JPH06102704B2 - Method for producing impact-resistant aromatic vinyl resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an impact-resistant aromatic vinyl-based resin, and more specifically, an aromatic aromatic vinyl-based resin in the presence of a specific butadiene (co) polymer. Impact-resistant aromatic vinyl type used as a molding material for various molded products, such as electrical products, furniture and building materials, which are required to have excellent impact resistance, good luster and excellent coloring by graft polymerization of vinyl compounds. It relates to a method for producing a resin.

[Prior Art] Impact-resistant aromatic vinyl resins are widely used as molding materials for molded articles requiring impact resistance because they have excellent impact resistance as well as moldability and other physical properties. However, in order to expand its applications and improve the quality of products obtained from the impact-resistant aromatic vinyl-based resin, excellent impact resistance,
It is desired to have good gloss and excellent colorability.

Generally, in order to improve the gloss of the impact-resistant aromatic vinyl-based resin, it is necessary to use a raw material rubber (polybutadiene) having a low solution viscosity and a polybutadiene portion having a high vinyl bond content.

However, when a raw material rubber having a low solution viscosity or a polybutadiene having a high vinyl bond content is used, there arises a problem that the impact resistance of the resulting impact resistant aromatic vinyl resin is lowered.

As described above, in the impact-resistant aromatic vinyl-based resin, gloss and colorability and impact resistance are contradictory characteristics, and impact-resistant aromatic vinyl having good gloss without lowering impact resistance. It was difficult to obtain a system resin.

In order to solve the above-mentioned problems, a method of using polybutadiene having a relatively high molecular weight obtained by a lithium-based catalyst as a raw material rubber has been proposed (JP-A-61-143414).

However, even with this method, the level of impact resistance is still insufficient.

[Problems to be Solved by the Invention]

The present invention has been made on the background of the above-mentioned problems of the prior art, wherein an aromatic vinyl compound is graft-polymerized in the presence of a butadiene-based (co) polymer having a specific microstructure and a specific solution viscosity, and By adjusting the dispersed rubber particles in the obtained resin to a specific particle diameter range and adjusting the intrinsic viscosity to a certain value or more, impact-resistant aromatic vinyl having a high balance of impact resistance and gloss and colorability. The purpose is to provide a resin.

[Means for Solving the Problems]

In the present invention, when the aromatic vinyl compound is graft-polymerized in the presence of a butadiene-based (co) polymer, the butadiene-based (co) polymer is (a) a 5 wt% styrene solution viscosity measured at 25 ° C. "Styrene solution viscosity" is 550 to 2,000 centipoise, and the total vinyl bond content is more than 20 mol% and 70 mol% or less (hereinafter referred to as "butadiene (co) polymer (a)"), Or (b) Styrene solution viscosity is 200 to 2,000 centipoise, total vinyl bond content is 20 mol% or less, and vinyl bond content is 15 mol% or less (hereinafter sometimes referred to as "low vinyl part"). Is a mixture or block type containing 30 to 95% by weight and 70 to 5% by weight of a portion having a vinyl bond content of 25 to 75 mol% (hereinafter sometimes referred to as "high vinyl portion") (hereinafter referred to as "butadiene type"). ( ) Polymer (b)), and in the graft polymerization, the molecular weight regulator is 300 ppm or less with respect to the aromatic vinyl compound, and the average particle diameter of the dispersed rubber particles dispersed in the obtained resin is in the range of 0.4 to 2.5 μm. Further, the present invention provides a method for producing an impact-resistant aromatic vinyl-based resin, characterized in that the intrinsic viscosity of the resin is adjusted to 0.7 to 1.4 dl / g.

Examples of the butadiene (co) polymer used in the present invention include polybutadiene rubber and butadiene-isoprene rubber.

In this butadiene-based (co) polymer, the content of other monomers such as isoprene copolymerized with 1,3-butadiene is 30% by weight or less, preferably 15% by weight or less.

The styrene solution viscosity of this butadiene-based (co) polymer is
In the case of butadiene (co) polymer (a), 550-2,000cp
s, preferably 600 to 1,500 cps, and in the case of the butadiene-based (co) polymer (b), 200 to 2,000 cps, preferably 600 to 1,500 cps, and when the styrene solution viscosity is too low. , It is difficult to achieve the particle size and the intrinsic viscosity of the rubber particles dispersed in the aromatic vinyl resin at the same time, and the impact resistance of the resulting resin is poor, while it is industrially difficult to obtain more than 2,000 cps. In addition, the particle size of the rubber particles becomes uneven and the gloss decreases.

The vinyl bond content of the butadiene (co) polymer is
In the case of the butadiene-based (co) polymer (a), the total vinyl bond content is more than 20 mol% and 70 mol% or less, and in the case of the butadiene-based (co) polymer (b), the total vinyl bond content is If the content is 20 mol% or less and the vinyl bond content is 15 mol% or less, 30 to 95% by weight, and the vinyl bond content is 25 to
It is necessary that the 75 mol% portion is a mixture or block type containing 70 to 5% by weight.

In the case of the butadiene-based (co) polymer (a), when the total vinyl bond content is 20% or less, the coloring property is poor, while when it exceeds 70 mol%, the coloring property is good but the impact resistance at low temperature is deteriorated. Not preferable.

The total vinyl bond content of the butadiene (co) polymer (a) is
It is preferably 25 to 60 mol%.

On the other hand, in the case of the butadiene-based (co) polymer (b), the total vinyl bond content is 20 mol% or less, preferably 1 to 17 mol%, more preferably 2 to 16 mol%. When it exceeds the above range, the gloss is good but the impact resistance at low temperature is lowered, which is not preferable. Also, this butadiene type (co)
The polymer (b) has a vinyl bond content of 15 to 30 mol%, preferably 30 to 95 wt%, preferably 50 to 90 wt%, more preferably 70 to 90 wt%, and a vinyl bond content of 25 to 75 mol%. %
Part is 70 to 5% by weight, preferably 50 to 10% by weight, and more preferably 30 to 10% by weight. If the latter part is less than 5% by weight, the coloring property is inferior. %, The impact resistance at low temperature decreases, which is not preferable.
Here, the term “comprising” may be a blend of two kinds of butadiene-based (co) polymers having different vinyl bond contents, or a block (co) comprising two or more kinds of blocks having different vinyl bond contents. It may be a polymer.

The butadiene (co) polymer of the present invention has a trans 1,4 bond content of 1 to 70 mol% and a cis 1,4 bond content of 22.
It is about 99 mol%.

In addition, the Mooney viscosity (ML) of butadiene-based (co) polymers
_{1 + 4} , 100 ° C., hereinafter abbreviated as “Moonie viscosity”) is preferably about 50 to 200, more preferably about 100 to 180.

In the present invention, the above-mentioned specific butadiene-based (co) polymer is used, and at the same time, dispersed rubber particles dispersed in the resulting resin [graft (co) polymer and butadiene-based (co) polymer particles ] Average particle size 0.4 ~ 2.5μ
m, preferably 0.5 to 2.0 μm.

If the average particle size is less than 0.4 μm, the Izod impact strength is poor, while if it exceeds 2.5 μm, only the surface gloss is poor.

Further, the intrinsic viscosity of the resin obtained by the present invention is 0.7
It is ~ 1.4 dl / g, and less than 0.7 dl / g is not preferable because the impact resistance is poor.

As described above, in order to adjust the average particle diameter to a specific range of 0.4 to 2.5 μm in a range of high intrinsic viscosity, it is usually necessary to adjust the rotation number of stirring during graft polymerization as is performed. Difficult, the amount of the molecular weight regulator is extremely small,
It is preferable to use a butadiene-based (co) polymer having a specific solution viscosity of 300 ppm or less with respect to the aromatic vinyl compound.

The butadiene-based (co) polymer used in the present invention is
Obtained by solution polymerization. In particular, in a hydrocarbon solvent,
It is preferable that solution (co) polymerization of 1,3-butadiene and, if necessary, the other monomer is carried out using a known lithium-based or nickel-based catalyst as an initiator.

The hydrocarbon solvent is not particularly limited, but aliphatic, alicyclic and aromatic hydrocarbons that are liquid under the polymerization conditions can be used.

Preferred hydrocarbon solvents include, for example, pentane, n-
Hexane, n-heptane, isooctane, n-decane,
Cyclohexane, methylcyclopentane, benzene, diethylbenzene and the like are mentioned, and these may be not only one kind but also a mixture of two or more kinds.

In the production method, ether or a tertiary amine compound can also be added as a microstructure modifier. Specific examples of this ether and tertiary amine include ethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylamine, pyridine, N, N, N ′, N′-tetramethylethylenediamine, and the like. The temperature is usually greenhouse-200 ° C, preferably 50-150 ° C.
Is. The polymerization reaction may be a batch system or a continuous system.

The monomer concentration in the hydrocarbon solvent is usually 5 to 50% by weight, preferably 10 to 30% by weight.

The present invention uses the specific butadiene-based (co) polymer and graft-polymerizes an aromatic vinyl compound on the butadiene-based (co) polymer.

Examples of the vinyl aromatic compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinylethylbenzene and vinylxylene, but preferably styrene,
α-Methylstyrene and p-methylstyrene, and more preferably styrene.

Regarding the mixing ratio of the butadiene (co) polymer and the aromatic vinyl compound, the former is 3 to 25% by weight, preferably 5 to 15% by weight, more preferably 7 to 13% by weight, and the latter is 97 to 75% by weight. , Preferably 95-85% by weight, more preferably 93-
87% by weight. If the amount of the butadiene-based (co) polymer used is less than 3% by weight, the impact resistance of the resulting resin will decrease,
It is difficult to achieve the object of the present invention. On the other hand, if it exceeds 25% by weight, the viscosity of the graft polymerization solution becomes very high, so that the graft polymerization actually becomes difficult and the mechanical strength such as tensile strength is lowered.

The method for graft-polymerizing the aromatic vinyl compound on the specific butadiene-based (co) polymer is not particularly limited, but for example, the aromatic vinyl compound solution in which the butadiene-based (co) polymer is dissolved is bulk polymerized. Or bulk polymerization-
It can be carried out by a method of radical polymerization in combination with suspension polymerization.

When radically polymerizing a butadiene (co) polymer and an aromatic vinyl compound by bulk polymerization, the butadiene (co) polymer is dissolved in the aromatic vinyl compound, and then a molecular weight modifier is added if necessary. To do.

Examples of the molecular weight regulator include mercaptans such as α-methylstyrene dimer, n-decyl mercaptan, t-dodecyl mercaptan, 1-phenylbutene-2-fluorene, dipentene and chloroform, terpenes,
A halogen compound or the like is used.

In addition, in order to improve the moldability of the obtained resin,
Common lubricants are added. As examples thereof, ester-based lubricants such as butyl stearate and butyl phthalate, and lubricants used in conventional resin processing such as mineral oil and paraffin wax can be used.

These molecular weight regulators and lubricants, after dissolving in the polymer solution, for example benzoyl peroxide, lauroyl peroxide, cumene hydride peroxide, methyl ethyl ketone peroxide, as an initiator,
Dicumyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxyacetate, di-t
-Butyldiperoxyisophthalate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, azobisisobutyronitrile, etc. were added and the reaction temperature was adjusted to 60 at an inert gas atmosphere. Complete the reaction with stirring at ~ 200 ° C.

In the case of thermal polymerization without a catalyst, it is usually 100 to 200 ° C.
In order to complete the reaction, heat polymerization is carried out.

During the bulk polymerization reaction, it is usually preferable to effectively stir the polymer of the aromatic vinyl compound until it reaches about 30%, and particularly in the present invention, the average particle diameter of the dispersed rubber particles is Agitation should be adjusted to be within the scope of the invention. On the other hand, after the polymerization rate of the aromatic vinyl compound exceeds about 30%, it is preferable to moderate the stirring.

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

After the completion of the polymerization, the monomer and the solvent are recovered by removing the monomer and removing the solvent by a vented ruder or steam stripping.

In the case of radical polymerization by a combination of bulk polymerization-suspension polymerization, first, bulk polymerization is 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 added. Polyvinyl alcohol, polymethacrylate, tribasic calcium phosphate and the like are dispersed in an aqueous solution in which a suspension stabilizer is dissolved, and the reaction temperature is maintained at 60 to 160 ° C. while maintaining the suspension state to complete the polymerization. After the polymerization is complete, the suspension stabilizer is thoroughly washed with water to remove it,
The aromatic vinyl resin is recovered.

In the radical polymerization by bulk polymerization or bulk one 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 compound. ,
Methacrylonitrile, acrylic acid, methyl acrylate,
It may be replaced with an aliphatic vinyl compound such as methyl methacrylate.

The resins obtained by the above-mentioned polymerization methods are known antioxidants such as 2,6-di-t-butyl-4-methylphenol and 2- (1-methylcyclohexyl) -4,6-dimethylphenol. , 2,2'-methylene-bis (4-ethyl-
6-t-butylphenol), 4,4'-thiobis- (6
-T-butyl) -3-methylphenol, dilaurylthiodipropionate, tris (di-nonylphenyl) phosphite, wax; UV absorbers such as pt-
Butylphenyl salicylate, 2,2'-dihydroxy-
4-methoxybenzophenone, 2- (2'-hydroxy-4'-n-octoxyphenyl) benzothiazole;
Lubricants such as paraffin wax, stearic acid, hydrogenated oil, stearamide, methylenebis stearamide, n
-Butyl stearate, ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride; flame retardants such as antimony oxide, aluminum hydroxide, zinc borate, tricresyl phosphate, chlorinated paraffin, tetrabromobutane, hexabromobenzene. , Tetrabromobisphenol A; antistatic agents such as stearoamidopropyldimethyl-β-hydroxyethylammonium nitrate; colorants such as titanium oxide, carbon black and other inorganic or organic pigments; fillers such as calcium carbonate, clay , Silica, glass fiber, glass sphere, carbon fiber and the like can be added as required.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, parts and% indicate parts by weight and% by weight, unless otherwise specified.

The data shown in the examples were measured according to the following methods.

The microstructure of the butadiene-based (co) polymer was measured by the infrared method (Morero method).

The viscosity of a 5 wt% styrene solution measured at 25 ° C. was measured with a Canon Fenske viscometer.

Mooney viscosity is L-type rotor at a temperature of 100 ℃,
After preheating for 1 minute with a Mooney machine, the value at the 4th minute was measured.

The average particle size of the dispersed rubber particles is such that 1 to 2 resin pellets are put in about 50 ml of dimethylformamide and left for about 3 hours, and then this dimethylformamide solution is used as an electrolytic solution (ISOTON II, Coulter Scientific Japan). (Manufactured by K.K.) and measured with a Coulter counter as an appropriate particle concentration, and 50% median diameter was calculated from the obtained particle size distribution.

When the average particle diameter was 0.4 μm or less, this dimethylformamide solution was measured with a Coulter N4 type submicron particle analyzer.

Intrinsic viscosity, after dissolving the resin pellets in toluene,
The rubber component and the resin component were separated with a centrifuge, and the obtained resin component was measured in toluene at 25 ° C. with a Uderode viscometer.

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

That is, the Izod impact strength (1/4 inch, with notch) was measured according to ASTM D-256 for a molded product obtained by molding at a cylinder temperature of 200 ° C. using an 8 _oz injection molding machine.

Regarding the gloss, a molded article obtained by molding at a cylinder temperature of 200 ° C. using an 8 _oz injection molding machine was measured for a reflective gloss of 60 ° according to ASTM D-523.

As for the coloring property, 0.3 part of micro carbon black was added to 100 parts of the resin, and a sheet piece having a thickness of 2 mm was prepared by injection molding. Was evaluated in 5 levels.

Tensile strength was _measured using an 8 _oz injection molding machine with a cylinder temperature of 200.
The molded product obtained by molding at ℃ was measured according to ASTM D-638.

Examples 1-4, Comparative Examples 1-3 As shown in Table 1, n-butyllithium was used as a catalyst,
By changing the amount of tetrahydrofuran, various polybutadiene rubbers AG having different vinyl bond contents were obtained.

Graft polymerization was carried out by the following method using these polybutadiene rubbers.

That is, a solution prepared by dissolving 7 parts of polybutadiene rubber in 93 parts of styrene was transferred to a reactor equipped with a ribbon blade type stirrer having an internal volume of 10 l, and after adding 150 ppm of t-dodecyl mercaptan to styrene, the rotation speed was 300 rpm, Polymerization was carried out at 118 ° C until the degree of polymerization of styrene reached 30%.

Then, dicumyl peroxide 0.0 per 100 parts of the polymerization solution
5 parts were added, and further 150 parts of water containing 3 parts of tricalcium phosphate as a suspension stabilizer and 0.005 part of sodium dodecylbenzenesulfonate as a surfactant were added and suspended under stirring. This suspension was heated at 120 ° C. for 2 hours, 140 ° C. for 2 hours, and further heated at 160 ° C. for 2 hours to polymerize the suspension.

The obtained bead-like resin was filtered off, washed with water, dried and pelletized with an extruder.

The impact-resistant polystyrene thus obtained was injection-molded to prepare a test piece for measuring physical properties, and its physical properties were evaluated. The results are shown in Table 2.

Comparative Example 4 The procedure of Example 1 was repeated, except that polybutadiene rubber C was used and t-dodecyl mercaptan was changed to 700 ppm with respect to styrene.

Table 2 shows the physical properties of the obtained resin.

As is clear from Tables 1 and 2, in Examples 1 to 4, impact-resistant styrene-based resins (impact-resistant aromatic vinyl-based resins) having excellent coloring properties and an excellent balance between impact resistance and gloss were used.
Is obtained.

On the other hand, in Comparative Example 1, the vinyl bond content in the rubber was too high, resulting in poor impact resistance. In Comparative Example 2, the viscosity of the styrene solution was too low, resulting in a small rubber particle size, resulting in impact resistance. Inferior to.

Further, in Comparative Example 3, the vinyl bond content is too low, resulting in poor colorability, and in Comparative Example 4, the resulting resin has too low intrinsic viscosity, resulting in poor impact resistance and tensile strength.

Examples 5 to 9 and Comparative Examples 5 to 10 As shown in Table 3, polybutadiene rubbers HP were obtained.

The polybutadiene rubbers H to K were obtained by solution polymerization using n-butyllithium as a catalyst,
The polybutadiene rubber L is obtained by using an organoaluminum compound and a nickel compound as a catalyst, and the polybutadiene rubber M is polymerized by using an n-butyllithium catalyst, and then the nickel compound is added to continue the polymerization. The obtained polybutadiene rubbers N to P are n
It is obtained by solution polymerization using butyllithium as a catalyst.

Graft polymerization was carried out in the same manner as in Example 1 using these polybutadiene rubbers, and injection molding was performed in the same manner to prepare test pieces for measuring physical properties, and the physical properties were evaluated. The results are shown in Table 4.

Comparative Example 11 The procedure of Example 1 was repeated, except that polybutadiene rubber J was used and t-dodecyl mercaptan was changed to 700 ppm with respect to styrene.

The physical properties of the obtained resin are shown in Table 4.

As is clear from Tables 3 to 4, in Examples 5 to 9, impact-resistant styrenic resins having excellent colorability and a good balance between impact resistance and gloss were obtained.

On the other hand, in Comparative Examples 5 to 7, since the total vinyl bond content is out of the range of the present invention, the low temperature impact resistance is inferior, and in Comparative Example 8, the ratio of the low vinyl portion and the high vinyl portion is within the range of the present invention. Is inferior in low temperature impact resistance. Further, in Comparative Example 9, the viscosity of the styrene solution is out of the range of the present invention, and thus the impact resistance is inferior. In Comparative Example 10, since there is no high vinyl portion, the coloring property and gloss are inferior. Comparative Example 11 is inferior in mechanical strength (tensile strength) because the intrinsic viscosity is outside the range of the present invention.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain an impact-resistant aromatic vinyl-based resin having excellent impact resistance, gloss, and colorability, which is a household electric appliance component such as a TV, refrigerator, air conditioner, or washing machine, or a personal computer. It is useful for office equipment parts such as word processors, building materials, and miscellaneous goods.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumio Tsutsumi 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (56) Reference JP-A-63-162713 (JP, A) JP Flat 2-191617 (JP, A)

Claims (1)

[Claims] 1. When graft-polymerizing an aromatic vinyl compound in the presence of a butadiene-based (co) polymer, the butadiene-based (co) polymer has (a) a 5 wt% styrene solution viscosity measured at 25 ° C. 55
0-2,000 centipoise, the total vinyl bond content is more than 20 mol% and 70 mol% or less, or (b) the 5 wt% styrene solution viscosity measured at 25 ° C is 200.
~ 2,000 centipoise, the total vinyl bond content is 20 mol% or less, and the vinyl bond content of 15 mol% or less is 30 to 95% by weight, and the vinyl bond content of 25 to 75 mol% is 70%. A mixture or block type containing 5% by weight to 300% by weight of the aromatic vinyl compound in the graft polymerization, and the average particle diameter of the dispersed rubber particles dispersed in the obtained resin is 0.4 to 0.4%. A method for producing an impact-resistant aromatic vinyl resin, which comprises adjusting the intrinsic viscosity of the resin to be in the range of 2.5 μm and 0.7 to 1.4 dl / g.