JP2000355613A - Styrene polymer and molded item prepared by molding same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrene polymer which has a syndiotactic structure, a good melt flowability, and improved moldability and melt tension while retaining its excellent mechanical strengths and resistances to heat and solvents. SOLUTION: This styrene polymer has a syndiotactic structure and satisfies the relation: [ω3000/ω30]>=25 [wherein ω3000 is the angular frequency (rad/sec) at the time when the storage modulus G' obtained by dynamic viscoelasticity measurement is 3,000 (Pa); and ω30 is the angular frequency (rad/sec) at the time when the storage modulus G' is 30 (Pa)].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrenic polymer, and more particularly to a styrenic polymer having a syndiotactic structure while maintaining excellent mechanical strength, heat resistance and solvent resistance. Has good melt fluidity,
The present invention relates to a styrene-based polymer having improved moldability and melt tension.

[0002]

2. Description of the Related Art It is already known that styrene-based polymers having a syndiotactic structure (hereinafter also referred to as SPS) have excellent mechanical strength, heat resistance and solvent resistance, and are used for various purposes. ing. However, conventional SPSs are manufactured using a catalyst called a single-site catalyst, so their molecular weight distribution is narrow and their melt tension is low. Therefore, their moldability is particularly high, such as foaming, inflation molding, and blow molding. In some cases, causing a problem in practical use.

On the other hand, Japanese Patent Application Laid-Open No. 3-119006 discloses a method for expanding the molecular weight distribution of SPS by using a catalyst in which two or more titanium compounds are mixed in order to improve moldability. However, the molecular weight distribution (Mw / Mn) of SPS shown in the examples is 10 or more, the distribution is too wide, the number average molecular weight (Mn) is as low as tens of thousands, and a large amount of low molecular weight components are contained. Therefore, there was a problem that the moldability was not improved as intended, and the strength of the molded body was also reduced.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and has excellent mechanical strength and heat resistance.
An object of the present invention is to provide a styrene-based polymer having a syndiotactic structure, which has good melt fluidity while maintaining solvent resistance, and has improved moldability and melt tension.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a styrene having a syndiotactic structure in which the degree of change in elastic modulus with respect to change in shear rate satisfies a specific relationship. Based polymer, has a good melt fluidity, excellent moldability, and found that the melt tension is improved, based on this finding,
The present invention has been completed. That is, the present invention provides the following styrene-based polymer. 1. A styrene-based polymer having a syndiotactic structure and having an angular frequency value ω ₃₀₀₀ when the storage elastic modulus G ′ obtained by measuring dynamic viscoelasticity is 3000 (Pa).
(Unit: rad / sec) and the storage elastic modulus G ′ is 30 (P
a) Value of angular frequency ω _{30 at} the time of (a) (unit: rad / se)
A styrene-based polymer in which the ratio P = [ω ₃₀₀₀ / ω ₃₀ ] of c) satisfies the relationship of the following formula (1). P = [ω ₃₀₀₀ / ω ₃₀ ] ≧ 25 (1) 2. The styrene-based polymer according to the above 1, which satisfies the following (1) and (2). (1) Mass average molecular weight (Mw) measured by GPC method
(Mw / Mn) is 5 or less (2) The ratio (Mz / Mn) of Z-average molecular weight (Mz) and (Mn) measured by GPC method is 3.5 or more. Yes 3. The styrenic polymer according to 1 or 2, which satisfies the following (1), (2) and (3) in a molecular weight distribution measured by a GPC method. (1) The ratio of the molecular weight of 50,000 or less is 1 to 30% by mass. (2) The ratio of the molecular weight of 1,000,000 or more is 1 to 30% by mass. (3) The mass average molecular weight (Mw) is 100,000 to 2,000,000. Yes 4. A molded article obtained by molding the styrene-based polymer according to any one of the above 1 to 3.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the styrenic polymer [1] of the present invention and a molded article [2] obtained by molding the polymer will be described in detail. [1] Styrene-based polymer The styrene-based polymer [1] of the present invention is a styrene-based polymer having a syndiotactic structure and has a storage elastic modulus G ′ obtained by measuring dynamic viscoelasticity of 3000 ( Pa
) ₃₀₀₀ value (unit: rad / se)
c) and the ratio P = [ω ₃₀₀₀ /] of the angular frequency value ω ₃₀ (unit: rad / sec) when the storage elastic modulus G ′ is 30 (Pa).
ω ₃₀ ] is a styrene-based polymer satisfying the relationship of the following formula (1). P = [ω ₃₀₀₀ / ω ₃₀ ] ≧ 25 (1) A styrene polymer having a syndiotactic structure is usually at least 75% by racemic diad, preferably at least 85%, or 30 by racemic pentad. %that's all,
Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (halogenated alkylstyrene), poly (alkoxystyrene), poly (vinylbenzoic acid ester) having preferably 50% or more syndiotacticity, And a mixture thereof, or a copolymer containing these as a main component. Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tert-butylstyrene), poly (phenylstyrene), and poly (vinylnaphthalene). ), Poly (vinylstyrene), and the like, and poly (halogenated styrene) includes poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like. Examples of poly (halogenated alkylstyrene) include poly (chloromethylstyrene), and examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

[0007] Of these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-tert-butylstyrene), and poly (p-methylstyrene). -Chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), hydrogenated polystyrene, and copolymers of these structural units.

Next, P in the above formula (1) is a storage elastic modulus G ′ obtained by measuring dynamic viscoelasticity described below.
Is 3000 (Pa), the angular frequency value ω ₃₀₀₀ (unit: rad / sec), and the storage elastic modulus G ′ is 30 (Pa).
Is the ratio [ω ₃₀₀₀ / ω ₃₀ ] of the angular frequency value ω ₃₀ (unit: rad / sec) at the time of <Measurement of dynamic viscoelasticity> The dynamic viscoelasticity was measured using a ARES manufactured by Rheometric Scientific F. Co., Ltd., and a 1 mm thick sample sheet obtained by molding with a press molding machine was inserted between a cone and a disk. And the temperature is raised to 300 ° C., the strain is set to 20%, and the angular frequency ω (rad / sec)
Is changed. By reading ω ₃₀₀₀ and ω ₃₀ from the curve representing the relationship between ω and G ′ obtained by measurement, P
Ask for. If the measurement cannot be performed in the measurement range at 300 ° C., the measurement may be performed at another temperature and a master curve at 300 ° C. may be created according to the temperature-time conversion rule.

P indicates the degree of change in the elastic modulus with respect to the change in the shear rate. The larger the value of P, the smaller the change in the elastic modulus with respect to the change in the shear rate. P in the styrenic polymer of the present invention retains good melt fluidity,
In addition, the moldability and the melt tension need to be 25 or more in order to be excellent. Preferably it is 30 or more, more preferably 35 or more. If P is less than 25, the change in the elastic modulus is large and the moldability is reduced.

Further, the styrenic polymer of the present invention preferably satisfies the following requirements (1) and / or (2) in addition to the above requirements. (1) Mass average molecular weight (Mw) measured by GPC method
And the ratio (Mw / Mn) of the number average molecular weight (Mn) to 5 or less,
Preferably 2.3 to 4.5, more preferably 2.5 to
(2) The ratio (Mz / Mn) of the Z-average molecular weight (Mz) to (Mn) measured by the GPC method is 3.5 or more, preferably 5.0 or more, more preferably 6.0. In this case as described above, the balance between the effect of improving the moldability and the mechanical properties of the molded product is excellent, which is preferable.

When Mw / Mn exceeds 5, the composition contains a large amount of low molecular weight components, which may lower the strength of the molded product. Further, when Mz / Mn is less than 3.5, the effect of improving the melt tension is small, and the moldability may not be improved.

Further, the styrenic polymer of the present invention more preferably satisfies the following requirements (1), (2) and (3) in the molecular weight distribution measured by the GPC method in addition to the above requirements. (1) Molecular weight 50,000 or less the ratio (hereinafter, C ₅₀ referred to as) 1 to 30 wt%, more preferably from 4 to 20 wt% (2) having a molecular weight of 1,000,000 or more ratio (hereinafter, also referred to as C ₁₀₀₀ ) Is from 1 to 30% by mass, more preferably from 4 to 25% by mass, particularly preferably from 6 to 20% by mass. (3) The mass average molecular weight (Mw) is from 100,000 to 2,000,000, more preferably from 150,000 to 80,000. When the above relationship is satisfied, the low molecular weight component is small and the high molecular weight component is relatively large, so that the melt tension is improved and the moldability is improved. Furthermore, the mechanical strength is improved.

If the ratio of the molecular weight of 50,000 or less is less than 1% by mass, the fluidity may decrease. On the other hand, if it exceeds 30% by mass, the melt tension may decrease. In addition, molecular weight 10
If the proportion of the component of 0000 or more is less than 1% by mass, the melt tension may decrease. On the other hand, if it exceeds 30% by mass, the fluidity may decrease. When Mw is less than 100,000, the mechanical strength of the molded body cannot be obtained, and when it exceeds 1,000,000, the viscosity of the resin increases, which may cause a decrease in fluidity.

Further, as the styrenic polymer of the present invention,
Is the ratio of the molecular weight of 50,000 or less (C ₅₀) And the mass average
The molecular weight (Mw) is log (C₅₀) ≧ −1.48 × log (Mw / 100
More preferably, the relationship of 0) +4.44 is satisfied.

The GPC was measured using a GPC manufactured by Tosoh Corporation.
145 ° C. using a column (GMHHR-H (S) HT) and 1,2,4-trichlorobenzene as an eluent
It was measured in.

The styrene polymer of the present invention more preferably satisfies the following (1) in addition to the above requirements. (1) 2 grams of dry polymer is added to 12 milliliters of 1,
When dissolved in 2,4-trichlorobenzene at 170 ° C., there should be no components insoluble in the solvent. When (1) is satisfied, the melt tension is improved and the melt tension (M
T) and the melt index (MI) satisfy the relationship of the following equation (2). log (MT) ≧ −0.887 × log (MI) +0.654 (2) By satisfying the expression (2), the fluidity at the time of melting is better and the melt tension is higher than the conventional SPS. It shows that.

The above MT and MI are measured by the following methods. <Measurement method of MI> MI (g / 10 min) was measured according to JIS-
In accordance with K7210, the measurement was performed at a load of 11.76 N and a measurement temperature of 300 ° C. <Measurement method of MT> Using Toyo Seiki Capillograph,
Measurement temperature 290 ° C, die shape 40L × 2.095Φ (m
m), MT (unit: g) is measured at an extrusion speed of 10 mm / min and a take-up speed of 16.0 m / min. The MT obtained under these conditions is defined as MT ₁₀₀ (g). However, MT
_{If 100} cannot be measured, reduce the take-off speed sequentially, and
Is measured.

In the general formula (2), MT
_{Although 100} (g) is usually used, MT obtained by lowering the take-off speed may be used. Next, a method for obtaining the styrenic polymer of the present invention will be described.

As a method for obtaining the styrenic polymer of the present invention, for example, a method of blending two or more kinds of SPS having different molecular weights can be mentioned. Specifically, low molecular weight SPS
And a method of blending a high molecular weight SPS into the mixture. As the styrene-based polymer of the present invention, the ratio of the respective SPS mass average molecular weights (Mw), that is, the low molecular weight SPS
Those weight average molecular weight Mw _LM and a high molecular weight of the ratio of the weight average molecular weight Mw _HM of the SPS (Mw _HM / Mw _LM) is obtained by blending two or more SPS satisfies the relationship Mw _HM / Mw _LM ≧ 3 It is preferred that If the ratio is less than 3, the effect of improving the melt tension may be small.

Also, the molecular weight distribution of low molecular weight SPS (M
w / Mn) and the molecular weight distribution (Mw /
Mn) is preferably 1.5 to 2.5. Further, the Mw _LM is preferably 100,000 or more,
More preferably, it is 140,000 or more. When the Mw _LM is less than 100,000, the low molecular weight component increases, and the mechanical strength of the obtained molded product may decrease.

The method of mixing two or more kinds of SPS having different molecular weights is not particularly limited, and examples thereof include a method of dissolving in a solvent and mixing, and a method of kneading with an extruder. Examples of a method for producing the SPS of each component include a method of polymerizing an aromatic vinyl monomer in the presence of a catalyst comprising a transition metal compound and an organoaluminum compound. A known method may be used as a method for producing such a styrene-based polymer having a syndiotactic structure. For example, in an inert hydrocarbon solvent or in the absence of a solvent, a styrene-based monomer (in the presence of a titanium compound as a transition metal compound and a catalyst comprising a condensation product of water and a trialkylaluminum as an organoaluminum compound) A method of polymerizing the above-mentioned styrene-based polymer (a monomer corresponding to the styrene-based polymer) (JP-A-62-187708). Similarly, poly (halogenated alkylstyrene) and hydrogenated polymers thereof are similarly known in the art, for example, JP-A-1-46912, JP-A-1
It can be produced by the method described in JP-B-178505.

As the aromatic vinyl monomer used here, styrene, methylstyrene, ethylstyrene,
Isopropyl styrene, tertiary butyl styrene,
Substituted styrenes such as phenylstyrene, vinylstyrene, vinylnaphthalene, chlorostyrene, bromostyrene, fluorostyrene, chloromethylstyrene, methoxystyrene, ethoxystyrene, and butoxystyrene may be mentioned, and these may be used alone or copolymerized.

If necessary, a comonomer other than the aromatic vinyl monomer may be contained. Examples thereof include olefin monomers such as ethylene, propylene, butene, hexene, and octene; diene monomers such as butadiene and isoprene; cyclic olefin monomers; cyclic diene monomers; and polar vinyl monomers. [2] Molded article The molded article of the present invention is a molded article obtained by molding the styrene-based polymer [1]. The molded article of the present invention, for example,
The neck-in amount defined by “die width−formed sheet width” at the time of casting a cast sheet is small, and sheet formability is excellent.

The shape of the molded article of the present invention is not particularly limited, and may be a sheet, a film, a container, an injection molded article, a blow molded article, a foam molded article, or the like. In particular, the styrene-based polymer of the present invention is preferably used for forming a film, a stretched film, and a foamed sheet.

The molding method is not particularly limited as long as it is a method for molding the styrenic polymer of the present invention or, if necessary, a composition to which an antioxidant, an inorganic filler, and an organic filler are added. Absent. Examples of the molding method include an extrusion molding method, a T-die molding method and an inflation molding method for forming a film or a sheet, and an injection molding method for another structure such as a container. here,
The extruder may be either a single screw extruder or a twin screw extruder, and may or may not have a vent. Extrusion conditions are not particularly limited and may be appropriately selected. Preferably, the temperature at the time of melting is selected in a range of from the melting point of the molding material to 50 ° C. higher than the decomposition temperature, and the shear stress is preferably set to 50 N / cm ² or less. . After the extrusion molding, it is desirable to cool and solidify the molded body. At this time, various refrigerants such as gas, liquid, and metal can be used. In the case where a metal roll is used for forming the sheet, a method such as an air knife, an air chamber, a touch roll, or an electrostatic application may be used.
The temperature of solidification by cooling is 0 ° C. to 30% of the glass transition temperature of the material.
° C higher temperature range, preferably 70 ° C above the glass transition temperature.
The temperature is in the range of not less than 0 ° C and not more than glass transition temperature. The cooling rate is not particularly limited, and may be appropriately selected within the range of 200 to 3 ° C./sec, preferably 200 to 10 ° C./sec. The extruder may be provided with a suitable filter.

The molded article of the present invention has a glass transition temperature of from 20 to
The heat treatment can be performed at a temperature of 0 ° C, preferably 140 to 180 ° C, more preferably 150 to 170 ° C. When the sheet is stretch-formed, the sheet may be stretched simultaneously in the vertical and horizontal directions, or may be sequentially stretched in an arbitrary order. The stretching may be performed in a single stage or in multiple stages. The stretching ratio is arbitrary, and the area ratio is 2 times or more, preferably 3 times or more. As the stretching method, various methods such as a method using a tenter, a method of stretching between rolls, a method of bubbling by gas pressure, and a method of rolling can be used. The stretching temperature may be set between the glass transition temperature and the melting point of the material. Stretching speed is 1 × 10 to 1 × 1
What is necessary is just to set between ^0.5 % / min. It is also possible to heat set the stretched molded article at a temperature between the glass transition temperature and the melting point.

When the styrenic polymer of the present invention is used, the mechanical strength of a molded article can be improved. A foam can also be obtained by mixing with various foaming agents and foaming by heating. As a method for obtaining the foam, a known technique is used. For example, the methods exemplified in JP-A-8-120110 and JP-A-2-248438 are exemplified. By using the styrene polymer of the present invention, a foam having a high closed cell ratio can be obtained even at a high expansion ratio.

As described above, the molded article of the present invention is obtained by molding the above-mentioned styrene-based polymer. However, the molded article of the present invention impairs the object of the present invention by the styrene-based polymer. In the range not to be used, generally used thermoplastic resin, rubber-like elastic material, antioxidant, inorganic filler, nucleating agent,
It may be obtained by molding a composition obtained by adding a crosslinking agent, a crosslinking assistant, a plasticizer, a compatibilizer, a coloring agent, an antistatic agent and the like.

As the thermoplastic resin to be added, atactic polystyrene, isotactic polystyrene,
Styrene polymers such as AS resin and ABS resin, PET
Polyester, PC, polyphenylene oxide (PPO), polysulfone, polyether such as polyethersulfone, polyamide, PPS, polyoxymethylene and other condensation polymers, polyacrylic acid, polyacrylate, polymethyl methacrylate, etc. Examples include acrylic polymers, polyolefins such as polyethylene, polypropylene, and polybutene; halogen-containing vinyl compound polymers such as polyvinyl chloride and polyvinylidene chloride; and mixtures thereof.

Among them, an elastomer (rubber) having rubber elasticity at room temperature is preferable. For example, hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-
Styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS),
Rubber containing a styrene compound such as hydrogenated styrene-isoprene-styrene block copolymer (SEPS), styrene-butadiene random copolymer (SBR), ABS rubber, natural rubber, polybutadiene, polyisoprene;
Polyisobutylene, neoprene (registered trademark), acrylic rubber, urethane rubber, silicone rubber, polyetherester rubber, polyesterester rubber, olefin-based rubber (elastomer), specifically ethylene-propylene copolymer rubber, ethylene-propylene- Ethylene such as diene copolymer rubber, ethylene-butene copolymer rubber, ethylene-hexene copolymer rubber, ethylene-octene copolymer rubber, ethylene-styrene copolymer rubber, α-olefin, aromatic vinyl, diene, etc. And a mixture thereof.

Further, rubber obtained by modifying the above rubber with a modifier having a polar group can also be used. Examples include maleic anhydride-modified rubber, epoxy-modified rubber, and the like.

There are various antioxidants,
In particular, a phosphorus-based antioxidant such as tris (2,4-di-t-butylphenyl) phosphite, a monophosphite such as tris (mono- and di-nonylphenyl) phosphite and a diphosphite, and a phenol-based antioxidant are preferable. . Other examples include amine antioxidants and sulfur antioxidants. These can be used alone or as a mixture. The addition amount may be 0.0001 to 1 part by mass based on 100 parts by mass of the styrene-based polymer.

Further, the inorganic filler may be any of fibrous, granular and powdery materials, and specifically, talc, mica,
Examples thereof include carbon black, titanium dioxide, silica, calcium carbonate, alumina, and metal powder. .

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

The resin characteristics were measured by the method described in the text. [Preparation Example 1] Preparation of catalyst In a vessel sufficiently dried and purged with nitrogen, toluene, 3.8 mmol of triisobutylaluminum, 16.8 mmol of methylaluminoxane and 0.15 mmol of octahydrofluorenyltitanium trimethoxide were placed, and the Ti concentration was changed. To 3 mmol / l. Each component was stirred for 1 hour after mixing, and used as a catalyst. [Preparation Example 2] Preparation of catalyst In a container sufficiently dried and purged with nitrogen, toluene, 3.8 mmol of triisobutylaluminum, 11.3 mmol of methylaluminoxane, and 0.15 mmol of pentamethylcyclopentadienyltitanium trimethoxide were added.
It was prepared to have an i concentration of 3 mmol / l. Each component was stirred for 1 hour after mixing, and used as a catalyst. [Production Example 3] Production of SPS 5 liters of styrene and triethylaluminum were put into a sufficiently dried and purged reactor so that the molar ratio of styrene / triethylaluminum was 3500/1.
Stir well. After heating the mixture of styrene and triethylaluminum to 85 ° C., 21 ml of the catalyst prepared in Production Example 1 was added to initiate polymerization. One hour later, methanol was added to terminate the polymerization. The obtained polymer was washed with methanol and dried at 200 ° C. for 2 hours. Yield 1
130 g. The weight average molecular weight was 153,000. [Production Example 4] Production of SPS The same procedure was carried out as in Production Example 3, except that instead of 5 liters of styrene, 4.4 liters of styrene and 0.6 liters of paramethylstyrene were used, and the weight average molecular weight was 16.3.
1170 g of a polymer were obtained. [Production Example 5] Production of SPS The same procedure as in Production Example 4 was carried out except that the polymerization temperature was changed to 78 ° C, to obtain 1210 g of a polymer having a mass average molecular weight of 212,000. [Production Example 6] Production of SPS The same procedure as in Production Example 3 was carried out except that the polymerization temperature was changed to 80 ° C, and polymerization was carried out without adding triethylaluminum, to obtain 1120 g of a polymer having a weight average molecular weight of 304,000. . [Production Example 7] Production of SPS Performed in the same manner as in Production Example 4 except that the polymerization temperature was changed to 63 ° C and polymerization was performed without adding triethylaluminum.
1250 g of a polymer having a weight average molecular weight of 611,000 was obtained. [Production Example 8] Production of SPS 4.4 liters of styrene and 0.6 liter of paramethylstyrene were charged into a reactor which had been sufficiently dried and purged with nitrogen, and further, styrene / triethylaluminum = 7000/1 in a molar ratio of triethylaluminum. So that
Stirred enough. After heating up to 70 ° C., Production Example 2
42 ml of the catalyst prepared in 1) was added to initiate polymerization. One hour later, methanol was added to terminate the polymerization. The obtained polymer was washed with methanol and dried at 200 ° C. for 2 hours. The yield was 1230 g. The weight average molecular weight is 10
It was 30,000. [Production Example 9] Production of SPS Except that the polymerization temperature was changed to 50 ° C, and polymerization was carried out without adding triethylaluminum, the same procedure was carried out as in Production Example 8, to obtain 1105 g of a polymer having a weight average molecular weight of 2.5 million. [Production Example 10] Production of SPS Production Example 9 was carried out in the same manner as in Production Example 9 except that 4.4 liters of styrene and 0.6 liter of paramethylstyrene were used instead of 5 liters of styrene.
1100 g of 530,000 polymers were obtained.

As described above, in the polymers obtained in Production Examples 3 to 10, the molecular weight distribution (Mw / Mn) of the low molecular weight SPS (Production Examples 3 to 6) and the high molecular weight SPS (Production Examples 7-1)
Table 1 shows the molecular weight distribution (Mw / Mn) of (0).

[0037]

[Table 1]

Example 1 A total of 1200 (g) and 13 liters of para-xylene were charged into a 20-liter container so that the polymers of Production Examples 5 and 8 were in a weight ratio of 80:20. The mixture was stirred at 1 ° C. for 1 hour to dissolve. The obtained solution was cooled, gelled and pulverized, washed with methanol, and dried at 200 ° C. for 2 hours to obtain a polymer blend powder. This powder was pelletized at 300 ° C. with a Labo Plastomill single screw extruder manufactured by Toyo Seiki Co., Ltd.
The resin properties of the pellets were measured. The results obtained are shown in Tables 2 and 3. Example 2 The polymer of Production Example 5 was changed to Production Example 4, and the polymer of Production Example 4 was further modified.
Example 8 was carried out in the same manner as in Example 1, except that the mass ratio of the polymer of Production Example 8 was changed to 65:35. The obtained result is
The results are shown in Tables and Table 3. Example 3 The polymers of Production Example 4 and Production Example 9 were mixed in a mass ratio of 70:30,
After powder dry blending to a total of 1000 (g), the mixture was pelletized at 300 ° C. using a Labo Plastomill twin screw extruder manufactured by Toyo Seiki Co., Ltd. About this pellet,
The resin properties described above were measured. The results obtained are shown in Tables 2 and 3. Example 4 The same procedure as in Example 3 was carried out except that the polymers of Production Examples 3 and 10 were used in a mass ratio of 85:15. The results obtained are shown in Tables 2 and 3. Comparative Example 1 The polymer of Production Example 6 was pelletized using a Plastomill single screw extruder manufactured by Toyo Seiki. The resin properties of the pellets were measured. The obtained result is
The results are shown in Tables and Table 3. Comparative Example 2 The polymer of Production Example 5 was pelletized using a Plastomill single screw extruder manufactured by Toyo Seiki. The resin properties of the pellets were measured. The obtained result is
The results are shown in Tables and Table 3. [Comparative Example 3] The same operation as in Example 1 was carried out except that the polymers of Production Examples 5 and 7 were used in a mass ratio of 90:10.
The results obtained are shown in Tables 2 and 3. Example 5 Cast Sheet Molding Using the polymer of Example 2, cast sheet molding was performed under the following molding conditions, and the neck-in amount defined by “die width−molded sheet width” was measured. The smaller the value, the better the sheet formability. The average width of the sheet obtained by molding was 67 mm, and the neck-in amount was 8 mm.
3 mm.・ Molding machine: 20 mmφ single screw extruder Set temperature = 300 ° C. ・ Die: 150 mm width, lip opening = 1 mm ・ Discharge: 6 kg / hr ・ Roll speed: 10 m / min [Comparative Example 4] Cast sheet molding Comparative Example 1 The procedure was performed in the same manner as in Example 5 except that the polymer was changed to.

The average width of the sheet obtained by molding is 4
2 mm, and the neck-in amount was 108 mm.

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

According to the SPS of the present invention, a molded article excellent in workability such as foam molding, blow molding and inflation molding, and excellent in mechanical strength and solvent resistance can be obtained. Further, it is suitable for the production of foam materials such as sheets and films for food packaging materials, containers, building materials, automobile parts, and food containers.

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Claims (4)

[Claims] 1. A styrene polymer having a syndiotactic structure, wherein an angular frequency value ω ₃₀₀₀ when the storage elastic modulus G ′ obtained by measuring dynamic viscoelasticity is 3000 (Pa) (unit: rad / sec) and the value of the angular frequency ω ₃₀ when the storage elastic modulus G ′ is 30 (Pa) (unit: rad)
/ Sec) ratio P = [ω ₃₀₀₀ / ω ₃₀ ] is a styrene-based polymer satisfying the following formula (1). P = [ω ₃₀₀₀ / ω ₃₀ ] ≧ 25 (1) 2. The method according to claim 1, wherein the following conditions (1) and (2) are satisfied.
The styrene polymer according to the above. (1) Mass average molecular weight (Mw) measured by GPC method
(Mw / Mn) is 5 or less (2) The ratio (Mz / Mn) of Z-average molecular weight (Mz) and (Mn) measured by GPC method is 3.5 or more. is there 3. The molecular weight distribution measured by the GPC method, wherein the following (1), (2) and (3) are satisfied.
Or the styrenic polymer according to 2. (1) The ratio of the molecular weight of 50,000 or less is 1 to 30% by mass. (2) The ratio of the molecular weight of 1,000,000 or more is 1 to 30% by mass. (3) The mass average molecular weight (Mw) is 100,000 to 2,000,000. is there 4. A molded article obtained by molding the styrenic polymer according to claim 1.