JPH0372510A - Production of impact-resistant aromatic vinyl resin - Google Patents

Abstract

PURPOSE:To produce an arom. vinyl resin excellent in the impact resistance and gloss by radical-polymerizing an arom. vinyl compd. in the presence of a specific styrene-butadiene block copolymer in a specific manner. CONSTITUTION:A process of producing an impact-resistant arom. vinyl resin by radical-polymerizing an arom. vinyl compd. in the presence of a styrene- butadiene block copolymer, wherein copolymer is a block copolymer having a peak mol.wt. of lower than 200000 in the mol.wt. distribution by gel permeation chromatography, a total styrene content of 15-35wt.%, a vinyl group content in the butadiene part of 35wt.% or lower, and a block styrene content per total styrene content of 50-95wt.%. In the process, the median of the diameter of coarse particles dispersed in the resin is adjusted to 0.3-1.0mum, thus obtaining a purpose resin.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Application Field The present invention relates to a method for producing an impact-resistant aromatic vinyl resin, and more particularly, to a method for producing an impact-resistant aromatic vinyl resin, and more specifically, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more particularly, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more particularly, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more particularly, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more particularly, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more specifically, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more specifically, it relates to a method for producing an impact-resistant aromatic vinyl resin, and more specifically, it relates to an impact-resistant aromatic vinyl resin that has excellent impact resistance and excellent appearance characteristics such as gloss. The present invention relates to a method for producing an aromatic vinyl resin.

b. Conventional technology Conventionally, in order to improve the impact resistance of aromatic vinyl resin,
Methods of bulk polymerization or bulk-suspension polymerization of aromatic vinyl compounds in the presence of unvulcanized rubber are known, but depending on such polymerization methods, it is not always possible to obtain good results in terms of appearance characteristics. Can not.

On the other hand, in order to improve the appearance characteristics of aromatic vinylene resins, a method using a styrene-butadiene block copolymer is known (Japanese Patent Publication No. 41-14234, Japanese Patent Publication No. 41-14234,
No. 2-17492, Japanese Patent Publication No. 44-7126, Japanese Patent Publication No. 1983
1-143415). However, although either method improves the appearance characteristics of the resin to some extent, it often results in a significant decrease in impact resistance, making it impossible to achieve both impact resistance and appearance characteristics.

Problems to be Solved by the C6 Invention In view of the above circumstances, the inventors of the present invention conducted intensive studies to obtain an impact-resistant aromatic vinyl resin that has a highly balanced impact resistance and appearance characteristics. By radically polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene block copolymer having a specific structure and adjusting the diameter of dispersed rubber particles in the resulting resin to a specific range,
The inventors have discovered that the above technical problems can be solved, and have arrived at the present invention.

60 Means for Solving the Problems The present invention provides a manufacturing method of radically polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene block copolymer, in which the styrene-butadiene block copolymer is: The peak molecular weight of the molecular weight distribution of the polymer is less than 200,000; ■ The total styrene content is 15 to 35% by weight; ■ The amount of vinyl bond in the butadiene portion is 35% by weight or less; ■ The blocked styrene content is less than the total styrene content. 50-9
5%, and the median particle size of the rubber particles dispersed in the resulting resin is adjusted to fall within the range of 0.3 to 1.0 μm. The present invention provides a method for producing a resin based resin.

The present invention will be explained in detail below.

The above styrene-butadiene block copolymer can be obtained in a hydrocarbon solvent using an organolithium catalyst by the method shown below, but the manufacturing method is not limited thereto. That is, as long as the styrene-butadiene block copolymer having the above specific structure can be obtained, it can be obtained by any method, including not only polymerization but also a mixture of two or more different block copolymers. It can also be used.

Furthermore, a styrene-butadiene block copolymer containing an isoprene unit in the butadiene portion of 30% by weight or less can also be used.

One of the preferred methods for producing the styrene-butadiene block copolymer is a method in which butadiene/styrene and styrene are sequentially block copolymerized in a hydrocarbon solvent using an organolithium compound as an initiator.

The hydrocarbon solvent is not particularly limited, but aliphatic, alicyclic, and aromatic hydrocarbon compounds that are wavy under polymerization conditions can be used. Preferred hydrocarbon solvents include pentane, n-hexane, n-hebutane, isooctane, n-decane, cyclohexane, methylcyclopentane, benzene, diethylbenzene, etc., and not only one type but two or more of these can be used. It may be a mixture of.

The organic lithium compound is one in which at least one lithium atom is bonded to a hydrocarbon, such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, 5ec-butyllithium, t-
Butyllithium, n-hexyllithium, cyclohexyllithium, lithium benzene, lithium naphthalene,
1,4-dilithiobutane, 1,5-dilithiopentane,
1.10-dilithiodecane, 1.3.5-4 lylithiocyclohexane, etc., and preferred examples include monolithium hydrocarbon compounds such as n-butyllithium, 5eC-butyllithium, and t-butyllithium.

In the above method for producing a copolymer, an ether or a tertiary amine compound can be added as long as the amount of vinyl bond in the butadiene moiety in the copolymer to be produced does not exceed 35% by weight. Specific examples of ethers and tertiary amines that can be added include ethyl ether, tetrahydrofuran, dioxane, ethylene glycol methyl ether, diethylene glycol dimethyl ether, triethylamine, pyridine, NNN'N'-tetramethylethylenediamine, and the like.

In the present invention, the styrene-butadiene block copolymer used has a specific structure.

As the styrene-butadiene block copolymer of the present invention, AB type and ABA type block copolymers are used, and AB type block copolymers are preferably used.

The peak molecular weight of the molecular weight distribution of the above styrene-butadiene block copolymer by GPC is less than 200,000, preferably 50,000 to 180,000, more preferably 80,000 to 150,000. If it exceeds 200,000, the viscosity of the 5% styrene solution becomes too high, and the desired particle size may not be obtained, which is not preferable.

The total styrene content of the styrene-butadiene block copolymer is 15-35% by weight. If it is less than 15% by weight, the resulting resin will have poor gloss.

If it exceeds 35% by weight, the resulting resin will have poor impact resistance.

The amount of vinyl bond in the butadiene moiety of the styrene-butadiene block copolymer is 35% or less, preferably 14%.
~25%. If it exceeds 35%, the gloss is good, but the impact resistance, especially at low temperatures, is poor.

The block ratio of the block styrene content to the total styrene content of the above styrene-butadiene block copolymer is 5
It is 0-95%. If the block rate is less than 50%, the dispersed rubber particles may become irregular and the resulting resin may have poor gloss, which is undesirable. If the block rate exceeds 95%, the impact resistance may decrease, which is not preferable.

In addition, 2 of the above styrene-butadiene block copolymer
The viscosity of the 5% by weight styrene solution at 5°C is preferably 30 centipoise or less.

More preferably, it is 3 to 15 centipoise, particularly preferably 5 to 12 centipoise. If it exceeds 30 centipoise, the viscosity of the rubber during HIPS polymerization becomes too high, leading to poor phase rotation of dispersed rubber particles, uneven particle diameters, and the resulting resin tends to have poor gloss.

In the production method of the present invention, the styrene-butadiene block copolymer having the above-mentioned specific structure is used, and at the same time, the median particle diameter of the rubber particles (block copolymer particles) dispersed in the resulting resin is set to 0.3. It is necessary to adjust the thickness to a range of ~1.0 μm, preferably a range of 0.4 to 0.9 μm.

If the median particle size is less than 0.3 μm, the Izot impact strength will be poor, and if it exceeds 1.0 μm, only a product with poor surface gloss will be obtained.

The particle size of the rubber particles can be adjusted by changing the shape of the stirring device in the polymerization tank,
It depends on various factors such as the rotation speed of the stirrer, the stirring time, the polymerization temperature, etc., and cannot be determined unambiguously, but in general, conditions that apply stress to the rubber during stirring during graft polymerization, such as This can be done by increasing the rotational speed and decreasing the particle size.

The production method of the present invention uses the above-mentioned specific styrene-butadiene block copolymer and graft-polymerizes an aromatic vinyl compound thereto.

Examples of the above aromatic vinyl compounds include styrene, α-
Examples include methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinylethylbenzene, and vinylxylene, but styrene, α-methylstyrene, and p-methylstyrene are preferred.
More preferred is styrene.

The mixing ratio of the styrene-butadiene block copolymer and the aromatic vinyl compound is 6 to 25% by weight, preferably 8 to 20% by weight, more preferably 10 to 13% by weight, and 94 to 75% by weight of the latter. , preferably 92-85
% by weight, more preferably 90-87% by weight. If the amount of the styrene-butadiene block copolymer used is less than 6% by weight, the impact resistance of the resulting resin will decrease, making it difficult to achieve the object of the present invention, and if it exceeds 25% by weight, the viscosity of the graft polymerization solution will become extremely low. This makes it difficult to actually carry out graft polymerization.

The method of radical polymerizing the aromatic vinyl compound to the specific styrene-butadiene block copolymer is not particularly limited. For example, it can be carried out by bulk polymerization of an aromatic vinyl compound solution in which the styrene-butadiene block copolymer is dissolved, or by radical polymerization by combining bulk polymerization and suspension polymerization.

When radically polymerizing a styrene-butadiene block copolymer and an aromatic vinyl compound by bulk polymerization,
The styrene-butadiene block copolymer is dissolved in an aromatic vinyl compound, and then, if necessary, a molecular weight regulator is added.

Examples of the molecular weight regulator include α-methylstyrene dimer, n-decylmercaptan, tert-dodecylmercaptan, 1-phenylbutene-2-fluorene, and mercaptans such as dipentene and chloroform;
Terpenes, halogen compounds, etc. are used.

In addition, in order to improve the moldability of the resulting resin,
- A lubricant is added for boat fishing. Examples include ester lubricants such as butyl stearate and butyl phthalate, and lubricants used in conventional resin processing such as mineral oil and paraffin wax.

After dissolving these molecular weight regulators and lubricants in the polymer solution, for example, benzoyl peroxide,
lauroyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, dicumyl peroxide, diisopropyl peroxydicarbonate, tert-butyl peroxyacetate, di-t
Add ert-butylperoxyisophthalate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, or azobisisobutyronitrile, and lower the reaction temperature under an inert gas atmosphere. The reaction is completed at 60-200° C. with stirring. Moreover, when carrying out thermal polymerization without a catalyst, the heating polymerization is usually carried out at 100 to 200°C to complete the reaction.

During the bulk polymerization reaction, it is generally preferable to stir effectively until the polymerization rate of the aromatic vinyl compound reaches about 30%. It is necessary to adjust the stirring so that it is within the range of the present invention. On the other hand, after the weight percentage of the aromatic vinyl compound exceeds about 30%,
Preferably, the stirring is moderate.

Further, at this time, a hydrocarbon solvent such as toluene, ethylbenzene, xylene, etc. may be added in order to reduce the viscosity of the polymerization system.

After the polymerization is completed, the monomer and solvent are recovered by removing the monomer and the solvent using a vent-type router or steam stripping.

When radical polymerization is carried out by a combination of bulk polymerization and suspension polymerization, the bulk polymerization is first carried out until about 10 to 45% by weight of the monomer (aromatic vinyl compound) is converted into a polymer, and then the reaction solution is mixed with polyvinyl alcohol. ,
It is dispersed in an aqueous solution containing a suspension stabilizer such as polymethacrylate or tricalcium phosphate, and the reaction temperature is raised to 60 to 160° C. while maintaining the suspension state to complete polymerization.

After the polymerization is completed, the suspension stabilizer is removed by washing with water and dried, and then the aromatic vinyl resin is recovered.

In addition, when performing radical polymerization by the bulk polymerization or bulk-suspension polymerization, it is preferable that 50% by weight or more of the monomer used is the aromatic vinyl compound, and less than 50% by weight of the monomer is acrylonitrile other than the above compound. , methacrylonitrile, acrylic acid, methyl acrylate, methyl methacrylate, and other aliphatic vinyl compounds.

In addition, known antioxidants, such as 2,6-tert-butyl-4-methylphenol, 2-(1-methylcyclohexyl)-4
, 6-dimethylphenol, 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol)
, 4,4'-thiobis-(6-tert-butyl-3
-methylphenol), dilaurylthiodipropionate, tris(di-nonylphenyl)phosphite, waxes; known UV absorbers such as p-tert-butylphenyl salicylate,2. 2'-dihydroxy-4-methoxybenzophenohene, 2-(2'-hydroxy-4'-n-octoxyphenyl)benzothiazole; known lubricants such as paraffin wax, stearic acid, hydrogenated oils, stearamide, methylene bis stearamide, n-butyl stearate, ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride; known flame retardants such as antimony oxide, aluminum hydroxide, zinc borate, tricresyl phosphate, chlorinated paraffin, tetra Bromobutane, hexabromobenzene, tetrabromobisphenol A; known antistatic agents, such as stearamidopropyl dimethyl-β-hydroxyethylammonium nitrate; known colorants, such as titanium oxide, carbon black, other inorganic or organic Pigments; known fillers such as calcium carbonate, clay, silica, glass fibers, glass spheres, carbon fibers, etc. can be added as necessary.

e. Examples Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the examples, unless otherwise specified, parts and % indicate parts by weight and % by weight.

Moreover, the data shown in the examples were measured according to the following method.

The microstructure of the butadiene moiety of the styrene-butadiene block copolymer was measured by an infrared method (Morello method), and the styrene solution viscosity was measured by a Cannon-Fenske viscometer.

The amount of bound styrene in the styrene-butadiene block copolymer was determined by measuring the intensity of the infrared absorption peak due to phenyl groups at a wave number of 699 cm'', and determining the amount from a previously determined calibration curve.

Further, the molecular weight distribution of the styrene-butadiene block copolymer was measured using HLC-802A type GPC manufactured by Toyo Soda Kogyo ■ under the following conditions.

Column: 2 columns GMHXL manufactured by Toyo Soda Kogyo ■ Mobile phase: Tetrahydrofuran sample concentration 20.1% by weight Measurement temperature: 40°C Detector: Differential refractometer MW/Mn and PM are M converted to standard polystyrene.
w, Mn, and PM were determined and calculated. Styrene
The amount of block styrene in the butadiene block copolymer is
+H-NMR Rubb, Chem, Tech,
, 54.685 (1981).

Furthermore, the molecular weight of the block styrene portion of the styrene-butadiene block copolymer was measured by an ozonolysis-GPC method.

The physical properties of the impact-resistant polystyrene resin were measured according to the following method.

Izotsu impact strength (1/4 inch, with notch): 8
Regarding the molded product obtained by molding using an oz injection molding machine at a cylinder temperature of 200°C, AsTM D-256
Measured according to.

Tensile strength: Using 802 injection molding machine, cylinder temperature 2
For molded products obtained by molding at 00°C, ASTM
Measured according to D-638.

Gloss: Using an 8oz injection molding machine, cylinder temperature 200
For molded products obtained by molding at °C, ASTM D
-523, the reflective gloss at 60°C was measured.

Measurement of median particle size of dispersed rubber particles: Resin pellet 1
~2 tablets are placed in about 50 dimethyl formamide, and about 3
After standing for a while, this dimethylformamide solution was added to the electrolytic solution (ISOTON ■■), measured with a Coulter counter to obtain an appropriate particle concentration, and the 50% median diameter was calculated from the obtained particle size distribution. It was determined by

When the particle size was 0.4 μm or less, the dimethylformamide solution was measured using a Coulter N4 type submicron particle analyzer.

Example 1 18 kg of cyclohexane, 2.4 kg of butadiene, and 0.0 kg of styrene were placed in a reactor with a jacket and a stirrer having an internal volume of 501 kg.
After charging 0.7kg and 0.9g of tetrahydrofuran and adjusting the temperature to 45℃, 2.55g of n-butyllithium was added.
was added and polymerized. Ten minutes after reaching the maximum temperature, 0.33 kg of styrene was added, and polymerization was continued for an additional 30 minutes. Add 2.6- to this polymer solution as a stabilizer.
After adding tert-butyl-4-methylphenol at a ratio of 0.5% to the polymer, the solvent was removed by steam stripping, and the block polymer was obtained by drying with a hot roll at 100 °C. Ta.

Table 1 shows the properties of the obtained polymer.

Table 2 shows 12 parts of this block polymer and 88 parts of styrene.
A mixture having the composition was stirred at room temperature for 8 hours to uniformly dissolve the mixture. This solution was transferred to a reactor with an internal volume of 10fi and equipped with a jacket and stirrer, and 0.05% of tert-dodecyl mercaptan was
of styrene was added and polymerized at 105° C. until the polymerization rate of styrene reached about 30%. Note that the stirring at this time was 45 Orr.
The rotation speed was pm. Next, this polymerization solution 100
Add 0.05 parts per part of dicumyl peroxide, further add 150 parts of water containing 3 parts of tribasic calcium phosphate as a suspension stabilizer and 0.005 parts of sodium dodecylbenzenesulfonate as a surfactant, and stir. The solution was suspended below. This suspension mixture was polymerized by heating at 120° C. for 4 hours and at 140° C. for 4 hours while stirring. The obtained bead-shaped resin was separated from each other, washed with water, dried with hot air, and then pelletized using an extruder. The impact-resistant styrene resin thus obtained was injection molded to give test pieces for measuring physical properties. Table 2 shows the measurement results for each physical property.

Example 2 In Example 1, 2.1 kg of butadiene, 0.27 kg of styrene before polymerization, and 0.1 kg of tetrahydrofuran were added.
The same method as in Example 1 was carried out, except that 5g of n-butyllithium and 2.65g of n-butyllithium were used.The amount of styrene after the start of polymerization was changed to 0.63kg.

The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Example 3 In Example 1, 0.06 kg of styrene before polymerization,
0.15g of tetrahydrofuran, 2.65g of n-butyllithium, and 0.24k of styrene after starting polymerization.
It was carried out in the same manner as in Example 1 except for changing to g.

The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Comparative Example 1 In Example 1, except that styrene was not charged before polymerization and the amount of styrene was changed to 0.3 kg after starting polymerization,
It was carried out in the same manner as in Example 1. Table 1 shows polymer properties.
The physical property measurement results are shown in Table 2.

Comparative Example 2 In Example 1, the amount of tetrahydrofuran was changed to 1.6 g.
The same method as in Example 1 was carried out except that the method was changed to . The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Example 4 In Example 1, 1.8 kg of butadiene and 0.8 kg of styrene before polymerization were used. 54kg, n ~ butyl lithium 1
．． The procedure was the same as in Example 1, except that the amount of styrene after polymerization was changed to 0.66 kg. The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Comparative Example 3 The same method as in Example 1 was carried out except that n-butyllithium was changed to 1.2 g. The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Comparative Example 4 In Example 1, butadiene was added to 1.5 kg, styrene before polymerization was added to 0.3 kg, and n-butyllithium was added to 2.0 kg.
The same method as in Example 1 was carried out except that the amount of styrene after the start of polymerization was changed to 65 g and 1.2 kg. The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Comparative Example 5 In Example 1, 2.7 kg of butadiene and 0.0 kg of styrene before polymerization were used. 258kg1. The same method as in Example 1 was carried out except that the amount of styrene used after the start of polymerization was changed to 0.042 kg. The polymer properties are shown in Table 1, and the physical property measurement results are shown in Table 2.

Examples 1-4 maintain the balance of excellent impact resistance and gloss that was within the scope of the present invention.

On the other hand, in Comparative Example 1, the block rate of styrene was higher than the range of the present invention and the impact resistance was poor, and in Comparative Example 2, the vinyl content of the butadiene moiety in the copolymer was higher than the range of the present invention, so especially at low temperatures. impact resistance is poor. Furthermore, in Comparative Example 3, the peak molecular weight of the molecular weight distribution by GPC of the copolymer was higher than the range of the present invention, and as a result, the particle size could not be made finer and the gloss was inferior. In Comparative Example 4, the total styrene content was Since it is higher than the range of the invention, the impact resistance is inferior. Furthermore, Comparative Example 5 has poor gloss because the total styrene content is lower than the range of the present invention.

Margin below F9 Effects of the Invention According to the present invention, an aromatic vinyl resin with high gloss and excellent impact resistance can be obtained, and can be used as parts of household electrical appliances such as televisions, refrigerators, air conditioners, and washing machines, personal computers, word processors, etc. It is extremely useful for office equipment parts, building materials, miscellaneous goods, etc.

Claims (1)

[Scope of Claims] [1] A method for producing an impact-resistant aromatic vinyl resin by radically polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene block copolymer, wherein the styrene-butadiene block copolymer is As a polymer, (1) Gel permeation chromatography (GPC)
), the peak molecular weight of the molecular weight distribution of the copolymer is less than 200,000, (2) the total styrene content is 15 to 35% by weight, (3) the vinyl bond content of the butadiene moiety is 35% by weight or less, (4) the block Styrene content is 50~ of total styrene content
95%, and the median particle diameter of rubber particles dispersed in the resulting resin is adjusted to fall within the range of 0.3 to 1.0 μm. Method for producing resin.