JP2013213162A - Selectively partially hydrogenated branched conjugated diene polymer, and method for producing vinyl aromatic resin using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a selectively partially hydrogenated branched conjugated diene polymer for an impact resistant vinyl aromatic resin excellent in bale characteristic, glossiness, impact resistance and thermal stability.SOLUTION: A selectively partially hydrogenated branched conjugated diene polymer satisfies (1) to (6) below. (1) A content of a branched component is 70-95 mass%. (2) There are two or more peaks in a GPC molecular weight distribution curve, with a polystyrene equivalent peak molecular weight (A) in a portion with the lowest molecular weight (non-branched component) being 50,000-150,000, of which a ratio to the polystyrene equivalent molecular weight (B) in the highest peak on a side of a higher molecular weight (branched component) than the portion with the lowest molecular weight (non-branched component) (B/A) being 2.5-3.5. (3) A content of a vinyl bonding portion derived from a double bond of the conjugated diene polymer is 10-30%. (4) A hydrogenation rate of the double bond of the conjugated diene polymer is 10-40%. (5) A hydrogenation rate in the vinyl bonding portion is 80-99.0%. (6) A 5% SV at 25°C is 20-50 (cP).

Description

  The present invention relates to a branched conjugated diene polymer that has been partially hydrogenated and a method for producing a vinyl aromatic resin using the branched conjugated diene polymer.

Conventionally, vinyl aromatic resins such as styrene resins and acrylonitrile-styrene resins have been used in various applications because of their excellent moldability, appearance, and rigidity.
In particular, vinyl aromatic resins reinforced with conjugated diene polymer rubber have excellent impact resistance, so they are used for household appliances, office equipment, sports equipment, food packaging applications, etc. Yes.
However, the rubber-modified styrenic resin is improved in impact resistance due to the addition of a rubbery polymer, but there are problems in characteristics such as appearance, such as glossiness and transparency, and thermal stability, Furthermore, it has a practical problem that the operability of the veil of the conjugated diene polymer rubber used as the impact modifier is poor.
In the present specification, the “bale” refers to a rectangular parallelepiped block having a predetermined size obtained by press molding synthetic rubber such as a conjugated diene polymer.

  In view of the above-described problems, conventionally, a conjugated diene polymer rubber obtained by selective hydrogenation of a vinyl group of a conjugated diene portion is radically polymerized with a styrene monomer to provide excellent impact resistance and gloss. And the manufacturing method of the impact-resistant styrene-type resin which improves thermal stability is proposed (refer patent documents 1 thru | or 3).

  In addition, after polymerizing a conjugated diene monomer using an organolithium compound as a polymerization initiator, it is coupled with an alkoxysilane compound to increase the molecular weight, thereby achieving excellent bale moldability and vinyl aromatics. There has been proposed a conjugated diene polymer rubber having improved impact resistance without impairing the appearance of the resin (see Patent Documents 4 to 6).

Japanese Patent Publication No.42-17492 Japanese Patent Publication No. 48-18594 Japanese Patent Publication No. 60-57443 JP-A 64-74209 JP-A-1-74208 JP-A-1-172413

However, the hydrogenated conjugated diene polymer rubbers disclosed in the cited documents 1 to 3 increase the thermal stability of the impact-resistant styrene resin, but have sufficient characteristics for the veil storage property of the conjugated diene polymer rubber. It cannot be said that the conjugated diene polymer rubber is easily dissolved in the styrene monomer at the time of producing the impact-resistant styrene resin.
Further, the conjugated diene polymer rubbers disclosed in the cited documents 4 to 6 are excellent in bale moldability, but in the production of impact-resistant vinyl aromatic resins, bale operability such as adhesion during bale crushing, Furthermore, there is a problem that the thermal stability of the impact resistant vinyl aromatic resin is not sufficient.

  As described above, when added to vinyl aromatic resins such as styrene resins and acrylonitrile-styrene resins, it is possible to impart excellent gloss, impact resistance and thermal stability, and polymers It itself has excellent bale operability such as bale moldability, bale storage stability, adhesion during bale crushing, and good solubility in vinyl aromatic monomers. Satisfactory conjugated diene polymers have not yet been realized.

  The present invention has been made in view of the above-described problems of the prior art, and when added to a vinyl aromatic resin such as a styrene resin or acrylonitrile-styrene resin, has excellent gloss and impact resistance. In addition, heat stability is imparted, and in addition, it itself has excellent bale moldability, storage stability of the bale, adhesion during bale crushing, and good solubility in vinyl aromatic monomers. A selectively partially hydrogenated branched conjugated diene polymer having a bale operability, a mixture of the selected partially hydrogenated branched conjugated diene polymer and a vinyl aromatic monomer, and the selectively partially hydrogenated A mixture of a branched conjugated diene polymer, a vinyl aromatic monomer, and a monomer copolymerizable with the vinyl aromatic monomer is radically polymerized by bulk polymerization, bulk suspension polymerization, or solution polymerization. Impact resistant vinyl aromatic tree And to provide a method of manufacturing.

As a result of diligent studies to solve the above-described problems of the prior art, the present inventors have selected a specific structure obtained by hydrogenating a vinyl bond portion of a conjugated diene polymer having a specific branched structure. The present inventors have found that a partially hydrogenated branched conjugated diene polymer achieves this object, and has led to the present invention.
That is, the present invention is as follows.

[1]
A selective partially hydrogenated branched conjugated diene polymer that satisfies the following requirements (1) to (6).
(1) The branched component of the branched conjugated diene polymer that has been partially hydrogenated is 70 to 95% by mass.
(2) A molecular weight distribution curve measured by GPC of a branched conjugated diene polymer that has been partially hydrogenated, having at least two peaks and having the lowest molecular weight (unbranched component) polystyrene-reduced peak molecular weight (A) is a peak having a peak height of 50,000 to 150,000 and having a peak on the high molecular weight side (branched component) higher than the peak of the lowest molecular weight portion (component not branched). Ratio (B / A) to polystyrene-reduced molecular weight (B) is 2.5 to 3.5.
(3) The content of vinyl bonds derived from the double bond of the conjugated diene polymer of the branched conjugated diene polymer before hydrogenation of the selected part is 10 to 30%.
(4) The hydrogenation rate of the double bond of the conjugated diene polymer of the branched conjugated diene polymer which has been partially hydrogenated is 10 to 40%.
(5) The hydrogenation rate of the vinyl bond part of the branched conjugated diene polymer that has been partially hydrogenated is 80 to 99.0%.
(6) A 5% by mass styrene solution viscosity (5% SV) at 25 ° C. of the branched conjugated diene polymer partially hydrogenated is 20 to 50 centipoise (cP).
[2]
A selectively partially hydrogenated branched conjugated diene polymer obtained using a homogeneous hydrogenation catalyst comprising a metallocene complex of Ti and / or Zr,
The selective partially hydrogenated branched conjugated diene polymer according to [1] above, wherein the content of Ti and / or Zr is 25 ppm by mass or less.
[3]
A mixture of a branched conjugated diene polymer having a partially hydrogenated selected part according to the above [1] or [2] and a vinyl aromatic monomer;
Or
A mixture of the branched hydrogenated branched conjugated diene polymer, a vinyl aromatic monomer, and a monomer copolymerizable with the vinyl aromatic monomer,
Having a step of radical polymerization in any one selected from the group consisting of bulk polymerization, bulk suspension polymerization, and solution polymerization,
Method for producing impact-resistant vinyl aromatic resin.

  According to the present invention, the bale moldability such as storage stability of the bale, excellent adhesion at the time of bale crushing, and excellent bale characteristics such as good solubility in vinyl aromatic monomers are expressed, When added to a vinyl aromatic resin such as styrene resin or acrylonitrile-styrene resin, an impact resistant vinyl aromatic resin that exhibits excellent gloss, impact resistance, and thermal stability is obtained. A partially hydrogenated branched conjugated diene polymer is obtained.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following description, and various modifications can be made within the scope of the gist thereof.

(Branched conjugated diene polymer)
The branched conjugated diene polymer of this embodiment is a branched conjugated diene polymer that is selectively hydrogenated and satisfies the following requirements (1) to (6).
(1) The branched component of the branched conjugated diene polymer that has been partially hydrogenated is 70 to 95% by mass.
(2) A molecular weight distribution curve measured by GPC of a branched conjugated diene polymer that has been partially hydrogenated, having at least two peaks and having the lowest molecular weight (unbranched component) polystyrene-reduced peak molecular weight (A) is a peak having a peak height of 50,000 to 150,000 and having a peak on the high molecular weight side (branched component) higher than the peak of the lowest molecular weight portion (component not branched). The ratio (B / A) to the polystyrene-equivalent molecular weight (B) is 2.5 to 3.5.
(3) The vinyl bond content derived from the double bond of the conjugated diene polymer in the branched conjugated diene polymer before hydrogenation of the selected part is 10 to 30%.
(4) The hydrogenation rate of the double bond of the conjugated diene polymer of the branched conjugated diene polymer that has been partially hydrogenated is 10 to 40%.
(5) The hydrogenation rate of the vinyl bond portion of the branched conjugated diene polymer that has been partially hydrogenated is 80 to 99.0%.
(6) The 5% by mass styrene solution viscosity (5% SV) at 25 ° C. of the branched conjugated diene polymer that has been partially hydrogenated is 20 to 50 centipoise (cP).

[Method for producing branched conjugated diene polymer]
The branched hydrogenated branched conjugated diene copolymer of the present embodiment is polymerized using an organic lithium compound as a polymerization initiator in a hydrocarbon solvent in which at least one conjugated diene monomer coexists with a polar compound. The resulting conjugated diene polymer having an active lithium terminal is reacted with a coupling agent, followed by selective partial hydrogenation with a hydrogenation catalyst.

(Conjugated diene monomer)
As the conjugated diene monomer, conventionally known monomers can be used. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1 , 3-pentadiene, 1,3-heptadiene, 1,3-hexadiene and the like, and these may be used alone or in combination of two or more. In particular, 1,3-butadiene and isoprene are preferable.

(Polymerization initiator)
The organolithium compound used as the polymerization initiator is a compound in which one or more lithium atoms are bonded in the molecule. For example, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert -Butyl lithium, hexamethylene lithium, butadienyl dilithium, isoprenyl dilithium and the like. These may be used alone or in combination of two or more. Further, the organolithium compound may be added in one or more divided portions during the polymerization in the production of the conjugated diene polymer.

(Hydrocarbon solvent)
Examples of the hydrocarbon solvent used for the production of the conjugated diene polymer include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethyl. Hydrocarbon solvents such as cycloaliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene can be used. You may use these 1 type or in mixture of 2 or more types.

(Polar compound)
Polar compounds are used as microstructure modifiers for conjugated diene units.
For example, dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, trimethylamine, triethylamine, tetramethylethylenediamine, triphenylphosphine, hexamethylphosphoramide, (2,2-bis (2-oxolanyl) propane, etc. Can be mentioned.
The microstructure (ratio of cis, trans, vinyl) of the conjugated diene polymer before selective partial hydrogenation described later can be controlled by using a polar compound or the like.

(Polymerization temperature, time, atmosphere, pressure)
The polymerization temperature for producing the conjugated diene polymer is preferably -10 to 150 ° C, more preferably 30 to 120 ° C. The time required for the polymerization varies depending on the conditions, but is preferably within 48 hours, more preferably 0.5 to 10 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is carried out within a range of pressure sufficient to maintain the monomer and solvent in the liquid phase within the above polymerization temperature range. Furthermore, it is preferable that impurities that inactivate the catalyst and the living polymer, for example, water, oxygen, carbon dioxide gas, and the like are not mixed in the polymerization system.

(Coupling agent)
Examples of the coupling agent include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, ethyltrioxysilane, tetrabutoxysilane, and tetraphenoxysilane. These may be used alone or in combination of two or more. Preferred coupling agents include tetramethoxysilane and tetraethoxysilane.
When these coupling agents are used, a tribranched component is mainly obtained.

The amount of these coupling agents used mainly to obtain a tri-branched component is 0.7 equivalent or more with respect to 1 mol of the organolithium compound used when producing a conjugated diene polymer having an active lithium terminal. And more preferably in the range of 0.75 equivalents to 0.95 equivalents.
By using a coupling agent that mainly yields a three-branched component, as will be described later, the polystyrene-reduced peak molecular weight (A) of the lowest molecular weight part (component not branched) and the peak of the lowest molecular weight part The ratio (B / A) with the polystyrene equivalent molecular weight (B) of the peak portion having the highest peak height, which is the peak on the high molecular weight side (branched component), is controlled to 2.5 to 3.5. Can do.
In addition, when the addition amount of the coupling agent is excessive, the ratio (B / A) with the polystyrene-equivalent molecular weight (B) of the peak portion having the highest peak height is less than 2.5, so that it is bifurcated. If the amount of the component is increased and the addition amount is too small, the coupling rate is lowered. Therefore, as described above, 1 mol of the organolithium compound used when producing a conjugated diene polymer having an active lithium terminal. The range of 0.75 equivalent to 0.95 equivalent is preferable.

  The reaction time of the conjugated diene polymer having an active lithium terminal and the coupling agent can be adjusted over a wide range, but is preferably 1 minute to 60 minutes, more preferably 1 minute to 30 minutes. The coupling agent may be used alone or dissolved in a solvent. When a solvent is used, a hydrocarbon solvent that is inactive with respect to active lithium is used. Examples of the hydrocarbon solvent include benzene, toluene, cyclohexane, n-hexane and the like. Although there is no restriction | limiting in particular about the addition method of the said coupling agent, The method of adding in a batch type or a continuous system is generally used.

  The reaction temperature between the conjugated diene polymer having an active lithium terminal and the coupling agent is preferably in the range of 50 to 130 ° C, more preferably 80 to 110 ° C. When the reaction temperature exceeds 130 ° C., the coupling efficiency is remarkably lowered and a desired branched conjugated diene polymer cannot be obtained. If it is less than 50 degreeC, the reactivity with this compound falls remarkably and is not preferable.

The active lithium terminal of the conjugated diene polymer can be stopped with a coupling agent or a stopper made of a predetermined alcohol.
The addition amount of the terminator is preferably 0.9 to 1.1 equivalents, more preferably 0.95 to 1.05 equivalents with respect to lithium at the end of active lithium.
The closer the addition amount of this terminator is to 1.0 equivalent to the lithium at the end of the active lithium, the smaller the addition amount of the hydrogenation catalyst described above, and in particular, (3) Ti, Ru, Rh, Zr described later. In the case of using a homogeneous hydrogenation catalyst containing a metallocene complex of Ti and / or Zr among homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds such as The content of Ti and / or Zr in the hydrogenated branched conjugated diene polymer can be reduced to 25 ppm by mass or less.
In addition, when the addition amount of a terminator is less than 90 equivalent with respect to lithium, or when it exceeds 1.1 equivalent, it will be necessary to increase the addition amount of the hydrogenation catalyst mentioned later.

(Selective hydrogenation)
The selected partially hydrogenated branched conjugated diene polymer of the present embodiment can be obtained by selectively hydrogenating the double bond of the branched conjugated diene polymer.
“Selective hydrogenation” refers to hydrogenation of a predetermined unsaturated portion preferentially over other unsaturated portions. For example, when the branched conjugated diene polymer is branched butadiene, The selective hydrogenation of the 1,2 bond units prior to the unsaturated 1,4 bond units. More specifically, the unsaturated 1,2 bond units are preferentially hydrogenated, and the unsaturated 1,4 bond units are hydrogenated little by little at the same time. The hydrogenation rate of the bond unit (vinyl bond part) is selectively hydrogenated from 80 to 99.0%.
The hydrogenation catalyst is not particularly limited and is conventionally known (1) A supported heterogeneous hydrogen catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. (2) So-called Ziegler type hydrogenation catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organic aluminum, (3) Ti, Ru Homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds such as Rh and Zr are used.
Specific examples of the hydrogenation catalyst include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-337970, Japanese Patent Publication No. 1-53851, The hydrogenation catalyst described in Japanese Utility Model Publication No. 2-9041 can be used. Preferred hydrogenation catalysts include a mixture with a titanocene compound and / or a reducing organometallic compound.
The hydrogenation catalyst is a catalyst that can selectively hydrogenate unsaturated 1,2 bond units prior to unsaturated 1,4 bond units, and produces a selectively partially hydrogenated branched conjugated diene polymer of this embodiment. This is preferable.
As the titanocene compound, compounds described in JP-A-8-109219 can be used, and specifically, (substituted) such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. And compounds having at least one ligand having a cyclopentadienyl skeleton, an indenyl skeleton or a fluorenyl skeleton. Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.
Among the homogeneous hydrogenation catalysts such as (3) so-called organometallic complexes such as organometallic compounds such as Ti, Ru, Rh and Zr, a homogeneous hydrogenation catalyst containing a metallocene complex of Ti and / or Zr, It is preferable from the viewpoint of good hydrogenation activity and easy preparation, and from the viewpoint of economy.

The hydrogenation reaction is preferably carried out in a temperature range of 0 to 200 ° C, more preferably 30 to 150 ° C.
The pressure of hydrogen used in the hydrogenation reaction is preferably 0.1 to 15 Mpa, more preferably 0.2 to 10 Mpa, and still more preferably 0.3 to 5 Mpa. The hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. For the hydrogenation reaction, any of a batch process, a continuous process, or a combination thereof can be used.

The solution of the selected partial hydrogenated branched conjugated diene polymer obtained as described above can be separated from the solution by removing the catalyst residue, if necessary.
Separation of the solvent is carried out by putting the branched conjugated diene polymer solution into hot water with stirring and removing the solvent by steam stripping.
Stabilizers such as various phenol stabilizers, phosphorus stabilizers, sulfur stabilizers and amine stabilizers can be added to the recovered polymer.

[Structure and physical properties of branched conjugated diene polymer]
((1) Content of branched component of selected partially hydrogenated branched conjugated diene polymer)
The content of the branched component of the branched conjugated diene polymer that has been partially hydrogenated in this embodiment is 70 to 95% by mass. Preferably it is 80-95 mass%, More preferably, it is 85-95 mass%.
If the branched component is less than 70% by mass, the bale of the branched conjugated diene polymer tends to cold flow, and the bale storage stability tends to deteriorate. Further, when the veil is pulverized during the production of the impact-resistant vinyl aromatic resin described later, the branched conjugated diene polymer is liable to adhere to peripheral devices, which is not preferable from the viewpoint of product quality. On the other hand, when the branched component exceeds 95% by mass, the thermal stability of the branched conjugated diene polymer is inferior.
In order to adjust the branched component of the branched conjugated diene polymer to 70 to 95% by mass, it is effective to appropriately adjust the amount used according to the type of the coupling agent described above.
Content of a branched component is synonymous with a coupling rate, and can be measured by the method as described in the Example mentioned later.

((2) number of peaks in GPC molecular weight distribution curve, peak molecular weight, predetermined peak molecular weight ratio)
The selected partial hydrogenated branched conjugated diene polymer of this embodiment has at least two peaks in the molecular weight distribution curve measured by gel permeation chromatography (GPC), and has the lowest molecular weight portion (branched). The polystyrene (PS) equivalent peak molecular weight (A) of the component not allowed to be) is 50,000 to 150,000, and on the higher molecular weight side (branched component) than the peak of the lowest molecular weight part (component not branched). The ratio (B / A) to the polystyrene (PS) PS-converted molecular weight (B) of the peak portion having the highest peak height is 2.5 to 3.5 (mainly composed of three branched components), preferably Is 2.6 to 3.4, more preferably 2.7 to 3.3.
When the (B / A) ratio is less than 2.5, that is, the main component is a bibranched component, the bale of the branched conjugated diene polymer that has been partially hydrogenated tends to cold flow, and the bale storage stability deteriorates. Tend to. Further, when producing the impact-resistant vinyl aromatic resin described later, when the veil is pulverized, the branched conjugated diene polymer is liable to adhere to the peripheral device, which is a cause of contamination and is not preferable from the viewpoint of product quality.
On the other hand, if the (B / A) ratio exceeds 3.5, the rubber particle diameter becomes larger and the particle size distribution becomes wider during the production of the impact-resistant vinyl aromatic resin described later, impact resistance and gloss The balance of sex deteriorates, which is not preferable.
In the branched hydrogenated conjugated diene polymer of the present embodiment, (A) is preferably 80,000 to 150,000, more preferably 90 to 120,000, and (B) is preferably 240,000 to 450,000. More preferably, it has a peak at a molecular weight in terms of PS of 270,000 to 360,000.
About the measuring method of a peak molecular weight and a peak molecular weight ratio, it can measure by the method as described in the Example mentioned later.

((3) Vinyl bond content derived from double bond of conjugated diene polymer of branched conjugated diene polymer before selective partial hydrogenation)
The vinyl bond content derived from the double bond of the conjugated diene polymer of the branched conjugated diene polymer before hydrogenation of the branched conjugated diene polymer selectively hydrogenated in this embodiment is 10 to 30%. It is. Preferably it is 12-25%, More preferably, it is 14-20%.
The microstructure (ratio of cis, trans, vinyl) of the branched conjugated diene polymer before selective partial hydrogenation can be controlled by the use of the polar compounds described above. When 1,3-butadiene is used as the conjugated diene, the 1,2-vinyl bond content is 10 to 30%, preferably 12 to 25%. When isoprene is used as the conjugated diene, When 3-butadiene and isoprene are used, the total vinyl bond content of 1,2-vinyl bonds and 3,4-vinyl bonds is 10-30%, preferably 12-25%.
When the 1,2-vinyl bond content or the total amount of the 1,2-vinyl bond content and the 3,4-vinyl bond content is less than 10%, the impact-resistant vinyl aromatic resin described later is produced. , The solubility in the vinyl aromatic monomer is inferior, and the graft efficiency is further deteriorated. On the other hand, if it exceeds 30%, there is a problem in controlling the rubber particle diameter during the production of an impact-resistant vinyl aromatic resin, which will be described later, and the glossiness is deteriorated.
The vinyl bond content derived from the double bond of the conjugated diene polymer in the branched conjugated diene polymer before selective partial hydrogenation can be measured by the method described in the examples described later.

((4) Hydrogenation rate of double bond of conjugated diene polymer of branched conjugated diene polymer hydrogenated selectively)
The hydrogenation rate of the double bond of the conjugated diene polymer of the branched conjugated diene polymer subjected to selective partial hydrogenation of this embodiment is 10 to 40%. Preferably it is 20 to 38%, more preferably 25 to 36%.
In order to control the hydrogenation rate within the above numerical range, the amount of hydrogen is calculated from the amount of conjugated diene in the branched conjugated diene polymer, and the hydrogenation rate of double bonds in the branched conjugated diene polymer is confirmed. If the desired hydrogenation rate is obtained, the hydrogen supply may be stopped. If the predetermined hydrogenation rate is not achieved, hydrogen may be further added to finely adjust the hydrogenation rate. .
When the hydrogenation rate is less than 10%, the thermal stability of the impact-resistant vinyl aromatic resin described later is lowered.
When the hydrogenation rate exceeds 40%, the solubility in the vinyl aromatic monomer is inferior when the impact-resistant vinyl aromatic resin described later is produced.
The hydrogenation rate of the branched conjugated diene polymer that has been partially hydrogenated can be measured by a nuclear magnetic resonance apparatus (NMR).

((5) Hydrogenation rate of vinyl bond part of selected conjugated diene polymer partially hydrogenated)
The hydrogenation rate of the vinyl bond portion of the selected partially hydrogenated branched conjugated diene polymer of this embodiment is 80 to 99.0%. Preferably it is 85 to 98%, more preferably 90 to 98%.
In order to control the hydrogenation rate of the vinyl bond part within the above numerical range, the amount of hydrogen is calculated from the amount of conjugated diene in the branched conjugated diene polymer, and the vinyl bond of the branched conjugated diene polymer is calculated from the amount of hydrogen. If the desired hydrogenation rate is obtained, the hydrogen supply may be stopped. If the predetermined hydrogenation rate is not achieved, hydrogen is further added. The hydrogenation rate may be finely adjusted.
When the hydrogenation rate of the vinyl bond portion is less than 80%, the thermal stability and impact resistance of the impact-resistant vinyl aromatic resin described later are lowered.
When the hydrogenation rate exceeds 99%, the solubility in the vinyl aromatic monomer is inferior when the impact-resistant vinyl aromatic resin described later is produced.
The hydrogenation rate of the vinyl bond portion of the branched conjugated diene polymer that has been partially hydrogenated can be measured by the method described in the examples described later.

((6) Viscosity of 5% by weight styrene solution (5% SV) at 25 ° C. of a branched conjugated diene polymer partially hydrogenated)
The 5 mass% styrene solution viscosity (5% SV) at 25 ° C. of the branched conjugated diene polymer selectively hydrogenated in this embodiment is 20 to 50 cP. Preferably it is 20-45 cP, More preferably, it is 23-40 cP.
When the SV is less than 20 cP, the bale of the branched conjugated diene polymer that has been partially hydrogenated tends to cold flow and the bale storage stability is poor. Furthermore, at the time of producing an impact-resistant vinyl aromatic resin composition, which will be described later, when the veil is crushed, the polymer rubber is liable to adhere to peripheral devices, which is a cause of contamination and is not preferable from the viewpoint of product quality.
When 5% SV exceeds 50 cP, the solubility in the vinyl aromatic monomer is inferior when the impact-resistant vinyl aromatic resin described later is produced. Furthermore, the glossiness of the impact resistant vinyl aromatic resin described later deteriorates.

[Method for producing impact-resistant vinyl aromatic resin using branched conjugated diene polymer]
A mixture of the above-described partially hydrogenated branched conjugated diene polymer and a vinyl aromatic monomer, or a partially partially hydrogenated branched conjugated diene polymer and a vinyl aromatic monomer, and the vinyl By subjecting a mixture of an aromatic monomer and a copolymerizable monomer to radical polymerization by any polymerization method selected from the group consisting of bulk polymerization, bulk suspension polymerization, and solution polymerization, a vinyl aromatic unit is obtained. It is possible to produce an impact-resistant vinyl aromatic resin having good solubility in a polymer, excellent bale operability, and excellent gloss, impact resistance, and thermal stability. As a manufacturing method, block polymerization and block suspension polymerization are preferable. Embodiments of these polymerization methods are described below.

  As the vinyl aromatic monomer, conventionally known monomers can be used. For example, styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p -Tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, o-chlorostyrene, p-chlorostyrene, m-chlorostyrene, 2-methyl-1,4-dichlorostyrene, vinylnaphthalene, etc. Is mentioned. Of these, styrene is preferred. These vinyl aromatic compounds can be used alone or in combination of two or more.

  As the monomer copolymerizable with the vinyl aromatic monomer, conventionally known monomers can be used, for example, nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, methacrylic acid, and the like. Examples include (meth) acrylic acid ester monomers such as methyl ester and acrylic acid methyl ester, α, β-unsaturated acid monomers such as acrylic acid, methacrylic acid, and maleic anhydride, and phenylmaleimide. Among these, nitrile monomers, (meth) acrylic acid ester monomers, α, β-unsaturated acid monomers are preferable, and nitrile monomers are more preferable. The monomers copolymerizable with these vinyl aromatic monomers can be used alone or in combination of two or more.

  The use ratio of the vinyl aromatic monomer and the monomer copolymerizable with the vinyl aromatic monomer is the weight of the vinyl aromatic compound and the monomer copolymerizable with the vinyl aromatic monomer. The ratio is preferably 50 to 100: 50 to 0, more preferably 55 to 95:45 to 5, and still more preferably 60 to 90:40 to 10.

  Generally in bulk polymerization, a rubbery polymer such as the above-described partially hydrogenated branched conjugated diene polymer of this embodiment is dissolved in a vinyl aromatic monomer such as styrene, and if necessary, Add diluents such as toluene and ethylbenzene, internal lubricants such as liquid paraffin and mineral oil, antioxidants, mercaptans and α-methylstyrene dimer chain transfer agents, etc. At 200 ° C., the polymerization operation is continued until the polymerization of the vinyl aromatic monomer is substantially completed at a lower temperature in the initiator polymerization, that is, at 60 to 170 ° C.

In the case of the initiator polymerization, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane is used as a polymerization initiator. Peroxyketals such as, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, dialkyl peroxides such as dicumyl peroxide, benzoyl peroxide, Diacyl peroxides such as m-toluoyl peroxide and lauroy peroxide, di-myristyl peroxydicarbonate, diisopropyl peroxydicarbonates, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxyacetate, di-tert- Butyl peroxyisophthalate, tert-butyl Peroxyesters of peroxybenzoates, ketone peroxides such as cyclohexanone peroxide, methyl ethyl ketone peroxide, hydroperoxides such as p-menta hydroperoxide, tert-butyl hydroperoxide, cumene hydroperoxide, azobis Azo compounds such as isobutyronitrile and azobiscyclohexane are used.
These are used alone or in combination of two or more. Further, chain transfer agents such as mercaptans, α-methylstyrene linear dimer and terpinolene can be used as necessary.

  In bulk polymerization of the impact-resistant vinyl aromatic resin, 1 to 5 parts by mass of a known internal lubricant such as liquid paraffin may be added to 100 parts by mass of the vinyl aromatic monomer.

  After the polymerization of the impact-resistant vinyl aromatic resin, when the polymer contains a small amount (1 to 20%) of an unreacted vinyl aromatic monomer such as styrene, the unreacted vinyl It is preferable to remove the aromatic monomer by a known method, for example, a method such as removing with an extruder designed for the purpose of removing under reduced pressure or removing volatile matter.

  During such bulk polymerization, stirring is preferably performed as necessary. The stirring is preferably stopped or relaxed after the conversion rate of the vinyl aromatic monomer, for example, styrene to a polymer, that is, the polymerization rate of the vinyl aromatic monomer reaches 30% or more. . Excessive stirring may reduce the strength of the resulting impact-resistant vinyl aromatic resin. Further, if necessary, polymerization may be performed in the presence of a small amount of a diluent such as toluene or ethylbenzene, and these diluents may be removed by heating together with an unreacted vinyl aromatic monomer at a stage where the polymerization rate is 60% or more. .

In the bulk / suspension polymerization of the vinyl aromatic resin, the first half reaction is first performed by bulk polymerization, and the second half reaction is performed by suspension polymerization.
That is, a vinyl aromatic monomer of a branched conjugated diene polymer, such as a solution of styrene, is heat-polymerized or catalyzed in a non-catalytic manner in the same manner as in the bulk polymerization described above, The body, for example, preferably 50% by weight or less, more preferably 10 to 40% by weight of styrene is partially polymerized. This is the first half block polymerization.
This partially polymerized mixture is then dispersed with stirring in an aqueous medium in the presence of a suspension stabilizer or both and a surfactant, and the latter half of the reaction is completed by suspension polymerization and washed. , Dried and pelletized or powdered if necessary.

  The production method of the impact-resistant vinyl aromatic resin described above can be modified and improved conventionally.

The impact resistant vinyl aromatic resin of the present embodiment is excellent in impact resistance and appearance characteristics, and can be used as a wide variety of practically useful products by processing methods such as injection molding and extrusion molding.
Furthermore, when processing, antioxidants, UV absorbers, mold release agents, fillers, flame retardants, and other thermoplastic resins such as general-purpose polystyrene, methacrylic resin, polyphenylene ether, polycarbonate, and styrene / butadiene block are used. It may be mixed with a polymer resin, a methyl methacrylate / styrene copolymer resin, a maleic anhydride / styrene copolymer resin, or the like.

(Application of impact resistant vinyl aromatic resin)
The impact-resistant vinyl aromatic resin of the present embodiment is excellent in appearance, impact resistance, and thermal stability and can be used in a wide range of applications.
For example, household appliances such as washing machines, air conditioners, refrigerators, AV equipment, personal computers, OA equipment, toys, food trays, packaging containers, cosmetic containers, sheets and other miscellaneous goods, automobile interior and exterior, structural materials such as housing materials, medical It can be used for appliance materials, optical materials, telephones, mobile phones and the like.

  Hereinafter, specific examples and comparative examples will be specifically described, but the present invention is not limited thereto.

[Characteristics of conjugated diene polymer and selectively hydrogenated conjugated diene polymer]
<(1) Ratio of vinyl bond in conjugated diene monomer unit (vinyl bond content)>
Measurement was performed by proton NMR using a JNME CA500 (500 MHz) NMR apparatus manufactured by JEOL Ltd.

<(2) Measurement of coupling rate and peak molecular weight>
GPC (The apparatus is HLC-8320GPC EcoSEC manufactured by Tosoh Corporation, the column uses two TSKgel SuperMultipores, the solvent uses tetrahydrofuran, and the measurement conditions are a temperature of 35 ° C., a flow rate of 0.4 mL / min, and a sample concentration of 0.1% by mass. ), And the coupling rate is calculated from the ratio of the peak area not coupled (peak on the low molecular weight side) to the peak area coupled (peak on the high molecular weight side). Calculated.
The peak molecular weight was calculated | required from the obtained GPC chromatogram using the calibration curve created using the commercially available standard monodisperse polystyrene with known molecular weight.
Polystyrene conversion peak molecular weight (A) on the low molecular side (uncoupled part: peak of the lowest molecular weight part) of the molecular weight distribution curve of the conjugated diene polymer and the high molecular side (coupling part) of the molecular weight distribution curve of the conjugated diene polymer : A peak having a higher molecular weight than a peak of the lowest molecular weight part and a peak part having the highest peak height) and a polystyrene conversion peak molecular weight (B) are calculated, and each peak molecular weight (A ) And (B) were calculated.

<(3) Measurement of Mooney viscosity>
Using a MOONEY VISCOMETER SMV-202 manufactured by Shimadzu Corporation, ML1 + 4 (100 ° C.), which is a torque after 1 minute of residual heat at 100 ° C. and 4 minutes after driving, was measured.

<(4) Viscosity of 5% by weight styrene solution (5% SV)>
5% SV is obtained by dissolving 5 g of a selectively partially hydrogenated branched conjugated diene polymer in 95 g of styrene monomer over 2 hours to obtain a solution. The viscosity was measured using a kettle viscometer and expressed in centipoise (cP).

<(5) Measurement of shape change rate>
A 1 kg load is placed on a bale-like conjugated diene polymer having a length of 4 cm, a width of 4 cm, and a height of 5 cm (H0), or a selectively hydrogenated conjugated diene polymer, and allowed to stand at 23 ° C. for 60 minutes. The height (Ht) (mm) of the polymer was measured.
The shape change rate was evaluated by the following formula.
It was evaluated that the larger this value, the easier the conjugated diene copolymer rubber is deformed.
Shape change rate (%) = (H0−Ht) × 100 / H0

<(6) Measurement of hydrogenation rate of 1,2-vinyl bond after selective hydrogenation>
The unsaturated bond unit amount and the saturated bond unit amount of the 1,2-vinyl bond part of the selectively hydrogenated conjugated diene polymer were measured by proton NMR using a JNME CA500 (500 MHz) NMR apparatus manufactured by JEOL Ltd.
The hydrogenation rate of the 1,2-vinyl bond part can be calculated by the unsaturated bond unit amount of the 1,2-vinyl bond part / (total amount of unsaturated bond units + total amount of saturated bond units) × 100.

<(7) Total hydrogenation rate>
Unsaturated bond unit amount of 1,2-vinyl bond part, unsaturated bond unit quantity of 1,4-butadiene part, saturated bond unit quantity saturated with 1,2-vinyl bond part, 1,4-butadiene bond part And the total hydrogenation rate is determined by the total unsaturated bond unit amount after hydrogenation of the 1,2-vinyl bond portion and the 1,4-butadiene bond portion / (total unsaturation). Bond unit amount + total saturated bond unit amount) × 100.

<(8) Measurement of solubility of selected hydrogenated conjugated diene polymer in vinyl aromatic monomer>
The selected hydrogenated conjugated diene polymer (total 5 g) having a size of about 5 mm square is put in 95 g of styrene and reciprocally shaken (shaking number 200 times / min) at 25 ° C. in a shaking bath BW400 manufactured by Yamato Scientific. Then, the time (hr) until the selectively hydrogenated conjugated diene polymer was completely dissolved was measured.
When the dissolution time was 10 hours or longer, it was judged that the polymerization process of the impact-resistant vinyl aromatic resin would be hindered.

<(9) Adhesiveness during pulverization (collection rate of pulverized polymer)>
The selected hydrogenated conjugated diene polymer cut to a thickness of 20 to 30 mm was pulverized by putting a total of 200 g into a cutting mill (Retsch, SM100) equipped with a 4 mm screen with a standard type hopper, and using a sample receiver. It collected and the collection rate was computed.
When the collection rate was 90% or less, it was judged that the accumulated matter in the pulverizer adhered due to heat during pulverization and stayed for a long time, which could cause deterioration (gelation).

<(10) Measurement of solubility of selected hydrogenated conjugated diene polymer in a mixture of vinyl aromatic monomer and vinyl cyanide monomer>
A selective hydrogenated conjugated diene polymer (total 5.3 g) having a size of about 5 mm square is put in a mixture of 75 g of styrene and 25 g of acrylonitrile, and is shaken reciprocally at 25 ° C. in a shaking bath BW400 manufactured by Yamato Scientific. 200 times / minute), and the time until the selectively hydrogenated conjugated diene polymer rubber was completely dissolved was measured.
When the dissolution time was 10 hours or longer, it was judged that the polymerization process of the impact-resistant vinyl aromatic resin would be hindered.

[Preparation of hydrogenation catalyst used in hydrogenation reaction]
<(1) Hydrogenation catalyst I>
Charge 1 liter of dried and purified cyclohexane to a nitrogen-substituted reaction vessel, add 100 mmol of dichlorobis (η5-2,4-cyclopentadien-1-yl) titanium, and contain 200 mmol of trimethylaluminum with thorough stirring. -A hexane solution was added and reacted at room temperature for about 3 days to obtain hydrogenation catalyst I.
<(2) Hydrogenation catalyst II>
A reaction vessel purged with nitrogen was charged with 2 liters of dried and purified cyclohexane, 40 mmol of bis (η5-cyclopentadienyl) titanium di- (p-tolyl) and 1,2-polybutadiene having a molecular weight of about 1,000 (1 , 2-vinyl bond content: about 85%) After dissolving 150 grams, a cyclohexane solution containing 60 mmol of n-butyllithium was added and reacted at room temperature for 5 minutes, and n-butanol was immediately added and stirred at room temperature. The hydrogenation catalyst II was obtained.

(Preparation of polymer)
(Preparation of polymer 1)
Using a polymerization tank having an internal volume of 30 liters and equipped with a stirring blade and a jacket, a cyclohexane solution of 1,3-butadiene having a concentration of 15% by mass containing 100 ppm of 1,2-butadiene per monomer was charged. 0.12 parts by mass of n-butyllithium per part by mass was added, and polymerization was performed with stirring at a peaking temperature of 90 ° C. to obtain a living polymer solution.
Further, 0.95 equivalent of tetramethoxysilane / cyclohexane solution is added to the feed lithium to perform a coupling reaction, the polymerization of the conjugated diene polymer is terminated, and the polymer solution for analysis of the polymer before hydrogenation Were collected.
Thereafter, 25 mass ppm of titanium as the above-mentioned hydrogenation catalyst I was added to the obtained copolymer in the polymerization tank as titanium with respect to the weight of the copolymer, and the hydrogenation rate was 0.7 MPa at a hydrogen pressure of 70 ° C. Hydrogenation reaction was carried out until it reached about 20%.
After completion of the reaction, an equivalent amount of methanol was added to the feed titanium, and the polymer was extracted from the reactor.
Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer based on the weight of the polymer. Furthermore, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 1.

(Preparation of polymers 2, 3, 6, 7)
Except that the hydrogenation reaction was carried out until a predetermined hydrogenation rate, the same polymerization operation as that of the polymer 1 was carried out, and octadecyl-3- (3,5-di-t-butyl-4 was used as a stabilizer. -Hydroxyphenyl) propionate was added in an amount of 0.3% by weight based on the weight of the polymer.
Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain polymers 2, 3, 6, and 7, respectively.

(Preparation of polymer 4)
Using a polymerization tank having an internal volume of 30 liters and equipped with a stirring blade and a jacket, a cyclohexane solution of 1,3-butadiene having a concentration of 15% by mass containing 100 ppm of 1,2-butadiene per monomer was charged. 0.12 parts by mass of n-butyllithium per part by mass was added, and polymerization was performed with stirring at a peaking temperature of 90 ° C. to obtain a living polymer solution.
Further, 0.8 equivalent of tetraethoxysilane / cyclohexane solution is added to the feed lithium to perform a coupling reaction, the polymerization of the conjugated diene polymer is terminated, and the polymer solution for analysis of the polymer before hydrogenation Were collected.
Thereafter, the above-mentioned hydrogenation catalyst II was added to the obtained copolymer in the polymerization tank at 25 mass ppm as titanium with respect to the weight of the copolymer, and the hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 70 ° C. Went.
After completion of the reaction, an equivalent amount of methanol was added to the feed titanium, and the polymer was extracted from the reactor.
Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer based on the weight of the polymer.
Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 4.

(Preparation of polymer 5)
Using a polymerization tank having an internal volume of 30 liters and equipped with a stirring blade and a jacket, a cyclohexane solution of 1,3-butadiene having a concentration of 15% by mass containing 100 ppm of 1,2-butadiene per monomer was charged. 0.12 parts by mass of n-butyllithium per part by mass was added, and polymerization was performed with stirring at a peaking temperature of 90 ° C. to obtain a living polymer solution.
Further, 0.95 equivalent of tetramethoxysilane / cyclohexane solution was added to the feed lithium to carry out a coupling reaction, the polymerization of the conjugated diene polymer was terminated, and the polymer was extracted from the reactor.
Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer based on the weight of the polymer.
Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 5.

(Preparation of polymer 8)
Using a polymerization tank having an internal volume of 30 liters and equipped with a stirring blade and a jacket, a cyclohexane solution of 1,3-butadiene having a concentration of 15% by mass containing 100 ppm of 1,2-butadiene per monomer was charged. 0.12 parts by mass of n-butyllithium per part by mass was added, and polymerization was performed with stirring at a peaking temperature of 90 ° C. to obtain a living polymer solution.
Further, 0.95 equivalent of tetramethoxysilane / cyclohexane solution is added to the feed lithium to perform a coupling reaction, the polymerization of the conjugated diene polymer is terminated, and the polymer solution for analysis of the polymer before hydrogenation Were collected.
Thereafter, 100 mass ppm of the hydrogenation catalyst I described above as titanium is added to the copolymer obtained in the polymerization tank as titanium with respect to the weight of the copolymer, and hydrogenation reaction is performed at a hydrogen pressure of 0.7 MPa and a temperature of 70 ° C. went.
After completion of the reaction, an equivalent amount of methanol was added to the feed titanium, and the polymer was extracted from the reactor.
Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer based on the weight of the polymer.
Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 8.

(Preparation of polymer 9)
Using a polymerization tank having an internal volume of 30 liters and equipped with a stirring blade and a jacket, a cyclohexane solution of 1,3-butadiene having a concentration of 15% by mass containing 100 ppm of 1,2-butadiene per monomer was charged. 0.12 parts by mass of n-butyllithium per part by mass was added, and polymerization was performed at a peaking temperature of 90 ° C. with stirring to obtain a living polymer solution.
Further, 0.65 equivalent of tetramethoxysilane / cyclohexane solution was added to the feed lithium to perform a coupling reaction, and then 0.4 equivalent of methanol was added to the feed lithium to complete the polymerization of the conjugated diene polymer. A polymer solution was collected for analysis of the polymer before hydrogenation.
Thereafter, the above-mentioned hydrogenation catalyst II was added to the obtained copolymer in the polymerization tank at 25 mass ppm as titanium with respect to the weight of the copolymer, and the hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70 ° C. went.
After completion of the reaction, an equivalent amount of methanol was added to the feed titanium, and the polymer was extracted from the reactor.
Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer based on the weight of the polymer.
Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 9.

(Preparation of polymer 10)
In a polymerization tank having an internal volume of 10 liters and equipped with a stirring blade and a jacket, an n-hexane solution of 1,3-butadiene having a concentration of 15% by mass from the bottom is simultaneously added at a rate of 300 ml / min. 0.20 parts by mass of n-butyllithium was continuously fed per unit.
Polymerization was performed by mixing and stirring at a rotation speed of 150 rpm and a polymerization temperature of 90 ° C., and the overflowing living polymer solution was introduced into a Noritake static mixer (18 elements). Before the static mixer, an equivalent amount of ethanol was added to the feed lithium and further introduced into a hydrogenation reactor having an internal volume of 4 liters.
Before the hydrogenation reactor, the above-mentioned hydrogenation catalyst II was added in an amount of 25 mass ppm as titanium with respect to the weight of the copolymer, and hydrogenated so as to achieve a predetermined hydrogenation rate at a hydrogenation temperature of 100 ° C. with high-speed stirring. Selective hydrogenation was continuously performed while controlling the feed amount.
To the solution exiting the hydrogenation reactor, an equivalent amount of methanol to feed titanium is added, and then octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is added as a stabilizer. 0.3 mass% was added with respect to the weight of coalescence. Further, the obtained polymer solution was dropped into hot water with stirring, the solvent was removed by steam stripping, and then heated and dried to obtain a polymer 10.

  Table 1 below shows the properties of the polymers 1 to 10 prepared as described above before hydrogenation and after selective partial hydrogenation.

[Examples 1 to 4], [Comparative Examples 1 to 5]
Shapes of Polymers 1 to 4 (Examples 1 to 4), Polymers 5 to 6 (Comparative Examples 1 and 2), Polymer 7 (Comparative Example 3), and Polymers 9 to 10 (Comparative Examples 4 to 5) Table 2 shows the measurement results of the rate of change, the adhesion / retention rate during pulverization, the solubility in the styrene monomer solution, and the solubility in the mixed solution of styrene and acrylonitrile.

As shown in Table 2 above, it was found that the polymers 1 to 4 (Examples 1 to 4) had a shape change rate of 30% or less and a low adhesion and retention rate during pulverization.
The polymer 5 (Comparative Example 1) that has not been selectively hydrogenated and the polymer 6 (Comparative Example 2) that has a selective hydrogenation rate of 5.2% have a large shape change rate and are likely to adhere and stay during grinding. I understood.
Moreover, it turned out that the polymer 9 (comparative example 4) with a low coupling rate and the polymer 10 (comparative example 5) which is not coupled also have a large shape change rate, and are easy to adhere and stay at the time of a grinding | pulverization.
Polymer 7 (Comparative Example 3) in which the total hydrogenation rate after selective hydrogenation is 40% or more and the hydrogenation rate of the 1,2-vinyl bond part exceeds 99.0% has a small shape change rate, It was found that the adhesion and retention during pulverization was small and good, but the solubility in styrene monomer and the like was very poor.

[Characteristics of impact-resistant vinyl aromatic resin]
As shown in [Examples 5 to 11] and [Comparative Examples 6 to 11] described later, impact-resistant vinyl aromatic resins were prepared, and the following characteristics were measured and evaluated.
<Average rubber particle size>
The impact-resistant vinyl aromatic resin is dissolved in dimethylformamide, and only the polystyrene resin part that forms the matrix in the resin is dissolved, and a part of the solution is subjected to a particle size distribution (laser diffraction / (Scattering type) A measurement device, LA-920 type, was used by measuring the dispersion in the solvent dimethylformamide solution in the measurement cell, and the volume average particle size obtained was defined as the rubber particle size.

<Gel content>
The gel content is the ratio of rubber-like dispersed particles in the impact-resistant vinyl aromatic resin. The impact-resistant vinyl aromatic resin having a mass of W is dissolved in toluene at a ratio of 3%, and the solution is centrifuged. The insoluble matter is separated by settling, the supernatant is removed by decantation to obtain the insoluble matter, vacuum dried at 70 ° C. for about 15 hours, cooled in a desiccator for 20 minutes, and then the mass G of the dried insoluble matter is determined. Measured and calculated by the following formula.
Gel content (amount of rubber-like dispersed particles) (mass%) = (G / W) × 100

<Swelling index>
The swelling index of impact-resistant vinyl aromatic resin is determined by dissolving impact-resistant vinyl aromatic resin in toluene, centrifuging the solution to settle insolubles, and removing the supernatant by decantation. The mass S of the insoluble matter swollen with toluene was measured, and then the insoluble matter swollen with toluene was vacuum dried at 70 ° C. for 15 hours, cooled in a desiccator for 20 minutes, and then the dry mass D of the insoluble matter was measured. , Calculated by the following formula.
Swelling degree SI = S / D

<Glossiness>
The gloss was measured in accordance with JIS Z8742 (incident angle 60 °).

<Impact resistance>
Izod impact strength was measured according to JIS K7110 (notched).

<Shock resistance retention>
Measure the Izod impact strength of a test piece for evaluation of impact resistance (with notch) prepared according to JIS K7110 after heating in a gear oven at 100 ° C. for 500 hours, and measure against the Izod impact strength before heating. The retention rate of impact resistance was calculated.

<Discoloration resistance>
Using impact-resistant vinyl aromatic resin, a flat plate (thickness 3 mm) is produced by injection molding, and the discoloration evaluation after heating for 500 hours in a gear oven at 100 ° C. is performed according to the following three criteria. did.
No color change after heating (white): ◎
Very slightly white after heating: ○
Some yellowing is observed after heating:

Example 5
8 parts by mass of the polymer 1 is dissolved in 92 parts by mass of styrene and 5 parts by mass of ethylbenzene, and further 0.15 parts by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate Stirring polymerization by adding 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane and 300 mass ppm of t-dodecyl mercaptan to styrene with respect to styrene In the tank, the polymerization was carried out by stirring in the order of 50 rpm with stirring at 102 ° C. for 5 hours, then without stirring, 120 ° C. for 1 hour, 135 ° C. for 2 hours, 150 ° C. for 2 hours, and 170 ° C. for 2 hours Continuously, heat treatment was finally performed at 230 ° C. for 30 minutes, and then unreacted styrene and ethylbenzene were removed in vacuum to obtain a styrene resin (HIPS).
This was pulverized and then pelletized with an extruder and injection molded to measure the properties and physical properties of the styrene resin. The measurement and evaluation results are shown in Table 3 below.

[Examples 6 to 9]
In the same manner as in Example 5, also for the polymers 2 to 4 and the polymer 8, styrene-based resins (HIPS) were obtained.
These were pulverized and then pelletized with an extruder and injection molded to measure the properties and physical properties of the styrene resin. Table 3 shows the measurement and evaluation results.

[Comparative Examples 6 to 10]
In the same manner as in Example 5, also for the polymers 5 to 7 and the polymers 9 to 10, styrene resins (HIPS) were obtained.
These were pulverized and then pelletized with an extruder and injection molded to measure the properties and physical properties of the styrene resin. Table 3 shows the measurement and evaluation results.

From Table 3, the polymers 1 to 4 and 8 (Examples 5 to 9) are excellent in the balance between gloss and impact resistance, and have a good impact resistance retention after 30 minutes at 250 ° C. I understood.
The polymer 5 (Comparative Example 6) that has not been partially hydrogenated and the polymer 6 (Comparative Example 7) having a selective partial hydrogenation rate of 5.2% have low impact resistance and impact resistance retention, It turned out that the discoloration is also inferior.
The polymer 7 (Comparative Example 8) in which the total hydrogenation rate after selective hydrogenation was 40% or more and the hydrogenation rate of the 1,2-vinyl bond part exceeded 99.0% was an average particle diameter of rubber particles. It became clear that gloss became inferior to 75% or less.
Moreover, it turned out that the impact resistance is inferior in the polymer 10 (comparative example 10) which is not coupled with the polymer 9 (comparative example 9) with a low coupling rate.

Example 10
10 parts by mass of ethylbenzene and 7 parts by mass of polymer 1 are dissolved in 100 parts by mass of a monomer mixture having a styrene content of 75% by mass and an acrylonitrile content of 25% by mass, and further 0.15 parts by mass of octadecyl-3- ( 1,5-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane and 200 mass ppm with respect to 100 mass parts of 3,5-di-tert-butyl-4-hydroxyphenyl) propionate and monomer mixture 1500 parts by mass of t-dodecyl mercaptan is added to 100 parts by mass of the monomer mixture, and the mixture is stirred at 300 rpm at 100 ° C. for 5 hours in a stirring tank, and then at 120 ° C. for 1 hour without stirring, 135 Polymerization is continued by successively raising the temperature at 2 ° C. for 2 hours, 150 ° C. for 2 hours and 170 ° C. for 2 hours, and finally at 230 ° C. for 30 minutes. Heat treatment is performed thereafter, unreacted styrene and vacuum removal of acrylonitrile and ethylbenzene to obtain an ABS resin.
This was pulverized and then pelletized with an extruder and injection molded to measure the properties and physical properties of the ABS resin. Table 4 shows the measurement and evaluation results.

[Example 11, Comparative Example 11]
In the same manner as in Example 10, an ABS resin was obtained for the polymer 2 and the polymer 5.
These were pulverized and then pelletized with an extruder and injection molded to measure the properties and physical properties of the ABS resin. Table 4 shows the measurement and evaluation results.

  As shown in Tables 3 and 4, it was found that Examples 10 and 11 using polymers 1 and 2 were excellent in both impact resistance retention and discoloration resistance.

  The selected part hydrogenated branched conjugated diene polymer of the present invention is used as an industrial appliance material, OA office equipment material, sports equipment material, food packaging material, medical instrument material, optical field material, etc. Has availability.

Claims (3)

A selective partially hydrogenated branched conjugated diene polymer that satisfies the following requirements (1) to (6).
(1) The branched component of the branched conjugated diene polymer that has been partially hydrogenated is 70 to 95% by mass.
(2) A molecular weight distribution curve measured by GPC of a branched conjugated diene polymer that has been partially hydrogenated, having at least two peaks and having the lowest molecular weight (unbranched component) polystyrene-reduced peak molecular weight (A) is a peak having a peak height of 50,000 to 150,000 and having a peak on the high molecular weight side (branched component) higher than the peak of the lowest molecular weight portion (component not branched). Ratio (B / A) to polystyrene-reduced molecular weight (B) is 2.5 to 3.5.
(3) The content of vinyl bonds derived from the double bond of the conjugated diene polymer of the branched conjugated diene polymer before hydrogenation of the selected part is 10 to 30%.
(4) The hydrogenation rate of the double bond of the conjugated diene polymer of the branched conjugated diene polymer which has been partially hydrogenated is 10 to 40%.
(5) The hydrogenation rate of the vinyl bond part of the branched conjugated diene polymer that has been partially hydrogenated is 80 to 99.0%.
(6) A 5% by mass styrene solution viscosity (5% SV) at 25 ° C. of the branched conjugated diene polymer partially hydrogenated is 20 to 50 centipoise (cP). A selectively partially hydrogenated branched conjugated diene polymer obtained using a homogeneous hydrogenation catalyst comprising a metallocene complex of Ti and / or Zr,
The selective partially hydrogenated branched conjugated diene polymer according to claim 1, wherein the content of Ti and / or Zr is 25 mass ppm or less. A mixture of a selectively partially hydrogenated branched conjugated diene polymer according to claim 1 or 2 and a vinyl aromatic monomer,
Or
A mixture of the branched hydrogenated branched conjugated diene polymer, a vinyl aromatic monomer, and a monomer copolymerizable with the vinyl aromatic monomer,
Having a step of radical polymerization in any one selected from the group consisting of bulk polymerization, bulk suspension polymerization, and solution polymerization,
Method for producing impact-resistant vinyl aromatic resin.