anion group of the emulsifier to form a magnesium salt.For example, as can be seen from the fact that magnesium stearate itself is used as a heat stabilizer. , Generally, magnesium salts have excellent heat resistance;
It is thought that it does not have an adverse effect on the polymer itself. ) Therefore, the recovered polymer has low metal corrosiveness and a low degree of coloration. Therefore, the problems of corrosion of the equipment during the solidification process, corrosion of the molding equipment and coloring of the molded product when used as a molding material can be solved. In addition, when the recovered polymer is blended with other molding resins as a modifier, it may impart undesirable properties such as not only metal corrosion and coloring but also hot water whitening and mold adhesion. There aren't many.

(f) Examples The present invention will be specifically described below with reference to Examples. In the examples, "parts" and "chi" indicate parts by weight, respectively.

Example 1, j? Manufacture of remar latex (4) Internal volume 50A! First, the following raw materials 0) were put in various proportions into a stainless steel reaction vessel, and nitrogen was blown into the container while stirring to make it substantially free from the influence of oxygen.
The temperature was raised to 0° C., the following raw materials (b) were added, and polymerization was carried out for 2 hours to obtain a hard crosslinked resin latex.

(a) Raw material deionized water 500 parts Dercosinate LN'') (S-LN) 0.10 parts Boric acid 1.0 parts Sodium carbonate
0.1 part (b) Raw material deionized water 10 parts Potassium persulfate (KP S ) 0.
3 parts*1) N-lauroyl sarcosinate (Nikko Chemicals (Ryosha product)) The polymerization rate of MMA in this latex was 98.5%, and the particle size was 0.16 μm.

(B) The following sodium formaldehyde sulfoxylate (hereinafter referred to as Rongalite) is placed in the container containing an amount of hard crosslinked resin latex in an amount equivalent to 15 parts of the solid content in which the polymerization in (4) above has been substantially completed. ) and an aqueous solution of sarcosinate LN sarcosine) L N 0.2
Part Rongarit 0.3
Add 2 parts 10 parts deionized water;
After raising the temperature to 80°C, the following composition ratios: butyl acrylate (BA) so% styrene (ST) 18.5% allyl cinnamate 0.8% 1.3-butylene dimethacrylate 0.6% A mixture of 85 parts of an acrylic acid ester member mixture and 0.32 parts of tertiary butyl hydroperoxide (TBH) was added continuously over 150 minutes. After the addition was completed, polymerization was continued for an additional 3 hours to obtain a multi-layered acrylic elastomer latex containing the hard crosslinked resin (4) inside the particles.

The polymerization yields of BA and ST were 97 and 99, respectively.
．． 5% or more, and the particle size of the obtained latex is 0.
It was 26-0.28 μm.

(Production of multi-structure methacrylic resin composition [■] by polymerization of Q monomer mixture (Q) Add latex equivalent to 100 parts of solid content of multi-structure acrylic elastomer CII obtained in polymerization (2) above. After adding 0.25 parts of Zircosine-1LN and 10 parts of deionized water into the above-mentioned container and stirring, the following monomer mixture (Q) was added continuously over a period of 2.5 hours. Thereafter, for an additional 1 hour. Polymerization was continued to obtain a multilayer methacrylic resin composition [13] in latex form.
The polymerization yield of MA was 99.5% or more in all cases.

Monomer mixture (0 TBHO, 15 parts) This latex was coagulated, washed, and
After drying, a powder of a multi-structure methacrylic resin composition CID was obtained.

1.8 polymagnesium sulfate aqueous solution 1 in a stainless steel container
400 parts of the mixture was charged, the temperature was raised to 80°C with stirring, 700 parts of the latex prepared earlier was added continuously over 20 minutes, and then the internal temperature was raised to 95°C and held for 5 minutes. After cooling to room temperature, the polymer was separated and washed with deionized water to obtain a white creamy polymer, which was incubated at 70°C for 24 hours.
After drying for several hours, a white powdery polymer was obtained.

Next, a mixture of this powder 1875N and methacrylic resin (Acryvet vH; Mitsubishi Rayon (□□□ product) 3125.9
e) Newly manufactured by Nippon Steel, P-40-26AB-V type, L/
D = 26), and the cylinder temperature is 200~2
The pellets were melt-kneaded at 60° C. and a die temperature of 250° C. to obtain an impact-resistant methacrylic resin composition containing 25 units of multilayer acrylic elastic body [■].

This was injection molded under the following conditions, and the evaluation results shown in Table 1 were obtained from the obtained test pieces.

Injection molding machine: Nippon Steel Sukeya Co., Ltd., -17-65 type automatic injection molding machine with one set of screws Injection molding conditions: Cylinder temperature 250°C, injection pressure 700
Yu/cn? Test piece size: 110mX 110mX 2+m (thickness) 70cmX12.5-x6.2cm (thickness) Example-2, Comparative Examples-1 to 5 1.8cm of the recovery agent used in Example 1 Example-1 except that the magnesium sulfate aqueous solution was changed as shown in Table-1.
The results shown in Table 1 were obtained in exactly the same manner as in Example 1.

From the results in Table 1, it can be seen that the properties other than the desired properties vary greatly depending on the type of substance from which I remer is recovered from the polymer latex.

Example-3 Production of polymer latex (1) Styrene 2 to 9
1.3-butadiene 8-yield pyrubenzene hydrono-oxide 20J
'Beef fat fatty acid potassium 1001N-y
Sodium uroyldercosinate 30I
Sodium birophosphate 501 Ferrous sulfate 0.5 g Dextrose 30 Deionized water
20kl? Among the substances with the above composition ratio, 1
, 3-butadiene, the oxygen contained therein was replaced with nitrogen so that the polymerization reaction was not substantially inhibited. The material was then charged into a 401 autoclave and polymerized at 55°C for 10 hours.

(2), into the reaction vessel in which the polymerization was carried out, containing the latex containing 101 volts of polymer solid content of the styrene-butadiene copolymer latex polymerized in (1)
klil, sodium formaldehyde sulfoxylate 2 (1,N-sodium lauroyl sarcosinate 5O
Add N and raise the internal temperature to 75°C.

The following raw materials were continuously added and polymerized over 90 minutes.

Styrene 4klj Acrylonitrile 11 Tertiary) r Silmercaptan 21 Cumene hydroperoxide
After the addition of l 5 z was completed, the polymerization was continued for an additional 60 minutes, and the conversion rate of monotyrene and acrylonitrile was approximately 100%.

The resulting polymer latex contained 40% of styrenated phenol and 581% of styrenated phenol. Dilaurylthiodipropionate 44JF
,) Riphenylphosphite 581 was added, and the latex was poured into a stainless steel container containing 80 g of a 1.8'% magnesium sulfate aqueous solution, under stirring at a temperature of 50° C., continuously for 20 minutes. After that, the temperature was raised to an internal temperature of 90°C and held for 5 minutes.

After cooling to room temperature, the obtained slurry polymer was washed, dehydrated, and dried at 65° C. for 36 hours to obtain a white powder.

This powdered resin CI[-112,9)CP and styrene-bucrylonitrile polymer resin (Lytax≠330; Mitsui Higashi Pressure Co., Ltd. product) 7.1 kg, stearic acid monoglyceride 101 kg. Ultraviolet absorber (Tinuvin-P/Sanol LS770: Ciba-Geigy/Sankyo Co., Ltd. product) 20
．． 9/3011 in a Henschel mixer with a capacity of 201, and then heated at 210 to 230°C using a 30 m + φ twin-screw presser (Ikegai Tekko Co., Ltd. Hire PCM-3O).
It was pelletized at a temperature of 25 rpm. This pelletized resin was molded using a scree injection molding machine (Nippon Steel Fracture; Ankerperk V-17-65 type) at a cylinder temperature of 220°C and an injection pressure (dart pressure) of 50 kg.
/cm”, 110 x 110〆2 (thickness) W and 70 x 1
A test of 2.5 x 6.2 (thickness) W was prepared and the evaluation results shown in Table 2 were obtained.

As can be seen from these results, the composition using the polymer recovered by the method of the present invention exhibits excellent impact resistance, and has good mold adhesion, heat coloring properties, and mold corrosion resistance.

Table 2 Examples 4 to 7, Comparative Example 6 The emulsifiers potassium tallow fatty acid and sodium N-lauroyl sarcosinate and the magnesium sulfate used as the polymer recovery agent were changed to the substances and proportions shown in Narrow-3. The study was carried out in exactly the same manner as in Example 3 except for the following. The results are shown in Table 4. These results show that the intended purpose can be achieved by using the emulsifier specified by the present invention, and that the polymer recovered with substances other than magnesium sulfate can be used.

It can be seen that the physical properties are inferior.

Margin below

Claims (1)

[Claims] 1. As an emulsifier, -OSO_3M, -C in its molecule
It is a polymer polymerized using a substance having a group represented by OOM, -SO_3M (where M is K or Na), and the basic constituent units of the polymer are methacrylic acid alkyl ester, acrylic acid alkyl ester, aromatic A polymer characterized by contacting a polymer latex containing 80% by weight or more of at least one unit of a vinyl compound, acrylonitrile, methacrylonitrile, or butadiene with an aqueous magnesium sulfate solution having a concentration of 0.1 to 30% by weight. How to recover polymers from latex. 2. The emulsifier is a dialkyl sulfosuccinate salt,
The polymer latex according to claim 1, which is at least one substance selected from the group consisting of long-chain alkyl sulfate salts, alkylbenzene sulfonate salts, and long-chain alkyl (and/or long-chain alkenyl) fatty acid salts. How to recover polymers from. 3. A method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is an N-acyl sarcosinate. 4. Claim 1, wherein the emulsifier is a long-chain alkyl and/or long-chain alkenyl fatty acid salt having 8 to 20 carbon atoms.
A method for recovering a polymer from a polymer latex as described in Section 1. 5. The method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is sodium dioctyl sulfosuccinate. 6. A method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is sodium N-lauroyl sarcosinate. 7. The method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is a potassium salt or a sodium salt of palmitic acid. 8. The method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is potassium tallow fatty acid. 9. The method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is a potassium salt or a sodium salt of oleic acid. 10. A method for recovering a polymer from a polymer latex according to claim 1, wherein the emulsifier is potassium laurate.