JPH0250125B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for continuously producing a rubber-reinforced aromatic monovinyl resin having an excellent overall quality balance. For example, rubber-reinforced polystyrene is often used in parts of home appliances, but
Compared to ABS resin, it has the disadvantages of poor molded product surface gloss, low impact strength, and poor texture when colored, resulting in an unsatisfactory molded product appearance. Recently, due to the desire to reduce costs and reduce thickness, there has been an increasing demand from the market for the emergence of rubber-reinforced polystyrene, which has properties close to those of ABS resin. In addition, recent technological trends related to rubber-reinforced polystyrene manufacturing methods include continuous bulk polymerization, which is low in manufacturing costs and has excellent product stability.
Emphasis is placed on it from a down perspective. Although the present invention is inexpensive, it is expensive.
It has sufficient gloss, coloring properties, etc. to replace injection molded products, extrusion sheets, extrusion vacuum molded products, etc. made from ABS resin.
The present invention aims to provide a continuous method for producing a reinforced aromatic monovinyl resin having excellent impact strength and overall quality balance, particularly a continuous bulk polymerization method. [Conventional technology and its problems] Conventionally, a styrene monomer solution containing a rubbery substance is polymerized, the rubbery substance is made into particles, bulk polymerization is performed until a stable particle size is maintained, and suspension is suspended during the polymerization. Methods for transferring to polymerization are known, such as adding polystyrene before the start of polymerization (Japanese Patent Publication No. 41-19352, U.S. Patent No. 3,488,743, etc.), adding polystyrene during polymerization, and then continuing polymerization. (Japanese Patent Publication No. 43-13983, Japanese Patent Publication No. 43-21746, etc.), in which a part of the rubber-like material is polymerized, and then the rubber-like material and, if necessary, a styrene-based polymer are There is a method (Japanese Patent Publication No. 49-35074) in which a rubber-like substance is made into particles by adding coalescence. However, both of these techniques involve a suspension polymerization step. It is also known to add polystyrene before starting polymerization using either bulk-suspension polymerization or bulk polymerization (U.S. Patent No.
3144420, etc.). In bulk polymerization, a styrene solution of a rubber-like substance is polymerized, the rubber-like substance is made into particles, and the polymerization proceeds (as in U.S. Pat. No. 2,694,692, etc.), and after particle formation, a separately prepared polystyrene solution is polymerized. (U.S. Pat. No. 3,676,527).
is proposed. However, it is difficult to obtain a rubber-reinforced aromatic monovinyl resin that gives an excellent appearance (gloss, colorability) to a molded product, and it is even more difficult to obtain it by a continuous bulk polymerization method. has not been obtained. The present inventors have conducted intensive studies to produce a rubber-reinforced aromatic monovinyl resin that can provide molded products with excellent appearance through continuous bulk polymerization, which has various advantages, and have developed the novel production method of the present invention. I came to find out. [Means for Solving the Problems] That is, the present invention provides a solution in which a rubbery polymer is dissolved in an aromatic monovinyl monomer, etc., so that the ratio of the rubbery polymer to the produced polymer is within a certain range. The polymerization solution obtained by polymerizing up to The present invention relates to a continuous production method for a rubber-reinforced aromatic monovinyl resin, which is characterized in that after mixing, a constant shearing rate is applied to advance the heavy ginseng. More specifically, 3 to 15% by weight of a rubbery polymer, 55 to 15% by weight of an aromatic monovinyl monomer or a mixture of an aromatic monovinyl monomer and a monomer copolymerizable therewith.
A solution consisting of 97% by weight and 0 to 30% by weight of solvent, the ratio of the aromatic monovinyl polymer or copolymer to be produced and the rubbery polymer is in the range of 0.3 to 2.5,
A polymerization solution obtained by polymerization preferably in the range of 0.5 to 1.5 and a mixture of an aromatic monovinyl monomer or an aromatic monovinyl monomer and a monomer copolymerizable with it 70 to 100 % by weight, and a solution consisting of 0 to 30% by weight of a solvent to a polymerization rate of 45 ^% or more, preferably 50 ^% or more. The rubbery polymer is dispersed into particles by continuous mixing while applying speed, and then
Polymerization is carried out while applying a shear rate exceeding 20 sec ^-1 until the polymerization rate exceeds 50%, and if necessary, after proceeding with polymerization with or without applying shear force, unreacted monomers and solvent are removed. The present invention relates to a continuous production method for a rubber-reinforced aromatic monovinyl resin that provides a good appearance of a molded product, characterized in that a polymer is obtained by recovery. In the above method, in particular, the ratio of the aromatic monovinyl polymer or copolymer to the rubbery polymer in the polymerization solution () containing the rubbery polymer is from 0.3 to
2.5, preferably in the range of 0.5 to 1.5, and the polymerization rate of the polymerization solution () is 45%, preferably 50%
exceeds 130sec ^-1 in the mixer.
A combination of the above three requirements, preferably a high shear rate of 200 sec ^-1 or more, is effective, and by taking this combination, it is possible to obtain a resin with excellent appearance of molded products, especially gloss and colorability. This is possible. If the ratio of the aromatic monovinyl polymer or copolymer and the rubbery polymer in the polymerization solution () becomes too large, the coloring properties will be significantly poor, and if it becomes too small, the dispersion state of the rubber particles will be controlled. This results in poor gloss. Furthermore, if the polymerization rate of the polymerization solution (2) is too low, it will be impossible to control the dispersion state of rubber particles by applying a high shear rate with the mixer, resulting in poor gloss and colorability.
Furthermore, it is essential to provide a high shear rate in the mixer, and when the shear rate is high, both gloss and colorability will be excellent. After mixing in a mixer, it is necessary to further polymerize by applying a shear rate of 200 sec ^-1 or more until the polymerization rate exceeds 50%. If the shear rate is too low, a product with good gloss cannot be obtained. The rubber-like polymer in the present invention has 4 to 4 carbon atoms.
Conjugated 1,3-dienes of 6, such as homopolymers of 1,3-butadiene, copolymers of 1,3-butadiene and isoprene, 1,3-butadiene or 1,
Copolymers of 3-butadiene and isoprene with other copolymerizable compounds such as styrene, methylstyrene of nuclear alkyl-substituted styrenes, dimethylstyrene, acrylonitrile, methacrylonitrile, alkyl esters of acrylic acid and methacrylic acid. These may be used alone or as a mixture of two or more. Particularly preferred are polybutadiene rubber and butadiene-styrene copolymer rubber. The aromatic monovinyl monomer in the present invention is
Styrene and nuclear alkyl-substituted styrenes such as o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p -α-alkyl substituted styrene such as methylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene,
These are nuclear halogenated styrenes such as p-bromostyrene, 2-methyl-1,4-chlorostyrene, and 2,4-dibromostyrene, and vinylnaphthalene, which can be used alone or as a mixture of two or more of them. Monomers that can be copolymerized with aromatic monovinyl monomers include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, methacrylic esters such as methyl methacrylate, acrylic esters, methacrylic acid, acrylic acid, maleic anhydride, These include maleimides such as phenylmaleimide, and are used alone or as a mixture. Solvents used in the present invention include aromatic hydrocarbons, such as toluene, xylene, and ethylbenzene, singly or in mixtures of two or more. Furthermore, other solvents, such as resinous hydrocarbons and dialkyl ketones, may be used in combination with the aromatic hydrocarbons to the extent that they do not impair the dissolution of the rubbery substance and the polymerization product from the aromatic monovinyl monomer. can. The rubbery material is dissolved in the mixture with aromatic monovinyl monomer or solvent at a concentration of 3 to 15% by weight. The solvent is used in a range of 0 to 30% by weight. If it exceeds 30% by weight, the polymerization rate will decrease significantly and the impact strength of the resulting resin will decrease significantly. In addition, the energy required to recover the solvent is large, resulting in poor economic efficiency. The solvent may be added after the polymerization conversion reaches a relatively high viscosity, or may be added before the polymerization. It is preferable to add 5 to 15% by weight before polymerization in terms of quality uniformity and polymerization temperature control. Polymerize a simple substance to make a polymer solution (), a polymer solution ()
100 to 180℃ in the absence of a polymerization initiator
Polymerization may be carried out in the temperature range of 50 to
Polymerization can be carried out at a temperature range of 180°C, preferably 90-140°C. In order to obtain a resin with excellent colorability and impact strength, it is preferable to polymerize the rubber-like substance in the presence of an organic peroxide. The organic peroxide used in the present invention is 2,2-
Bis(t-butylperoxy)butane, 2,2-
Bis(t-butylperoxy)octane, 1,1
-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-
Peroxyketals such as 4,4-bis(t-butylperoxy)valate, di-t-butyl peroxide, t-butylcumyl peroxide,
Dicumyl peroxide, α,α′-bis(t-
butylperoxyisopropyl)benzene, 2,
Dialkyl peroxides such as 5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, acetyl peroxide, Isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-toluoyl peroxide Diacyl peroxides such as di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-myristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, etc. Peroxydicarbonates such as oxydicarbonate, di-methoxyisopropyl peroxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, t-butylperoxyacetate, t-butylperoxyisobutyl rate, t-butyl peroxy pivalate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy 3,5,5 -Trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butyldiperoxyisophthalate, 2,5-dimethyl-
2,5-di(benzoylperoxy)hexane,
Peroxy esters such as t-butylperoxyisopropyl carbonate, acetylacetone peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,
Ketone peroxides such as 5-trimethylcyclohexanone peroxide and methylcyclohexanone peroxide, t-butyl hydroperoxide, cumene hydroperoxide,
Di-isopropylbenzene hydroperoxide, p-mentha hydroperoxide, 2,5
- Hydroperoxides such as dimethylhexane 2,5-dihydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, polyacyl peroxides of dibasic acids,
There are polyperoxy esters of dibasic acids and polyols. In addition, during polymerization, chain transfer agents such as mercaptans, α-methylstyrene linear dimer, terpinolene, and antioxidants such as hindered phenols, hindered bisphenols, and hindered trisulfenols, such as 2, 6-di-t-butyl-4-methylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate may be used. The mixer used in the present invention needs to be able to instantly mix the polymerization solution () and the polymerization solution () at a high shear rate. In order to obtain resin with good appearance of molded products such as colorability and gloss,
130 sec ^-1 or more, preferably 200 sec ^-1 or more is required. The mixer may be of any type as long as it can provide a high shear rate as mentioned above, but for example, it can rotate at high speed and has stirring blades such as a turbine type, propeller type, rod type, paddle type, or ribbon type. A stirred mixer is used, but it is important that its design allows for high shear rates. After mixing the polymerization solution () and polymerization solution () in a mixer at a high shear rate, they are continuously taken out and fed to the next polymerization reactor to further proceed with polymerization, but at this time the polymerization rate It is necessary to apply a shear rate of 30 sec ^-1 or higher until the ratio exceeds 50%. At this time, if the shear rate is too low, the resulting rubber particle size distribution will be wide, which is unfavorable especially in terms of gloss. Therefore, it is important to apply shear force at this point in order to obtain a resin of good quality. If necessary, after polymerization is proceeded with or without shearing force, unreacted monomers and solvent are removed under vacuum at a temperature range of 180 to 260°C, for example, to obtain a resin. The rubber-reinforced aromatic monovinyl resin thus obtained contains 3 to 20% by weight of a rubbery polymer,
The size of the dispersed rubber particles is 0.7 to 3 microns, particularly preferably 0.8 to 1.5 microns, and the resin has excellent appearance of molded products such as colorability and gloss, and has an excellent balance between impact resistance and rigidity. The resin obtained in the present invention can be used by adding additives such as antioxidants, dyes and pigments, lubricants, fillers, mold release agents, plasticizers, and antistatic agents as necessary. [Effects of the Invention] According to the method of the present invention, it is possible to produce a rubber-reinforced aromatic monovinyl resin that has excellent appearance such as colorability and gloss, and has an excellent balance of impact resistance and rigidity through continuous bulk polymerization. . In general, impact resistance and coloring properties, impact resistance and gloss, and impact resistance and rigidity are contradictory properties, and the value of being able to obtain resins that are excellent in both of these properties using a highly economical continuous polymerization method. is large. It should be noted that good coloring properties are of great industrial significance because the cost of dyes and pigments used for coloring can be significantly reduced. The resin obtained by the method of the present invention can be used as molded products in the fields of light electrical equipment, miscellaneous goods, etc., and particularly favorable results can be obtained in molded products that require bright color tone and gloss. [Example] Examples are shown below. The data shown in the examples were measured based on the following method. Izot impact strength: According to ASTM D256.
Tensile strength: ASTM D638, Flexural modulus: ASTM
D790, gloss: ASTM D638 dumbbell test piece gate and end gate gloss (incidence angle 60°)
were measured and averaged. Particle size of rubbery substance in resin: Using a mixed electrolyte of dimethylformamide and ammonium thiocyanate with a Coulter counter (Coulter counter TA-type),
Put 4 grains in about 5 ml of dimethylformamide and add about 2
Let stand for ~5 minutes. Next, the dimethylformamide dissolved content is measured in a 30 micron aperture tube with an appropriate particle concentration. The 50% median diameter is taken as the average particle diameter. Shear speed: From the rotational speed Smm/sec of the protrusion of the rotating rotor or the tip of the stirring blade and the clearance rmm between the protrusion or the tip of the stirring blade and the machine wall,
It is calculated as (shear rate=S÷r). Example 1 Method for producing polymerization solution () 10% by weight of polybutadiene rubber was dissolved in 80% by weight of styrene monomer and 10% by weight of ethylbenzene, and 100 parts by weight of the solution and 0.08 parts by weight of 1,1-bis(t-butylperoxy)cyclohexane were added. , 0.10 parts by weight of 2,6-di-t-butyl-4-methylphenol, and 0.08 parts by weight of α-methylstyrene linear dimer were continuously fed into the first polymerization machine at a feed rate of 2/hour. and at a polymerization temperature of 95°C,
Polymerization was carried out until the ratio of polystyrene to rubber was 0.8 to obtain a polymerization solution (). Manufacturing method of polymerization solution () Styrene monomer 90% by weight and ethylbenzene 10%
and 0.08 parts by weight of a solution consisting of 1,1-bis(t-butylperoxy)cyclohexane
The solution consisting of parts by weight is continuously transferred to the second polymerization machine at a feed rate of 1/hour, and polymerization is carried out at a polymerization temperature of 95 to 110°C until the polymerization rate reaches 60% to obtain a polymerization solution (). Obtained. The polymerization solution () and polymerization solution () obtained above were continuously taken out from the first polymerization machine or the second polymerization machine and continuously supplied to a mixer having a rotating rotor with protrusions for 1700 sec ^{- 1} (rotor rotation speed 1080 rpm), mix the polymerization solution () and polymerization solution (), send the mixed solution to the third polymerization machine, and increase the polymerization rate to 58% while applying a shear rate of 30 sec ^-1 . Polymerized. After that, the solution sent to the fourth polymerization machine was further polymerized to a polymerization rate of 90%, and the solution was fed to the extruder with two vents.
Volatile components were removed under vacuum at 230°C, and the molten strand was drawn out from the die, cooled with water, and cut with a cutter to obtain resin pellets. Various physical properties of the obtained resin were measured and the results are shown in Table 1. Examples 2 to 4 In Example 1, when the mixer was a mixer with ribbon-type stirring blades and gave a shear rate of 770 sec ^-1 (Example 2), a mixer with multi-stage turbine-type stirring blades was used. Shear rate 235sec ^-1 (Example 3),
A resin was obtained in the same manner when 140 sec ^-1 (Example 4) was given. The results are shown in Table 1. Comparative Example 1 100% by weight solution of 6.7% by weight polybutadiene rubber dissolved in 83.3% by weight styrene monomer and 10% by weight ethylbenzene, 0.08 parts by weight of 1,1-bis(t-butylperoxy)cyclohexane, 2,6% by weight
-Di-t-butyl-4-methylphenol 0.07 parts by weight, α-methylstyrene linear dimer
Continuously supplying a solution consisting of 0.055 parts by weight to a polymerization machine having multistage turbine-type stirring blades,
Polymerization was carried out to a polymerization rate of 58% by applying a shear rate of 20 sec ^-1 . Subsequently, the solution sent to another polymerization machine was polymerized to a polymerization rate of 90%, and after removing volatile components in the same manner as in Example 1, pellet-shaped resin was obtained. The results are shown in Table 1. A method for manufacturing rubber-reinforced polystyrene by such a method is a commonly known method. The resin obtained by this method is inferior in colorability and gloss compared to the resin obtained by the method of the present invention,
The rigidity indicated by the flexural modulus is also poor. Comparative Examples 2 and 3 In Example 1, when the mixer was a mixer with a ribbon-type stirring blade and a shear rate of 100 sec ^-1 was applied (Comparative Example 2), a mixer with a multi-stage turbine-type stirring blade was used. A resin was obtained in the same manner when a shear rate of 60 sec ^-1 was applied (Comparative Example 3). The results are shown in Table 1. In this way, when a low shear rate is applied in the mixer, the rubber particle size cannot be reduced and the gloss is poor. Furthermore, the colorability is also inferior to that obtained in the examples of the present invention. Examples 5 to 6, Comparative Examples 4 and 5 In Example 3, the polymerization rate of the polymerization solution () was set to 45
%, and the ratios of polystyrene and rubber in the polymerization solution () were 0 (Comparative Example 4), 0.5 (Example 5), and 1.2, respectively.
(Example 6) and 3.0 (Comparative Example 5) (the polymerization rate was controlled by the polymerization temperature), resins were obtained in the same manner. The results are shown in Table 1. If the ratio of polystyrene to rubber in the polymerization solution () becomes too large, the colorability and gloss will decrease, and the rigidity will also decrease. Furthermore, if the ratio of polystyrene to rubber becomes too small, the rubber particle size will not become smaller even if a high shear rate is applied, resulting in a significant decrease in gloss. Comparative Examples 6 and 7 Resins were obtained in the same manner as in Example 2 except that the ratios of polystyrene and rubber in the polymerization solution () were changed to 0 (Comparative Example 6) and 0.2 (Comparative Example 7), respectively. The results are shown in Table 1. When the ratio of polystyrene to rubber is small in this way, the rubber particle size does not become small even when a high shear rate is applied, resulting in very poor gloss. Comparative Example 8 In Example 2, the polymerization rate of the polymerization solution () was set to 35
%, resins were similarly obtained. The results are shown in Table 1. If the polymerization rate of the polymerization solution () is low, even if a high shear rate is applied, the rubber particle size will not become small, resulting in very poor gloss. Comparative Example 9 A resin was obtained in the same manner as in Example 5 when the shear rate of the third polymerizer after exiting the mixer was set to 5 sec ^-1 . The results are shown in Table 1. If the shear rate of the third polymerizer is too low, both the gloss and the colorability will be inferior to the resin of the present invention.

【table】

【table】

Claims (1)

[Claims] 1 From 3 to 15% by weight of a rubbery polymer, 55 to 97% by weight of an aromatic monovinyl monomer or a mixture of an aromatic monovinyl monomer and a monomer copolymerizable therewith, and 0 to 30% by weight of a solvent. A polymer solution () obtained by polymerizing a solution such that the ratio of the aromatic monovinyl polymer or copolymer to the rubbery polymer to be produced is in the range of 0.3 to 2.5, and the aromatic monovinyl monomer or 70 to 100% by weight of a mixture of an aromatic monovinyl monomer and a monomer copolymerizable therewith;
and a solution consisting of 0 to 30% by weight of solvent at a polymerization rate of 45%.
Polymerization solution () obtained by polymerization above 130sec ^-1
The rubbery polymer is dispersed into particles by continuous mixing while applying a shear rate of
Polymerization is carried out while applying a shear rate exceeding 20 sec ^-1 until the polymerization rate exceeds 50%, and if necessary, after proceeding with polymerization with or without applying shear force, unreacted monomers and solvent are removed. A method for continuously producing a rubber-reinforced aromatic monovinyl resin that gives a good appearance to a molded product, the method comprising recovering a polymer.