JPH04255706A - Rubber-modified styrene-based resin excellent in strength - Google Patents

Abstract

PURPOSE:To provide the subject resin containing a rubber composed of an aromatic vinyl polymer and a conjugated diene polymer, containing a continuous phase having a styrene-base unit, an acrylic ester-based unit and a long chain alkyl group-containing unit, capable of low temperature molding and capable of heightening the molding cycle. CONSTITUTION:A rubbery elastic material composed of an aromatic vinyl hydrocarbon polymer block and a conjugated diene-based block in a weight ratio of (20:80)-(50:50) is blended with styrene, an acrylic-ester, an ethylbenzene, etc., and the resultant mixture is polymerized to obtain the objective rubber-modified styrene-based resin containing a continuous phase composed of respective constituting units of (A) formula I (R1 is H or methyl; R2 is H or 1-5C alkyl), (B) formula II (R3 is H or methyl; R4 is 1-8C alkyl) and (C) formula III (l and n are integer of 1-20; m is 0 or integer of 1-5; R5 to R8 are H, 1-5C alkyl, phenyl, etc.) in a ratio satisfying the component (A)=80-99.5wt.%, the component (B)=0.5-20wt.% and the component (C)/[the component (A) + the component (B)]=0.01-0.00001 and dispersed particles composed of the above-mentioned rubbery elastic material and having 0.1-1.2mum particle size.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new styrenic resin. More specifically, the present invention provides styrene comprising a styrene structural unit, an acrylic ester (methacrylic ester) structural unit, and a structural unit having a long alkyl chain represented by a specific structural formula in a specific proportion. The present invention relates to a styrenic resin with excellent strength, which has a continuous phase of a polymer and a dispersed phase of a rubber-like elastic body consisting of a vinyl aromatic hydrocarbon polymer block and a polymer block mainly composed of a conjugated diene.

0002

[Prior Art and Problems to be Solved by the Invention] Styrenic resins are widely used as molding materials for household goods, electrical products, packaging, etc. because they have excellent transparency, moldability, and rigidity. Ta. As the fields of use have expanded, there has been a strong demand for improved strength of styrene resins. In response to this demand, methods such as increasing the molecular weight or optimizing the molecular weight distribution have been attempted, but these efforts have not yet satisfied the market demand. In order to improve the strength of styrenic resins, it is necessary to use styrenic polymers containing rubber-like elastic bodies as dispersed particles, that is, rubber-reinforced styrenic resins (H
IPS), but this resin is opaque even when formed into a sheet or film, so it cannot be used in fields that require transparency. Recently, attempts have been made to improve transparency by reducing the size of dispersed particles of rubber-like elastic bodies, but although some improvement has been observed, the level is not satisfactory.

[0003] On the other hand, styrenic resins made by blending polystyrene and styrene-butadiene block copolymers are currently widely used in the market because they fairly satisfy the market requirements. However, this styrene resin requires a large amount of styrene-butadiene block copolymer in order to provide strength, leading to an increase in the cost of the resin. Furthermore, since the styrene-butadiene block copolymer is a non-crosslinked material, it has the disadvantage that its strength has a very large directional dependence on orientation during molding. Further, in the field of sheets and films, since rework is used, the styrene-butadiene block copolymer is crosslinked, producing a so-called gel-like substance, which significantly deteriorates the surface properties of the sheets and films.

In the field of sheets and films, there is a demand for resins that can be molded at low temperatures in order to improve productivity and deep drawability. Furthermore, due to recent environmental issues, there is a demand for resins that can replace vinyl chloride resins. The above polystyrene and styrene-butadiene block copolymer blend resins do not yet satisfy this requirement. Although various improvements have been made to blend resins of polystyrene and styrene-block copolymers, no one has yet been developed that completely satisfies market demands. In order to overcome this limit, we introduced a second monomer that is copolymerizable with the styrenic monomer.
It is known to lower heat resistance. It is expected that market demands can be met by blending this resin with a rubber-like elastic material, such as a tyrene-butadiene block copolymer, but in reality, it is a blend of polystyrene and a rubber-like elastic material. Less strong and impractical.

JP-A-2-103207 describes the copolymerization of styrene with butyl acrylate, butyl methacrylate, or a mixture of butyl acrylate and 2-ethylhexyl methacrylate using a polyfunctional initiator. However, the ratio of styrene monomer/acrylic ester (methacrylic ester) monomer is 70/30 to 40/60 (g/g), which is a small amount of styrene monomer, and the polymerization method is suspension polymerization. The obtained styrenic resin is opaque due to the low polymerization temperature of 75°C to 105°C, and it remains opaque even when blended with a rubber-like elastic material, so transparency is required. It cannot be used for any purpose. As described above, a resin that satisfies the balance of strength, moldability, and transparency required by the market has not yet been developed.

[0006]

[Means for Solving the Problems] In view of the current situation, the present inventors have made extensive studies and have developed an acrylic ester (methacrylic ester) as a second monomer copolymerizable with a styrene monomer. ) and a specific amount of long alkyl chains introduced using an appropriate method as a continuous phase, consisting of a vinyl aromatic hydrocarbon polymer block and a polymer block mainly composed of a conjugated diene. By optimizing the particle size of the rubber-like elastic material in the dispersed phase of a styrene-based resin, a new styrenic resin with an excellent balance of transparency, moldability, and strength has been created. By molding this styrene resin, sheets, films, and sheets with excellent transparency, strength, and moldability can be obtained.
They discovered that a molded article with excellent transparency and strength could be obtained, and completed the present invention.

That is, the present invention has a polymer block mainly composed of a vinyl aromatic hydrocarbon polymer block and a conjugated diene, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene is 20:80 to 50. :50 in a rubber-modified styrenic resin containing a rubber-like elastic body as dispersed particles, in which the continuous phase is (A)

(B): (In the formula, R1 is hydrogen or a methyl group, and R2 is hydrogen or an alkyl group having 1 to 5 carbon atoms.) (B): (In the formula, R3 is hydrogen or a methyl group, R4 is an alkyl group having 1 to 8 carbon atoms.However, when R3 is a methyl group, R4 is an alkyl group having 2 to 8 carbon atoms.)(C): (In the formula, l and n are 1 ~20 integer, m is 0 or 1 to 5
is an integer. R5, R6, R7, and R8 are each hydrogen, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group. ) Consisting of the structural units shown in (A), (B)
The ratio of (A): 80 to 99.5% by weight (B):
0.5 to 20% by weight [however, (A) + (B) = 100% by weight], and the structural unit ratio (C) / [(A) + (B)] = 0.01 to 0.0
0001, and the dispersed particle size of the dispersed phase is 0.1 to 0.0001.
The present invention provides an excellent rubber-modified styrenic resin having a particle diameter of 1.2 μm and a rubber-like elastic material content of 1 to 20% by weight.

The present invention will be explained in detail below. The amount of structural unit (B) forming the continuous phase ranges from 0.5 to 20% by weight. More preferably, it is in the range of 2 to 17% by weight. If it exceeds 20% by weight, the heat resistance becomes low, and as a result, the practical range of sheets, films, and molded products becomes extremely narrow, which is not preferable. If the amount is less than 0.5% by weight, the heat resistance of the styrene resin will increase, so the effect of shortening the molding cycle and improving deep drawability will be small, and sheets, films, and molded products with excellent strength will be obtained. I can't do it.

The structural unit ratio (C)/[(A)+(B)] is in the range of 0.01 to 0.00001. More preferably, it is in the range of 0.005 to 0.00005. 0.01
If it exceeds this value, the effect of improving the strength will be reduced, and the cost of the styrene resin and the styrenic resin sheet, film, and molded article made from it will increase, which is undesirable. When it is less than 0.00001, the effect of improving strength is not exhibited, and a styrene resin, styrenic resin sheet, film, or molded article with excellent strength cannot be obtained.

[0010] The degree of polymerization of the continuous phase of the styrenic resin of the present invention is not particularly limited;
The viscosity of a 10% by weight toluene solution at 25° C. can be set in the range of 15 centipoise to 80 centipoise, more preferably in the range of 20 centipoise to 70 centipoise.

The total amount of the styrene monomer, acrylic acid (methacrylic acid) ester monomer, and polymerization solvent in the styrenic resin of the present invention is 0.15% by weight, more preferably 0.1% by weight.
% by weight or less. If it exceeds 0.15% by weight, it is unfavorable in terms of food hygiene. In addition, the total amount of dimers and trimers of styrene monomers, acrylic acid (methacrylic acid) ester monomers, styrene monomers, acrylic acid (methacrylic acid) ester monomers, and polymerization solvent is 0.8% by weight or less, preferably 0.7% by weight or less, more preferably 0.8% by weight or less.
It is 6% by weight or less. If the total amount of styrene-based low molecular weight compounds exceeds 0.8% by weight, it is not preferable because the appearance of the sheet, film, or molded product will be poor due to mold suet during extrusion or molding of the sheet or film, and the strength will also decrease. .

In the present invention, the structural unit (A) includes, for example, those having the following structure.

[Case 2]

In the present invention, the structural unit (B) includes, for example, those having the following structure. In the present invention, examples of the structural unit (C) include those having the following structure.

[0014]

[0015]

[Chemical formula 3]

Alternatively, it may have two or more structural units of the above structural formula randomly. As the dispersed phase of the present invention,
Consisting of a rubbery elastic body that has a polymer block mainly composed of a vinyl aromatic hydrocarbon polymer block and a conjugated diene, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene is 20:80 to 50:50. It is a particle. In a rubber-like elastic body in which vinyl aromatic hydrocarbons and conjugated dienes are randomly bonded, the transparency of the styrenic resin is poor, and in order to reduce the particle size, excessive shearing occurs during phase transformation of the rubber-like elastic body. It is necessary to apply stress, making it unsuitable for practical production.

The number and combination of vinyl aromatic hydrocarbon polymer blocks and conjugated diene-based polymer blocks forming the rubber-like elastic body of the present invention are not particularly limited. Here, the polymer block mainly composed of conjugated diene is a polymer block in which the content of conjugated diene is 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. The vinyl aromatic hydrocarbon copolymerized in the polymer block mainly composed of conjugated diene may be uniformly distributed in the polymer block or may be distributed in a tapered shape.

The weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene in the rubber-like elastic body is from 20:80 to 50:50. When the weight ratio of vinyl aromatic hydrocarbon is less than 20, transparency deteriorates, which is not preferable. Moreover, when it exceeds 50, the strength decreases, which is not preferable. The weight of the vinyl aromatic hydrocarbon polymer block in the rubbery elastomer can be determined by a method of oxidizing the copolymer with di-t-butyl hydroperoxide using osmium tetroxide as a catalyst [for example, L. M. K
OLTHOFF, et al. , J. Polym. S
ci. 1429 (1946)].

The rubber-like elastic body used in the present invention can basically be manufactured by conventionally known methods, for example, Japanese Patent Publication No. 36-1
Examples include methods described in Japanese Patent Publication No. 9286, Japanese Patent Publication No. 43-14979, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 48-4106, and Japanese Patent Publication No. 49-36957. In the present invention, styrene, o-methylstyrene, p-methylstyrene, pt-butylstyrene, α-styrene, etc. can be used as the vinyl aromatic hydrocarbon. These may be used alone or in combination of two or more. A particularly common example is styrene. Further, the conjugated diene is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene,
2-methyl-1,3-butadiene (isoprene), 2,
3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. can be used. These may be used alone or in combination of two or more. Particularly common ones include 1,3-butadiene and isoprene.

[0020] The particle size of the dispersed phase of the present invention is 0.1 to 1.2.
It is necessary to be in the μm range. More preferably 0
．． It is necessary that it is 2 to 0.9 μm. When the dispersed particles are less than 0.1 μm, no strength reinforcing effect is exhibited. Or the effect is very small. On the other hand, the dispersed particle size is 1.2
If it exceeds μm, the strength reinforcing effect is great, but the transparency deteriorates, which is not preferable. The particle size referred to in the present invention means a number average particle size unless otherwise specified. There are no particular restrictions on the particle size distribution, but the following two types are preferred. One has a particle size distribution (weight average particle size/number average particle size) of 3.0.
The distribution states are as follows, and the others are distribution states with a twin-mountain distribution. At this time, the distribution of large and small particle diameters is 2.0 or less, and the particle diameter is 0.1 to 1.0, which is a constituent requirement of the present invention.
It is necessary that the thickness be within the range of 2 μm.

The amount of rubbery elastomer in the rubber-modified styrenic resin of the present invention is 1 to 20% by weight. Preferably 1~
It is 15% by weight. When the amount of the rubber-like elastic body is less than 1% by weight, no strength reinforcing effect is exhibited. Moreover, if it exceeds 20% by weight, the transparency decreases and the usage is greatly limited, which is not preferable.

In order to obtain the styrenic resin of the present invention, it is first necessary to carry out the first stage polymerization step in the presence of a polymerization initiator consisting of a specific low-temperature decomposition type organic peroxide. This low temperature decomposition type organic peroxide has the general formula: (wherein l and n are integers of 1 to 20, m is 0 or 1 to 5
R1, R2, R3, R4 are each hydrogen, or an alkyl group of 1 to 5, a cyclohexyl group, or a phenyl group. ) It has at least 3 repeating units, preferably 5 to 30 repeating units. Examples of such organic peroxides include those having the following repeating units.

[0023]

[0024]

[C4]

[0025] A low-temperature decomposition type organic peroxide in which two or more structural units having the above structure are randomly bonded can also be used. Further, in the present invention, organic peroxides having these repeating units can be used alone or in combination of two or more. These organic peroxides are disclosed in Japanese Patent Publication No. 63-32089, Japanese Patent Application Laid-open No. 59-93725, and Japanese Patent Application Laid-open No. 59-17.
It can be synthesized according to the method described in Japanese Patent No. 6320. The mixing ratio of styrene monomer and acrylic ester (methacrylic ester) monomer is 100/0 to 80/
0.005 to 2.0 parts by weight of the above-mentioned low-temperature decomposition type organic peroxide is added per 100 parts by weight of the monomer, which is 20 (% by weight), and polymerized at a temperature of 110° C. or lower. 15% by weight or more of the continuous phase of the styrenic resin finally obtained at this stage,
It is necessary to obtain preferably 20% by weight or more of the styrenic polymer.

[0026] After this, the polymerization is further continued, or
It is mixed with a copolymerization solution of styrenic monomer-acrylic acid ester (methacrylic acid ester) monomer polymerized in a separate reactor, and the target composition ratio and degree of polymerization of the continuous phase of styrenic resin are determined. A styrenic monomer and/or an acrylic acid ester (methacrylic acid ester) monomer is added as necessary so as to obtain the desired result, and polymerization is carried out at an optimum polymerization temperature. The dispersed phase is formed by a method conventionally used in the production of rubber-reinforced polystyrene. That is, a rubbery elastic material is dissolved in a mixed solution of styrene monomer and acrylic acid ester (methacrylic acid ester) monomer, polymerization is performed in a reactor equipped with a stirrer, phase conversion of the rubbery elastic material is performed, and dispersion is performed. form particles. The particle size of the dispersed particles is controlled by shear stress caused by stirring.

[0027] Phase transformation of the rubber-like elastomer can occur during the polymerization of a monomer mixed solution containing a low-temperature decomposition type organic peroxide, in a separate reactor, or after the two polymerization solutions are mixed. can be done. The method and location of phase conversion are not particularly limited. The content of rubber-like elastic material can be achieved by adjusting the raw materials and polymerization rate to reach the target content, but it is possible to achieve the content of rubber-like elastic material by adjusting the raw materials and polymerization rate to reach the target content. This can also be achieved by mixing it with a separately manufactured styrenic resin that does not contain a rubber-like elastic body. However, it is a matter of course that all the constituent requirements of the present invention are satisfied. At this time, it is also possible to use a polymerization solvent such as ethylbenzene, toluene, xylene, etc. Further, it is also possible to use an organic peroxide commonly used in the polymerization of styrenic polymers together with the above-mentioned low-temperature decomposition type organic peroxide. It can also be added during the polymerization.

As the polymerization method, a bulk polymerization method or a solution polymerization method, which is commonly used in the production of styrenic polymers, is used. Either a batch polymerization method or a continuous polymerization method can be used. Examples of the styrenic monomer of the present invention include styrene, α-methylstyrene, p-t-butylstyrene, p-
-Methylstyrene etc. can be used. These styrenic monomers can be used alone or in combination. As acrylic ester (methacrylic ester) monomer,
Butyl acrylate, butyl methacrylate, etc. can be used. These acrylic ester (methacrylic ester) monomers can be used alone or in combination.

The polymerization solution leaving the reactor is led to a recovery device. As the recovery device, devices commonly used in the production of styrenic resins, such as a flash tank system, an extruder with a multi-stage vent, etc., can be used. As for the operating conditions, the same conditions as in the production of styrenic resin can be used. Additives commonly used for styrenic polymers, such as antioxidants, lubricants, plasticizers, colorants, and antistatic agents, may be added at any stage before or after recovering unreacted monomers and/or polymerization solvents. etc. can be added.

In the present invention, (1) The viscosity of a 10% by weight toluene solution, which is a measure of the degree of polymerization, is measured in a high temperature bath at 25° C. using an Ostwald-Cannon-Fenske viscosity tube #350. ■ The particle diameter of the dispersed particles is determined by a transmission electron microscope photograph taken using an ultra-thin section method of resin at a magnification of 10.00.
0 was photographed, the number of dispersed particles in the photograph, approximately 1,000 to 2,000, was measured and determined by the following formula. Particle diameter of dispersed particles=ΣDi/n Di=
i-th particle diameter
n=Number of particles in the measured particles Note that the dispersed particles shown in the electron micrograph are not perfectly circular, so the particle diameter is measured based on the long axis of the particle (
It is calculated by the following formula using the measured values of the lengths of a) and short axis (b).

■ Constituent unit ratio (C)/((A)+(B
)) is measured by the following method. After dissolving the styrene resin in methyl ethyl ketone, add methanol and centrifuge at 20,000 rpm for 30 minutes, separate the supernatant, and add a large amount of methanol to the supernatant to precipitate the styrenic polymer. . This precipitate was heated to 50℃ and 10mmHg.
Dry in a vacuum dryer. Using this sample, 13C is measured using a JASCO Corporation JNM-G400 FT-NMR under the measurement conditions described below. (Measurement of 13C) Pulse width = 9.3 μs; 45° pulse data points = 32768 Repetition time = 2.0 seconds AD converter = 16 bits Number of integration = 30,000 to 100,000 Sample concentration = 20% by weight Solvent = 1 , 1,2,2-tetrachloroethane- (d
2) Sample tube = 10mm Measurement temperature = 120℃

A peak derived from the methylene group of the structural unit (C) appears at 29.4 ppm. On the other hand, structural unit (A)
, (B), a peak derived from the carbon of the methine group and methylene group appears at 39 to 50 ppm. The structural unit ratio: (C)/((A)+(B)) is determined from the peak area ratio.

■ The ratio of structural units (A) and (B) is determined by the following method. A sample is prepared in the same manner as the 13 C measurement, and 1 H is measured using JNM-GX270 FT-NMR under the conditions described below. (1 H measurement) Pulse width = 8.4 μs Data points = 16384 Repetition time = 7.559 seconds AD converter = 16 bits Number of integration = 1,000 Sample concentration = 10% by weight Solvent = 1,1,2,2- Tetrachloroethane (d
2) Sample tube = 5 mm Measurement temperature = 120°C The peak derived from the phenyl group of structural unit (A) is 6.2
Appears at ~7.4 ppm. A peak derived from hydrogen in the structural unit (B) appears at 3.4 to 3.8 ppm. The ratio of the structural unit (A) and the structural unit (B) is determined from the peak area ratio.

The styrenic resin of the present invention can be molded using a known method generally used for molding thermoplastic resins, such as an injection molding machine, an extruder, a casting machine,
Sheets and films can be obtained using T-die processing equipment. In particular, the styrenic resin of the present invention is optimally used for sheets and films. It can also be suitably used for low foam sheets. Furthermore, after being formed into a film, sheet, etc., it can be formed into a desired molded article. In order to improve the surface characteristics of the obtained styrenic resin molded article, especially a film or sheet, an antistatic agent or a lubricant such as silicone may be applied.

The physical property testing methods used in the examples are described below. Melt flow rate (MFR): ISO R1133
According to. Vicat Softening Point (VICAT): ASTM D152
According to 5. Single blow impact strength: Molding temperature = 240℃, Molding pressure = SSP
+5kg/cm2, mold temperature = 60℃ 5cm×
A test piece of 8.8 cm x 2 mm was injection molded, and a missile with a mass of 6.5 kg was naturally dropped from a height of 20 cm using a "dropping weight type graphic impact tester" manufactured by Toyo Seiki Seisakusho to determine the maximum load for destruction. demand. In the case of a sheet, a 5 cm x 8.8 cm sample is cut out from the sheet and measured according to the above method.

[0036]

Examples 1 to 4 Styrenic resins were polymerized using the apparatus shown in FIG. 1 attached. Polymerization reactors-1 and 1' are complete mixing type reactors, each with a capacity of 30L, and
The reaction solution volume can be varied within a range of 25L. Polymerization reactors 2 and 2' are tubular reactors with a built-in static mixer, and each has a capacity of 20 L. In order to mix the polymerization solution and the polymerization initiator solution, a static mixer was installed at the inlet of the polymerization reactor-2', and its capacity was 1 L. A gear pump is installed at the outlet of the polymerization reactors -1, -1', -2 and the recovery system.

Polymerization is carried out under the polymerization conditions shown in Table 1. The rubber-like elastic body is B-S type (B = butadiene block, S = styrene block), and the styrene content is 38
% by weight of rubbery polymer. The particle diameter of the dispersed particles is controlled by the stirring number of the polymerization reactor-1. The polymerization solution exiting the polymerization reactor-2' is led to a preheater. The preheater has a built-in static mixer and has a capacity of 0.8L. After being heated to 240°C in a preheater, it is led to a recovery device kept at 240°C, where it is devolatilized under a vacuum of 10 mmHg and pelletized. The polymer concentration in the polymerization solution is shown in Table 1.
Table 2 shows the evaluation of the physical properties of the styrene resin.

[0038]

[Table 1]

(Note) ■ SM = styrene; BA = butyl methacrylate; rubber = rubbery elastomer; EB = ethylbenzene; CAT = polymerization initiator. Those marked with (*) in CAT are 1,1-bis(t-butylperoxy)cyclohexane. ■#: Add a 1% by weight ethylbenzene solution of 1,1-bis(t-butylperoxy)cyclohexane to a mixer installed in front of reactor-2' so that the polymerization initiator concentration is 100 ppm based on the total field amount. This means the operation of adding additionally.

[0040]

[Example 5] The procedure of Example 3 was repeated except that the stirring speed of reactor-1 was different, and pellets were collected. Table 2 shows the physical property evaluation results.

[Example 6] 50% of the pellets obtained in Example 3 and Example 5 were
The mixture was granulated and mixed using an extruder at a ratio of % by weight/50% by weight. Table 2 shows the physical property evaluation results.

[Example 7] Implemented except that the composition fielded in reactor-1 was 83.6 parts by weight of styrene, 11.5 parts by weight of butyl acrylate, 2.2 parts by weight of rubber-like elastic material, and 2.7 parts by weight of ethylbenzene. Pellets were obtained in the same manner as in Example 3. The polymer concentration in the polymerization solution leaving reactor-2' is 80% by weight. Table 2 shows the physical property evaluation results.

[0041]

[Example 8] This was carried out except that the composition fielded in reactor-1 was 80.0 parts by weight of styrene, 11.5 parts by weight of butyl acrylate, 6.6 parts by weight of rubber-like elastic material, and 2.4 parts by weight of ethylbenzene. Pellets were obtained in the same manner as in Example 3. The polymer concentration in the polymerization solution leaving reactor-2' is 81% by weight. Table 2 shows the physical property evaluation results.

[Comparative Examples 1 to 3] The same procedure as in Example 1 was conducted under the polymerization conditions shown in Table 1, and pellets were collected. The polymerization results are shown in Table 1.
Table 2 shows the physical property evaluation results.

[Comparative Example 4] An experiment was conducted using an apparatus in which the polymerization solution leaving reactor-1 enters the recovery system. 88.3 parts by weight of styrene, 8.7 parts by weight of butyl acrylate, 3 parts by weight of ethylbenzene
．． 0 parts by weight, 0.02 parts by weight of 1,1-bis(t-butylperoxy)cyclohexane were supplied, and the polymerization temperature was 125%.
Pellets were collected in the same manner as in Example 1, except that the polymerization was carried out at 5 hours at a temperature of 5 hours. Table 2 shows the physical property evaluation results.

[0042]

[Comparative Example 5] Polystyrene; Styron G8102 manufactured by Asahi Kasei Industries, Ltd. was used. Table 2 shows the physical property evaluation results.

[Comparative Example 6] Styron G8102 and Asaflex 810, a styrene-butadiene block copolymer manufactured by Asahi Kasei Corporation, are mixed in a ratio of 90/10 (wt%), granulated using a short-shaft extruder, and pellets are collected. . Table 2 shows the physical property evaluation results.

[Comparative Example 7] Styron G8102 and Asaflex 8
Pellets were collected in the same manner as in Comparative Example 6, except that the mixing ratio of 10 to 10 was 80/20. Table 2 shows the physical property evaluation results.
Shown below.

[Comparative Example 8] Pellets were collected in the same manner as in Example 3, except that the stirring number of reactor-1 was different. Table 2 shows the physical property evaluation results.

[0043]

[Table 2]

The styrenic resin of the present invention has a structural unit (B)
As the amount increases, the fluidity improves and the strength also increases. If the structural unit (C) does not exist or is present in a very small amount, no improvement in strength will be observed. Moreover, the particle size of the rubber-like elastic body is 1
If it is smaller than μm, almost no strength improvement effect is observed. The styrenic resin of the present invention has significantly improved strength compared to the polystyrene/styrene-butadiene copolymer mixture that has been widely used in the past.

[0045]

[Example 9] The styrenic polymer collected in Example 1 was
It was extruded using a 0 mmφ extruder to create a sheet with a thickness of 0.7 mm. This sheet was thermoformed using a hot plate air pressure forming machine. The sheet was heated at a heating pressure of 1.0 kg/cm2, molded under conditions of a molding pressure of 2.5 kg/cm2, a molding time of 2 seconds, and a mold temperature of 60°C.
The hot plate temperature of 115℃ allows the hinge 3R to be reproduced exactly like the mold.
, the heating time at 130°C was determined. In addition, the single impact strength of the obtained sheet was determined. The results are shown in Table 3.

[0046]

Example 10 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 2 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

Example 11 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 3 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

Example 12 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 5 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

Example 13 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 6 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

Example 14 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 7 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[0047]

Example 15 Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Example 8 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[Example 16] The composition fed to reactor-1 is 77.9 parts by weight of styrene, 14.6 parts by weight of butyl acrylate, 5.0 parts by weight of rubber-like elastic material, 2.5 parts by weight of ethylbenzene, 1,1- Bis(t-butylperoxy)cyclohexane is 0.01 part by weight, and the composition fed to reactor-1' is 97.0 parts by weight of styrene, 3.0 parts by weight of butyl acrylate, and the polyfunctional resin used in Example 3. Operated in the same manner as in Example 3 except that the type polymerization initiator was 0.2 parts by weight,
Obtained pellets. The polymer concentrations in the polymerization solutions exiting reactors-1, 1', and 2' are 42, 44, and 80% by weight, respectively. Using this resin, thermoforming is performed in the same manner as in Example 9. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3. In addition, the proportion of the structural unit (B) of the styrene resin used = 12.4% by weight, the structural unit ratio [(C)
/((A)+(B))]=0.00019, rubber-like elastic body content=6.1% by weight, dispersed particle size=0.3 μm, M
FR=2.7g/10min, VICAT=85°C.

[0048]

[Comparative Example 9] Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Comparative Example 1 was used. Also, Example 9
In the same manner as above, the single blow impact strength was determined. The results are shown in Table 3.

[Comparative Example 10] Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Comparative Example 3 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[Comparative Example 11] Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Comparative Example 5 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[Comparative Example 12] Thermoforming was carried out in the same manner as in Example 9, except that 3.5 parts by weight of white mineral oil was mixed with 100 parts by weight of the resin used in Comparative Example 5, and a styrene resin was used that was granulated using a single screw extruder. I do. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3. Note that the MFR of the styrene resin used was 2.4 g/10 minutes, and the VICAT was 91°C.

[0049]

[Comparative Example 13] Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Comparative Example 6 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[Comparative Example 14] Thermoforming was carried out in the same manner as in Example 9, except that the styrene resin sampled in Comparative Example 7 was used. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3.

[Comparative Example 15] Thermoforming was carried out in the same manner as in Example 9, except that the styrenic resin collected in the same manner as in Example 3 was used, except that the stirring number of reactor 1 was different. In addition, the single blow impact strength was determined in the same manner as in Example 9. The results are shown in Table 3. In addition, the ratio of the structural unit (B) of the styrene resin used = 8
．． 1% by weight, structural unit ratio [(C)/((A)+(B))]
] = 0.00021, rubber-like elastic body content = 6.0% by weight, dispersed particle size = 1.9 μm, MFR = 2.2 g/10
minutes, VICAT=88°C.

[0050]

[Table 3]

Transparency: Determined by visual inspection ◎: Good transparency ○: Inferior to ◎, but at a level that poses no problem in practical use △: Slightly cloudy, level with restrictions on usage ×: Difficult to use in fields that require transparency level

The styrenic resin of the present invention can be molded at low temperatures and can be molded at a higher speed than conventional styrene resins. In particular, by containing the structural unit (B) in an amount of about 12% by weight, it can be molded under conditions similar to those of vinyl chloride resin. Moreover, the resin of the present invention is
The strength-transparency balance is significantly improved.

[Comparative Example 16] As a rubber-like elastic body, B-S type was used.
Using a rubbery polymer with a styrene content of 10% by weight, the operation was carried out in the same manner as in Example 3, except that the stirring number was changed,
Collect pellets. Table 4 shows the physical property measurement results.

[0053]

[Comparative Example 17] As a rubber-like elastic body, B-S type was used.
Using a rubbery polymer with a styrene content of 60% by weight, the operation was carried out in the same manner as in Example 3, except that the stirring number was changed,
Collect pellets. Table 4 shows the physical property measurement results.

[0054]

[Table 4] Injection molded product, sheet impact strength, and transparency in Example 1
, measured in the same manner as in Example 9.

If the proportion of the vinyl aromatic hydrocarbon polymer block in the rubber-like elastic body is less than 20% by weight, it is substantially opaque, and if it exceeds 50% by weight, it becomes difficult to control the particle size. , it was not possible to form a dispersed phase having a particle size of 0.1 μm or more. As a result, the strength was reduced.

[0056]

[Effects of the Invention] The styrenic resin of the present invention can be molded at low temperatures, and the molding cycle can be shortened. At the same time, the strength is significantly improved. In particular, the sheet has significantly improved transparency and strength balance compared to the conventional styrene-based resin mixed with a styrene-butadiene block copolymer. The styrenic resin of the present invention is a resin with excellent moldability, strength, and transparency.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a polymerization apparatus used in Examples of the present invention.

[Explanation of symbols]

1,1' Complete mixing type reactor 2 Tubular reactor with built-in static mixer 3 Devolatilization tank 4-1~2 Raw material solution feed pump 4-3 Polymerization initiator solution feed pump 5-1~4 Polymerization solution transfer Pumps 6, 10 Molten resin transfer pump 7 Static mixer 8 Preheater (built-in static mixer) 9 Vacuum line

Claims (1)

[Claims] Claim 1: It has a polymer block mainly composed of a vinyl aromatic hydrocarbon polymer block and a conjugated diene, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene is 20:80.
In a rubber-modified styrenic resin containing a rubber-like elastomer with a ratio of ~50:50 as dispersed particles, the continuous phase is (A) [Formula 1] (wherein, R1 is hydrogen or a methyl group, and R2 is hydrogen or It is an alkyl group having 1 to 5 carbon atoms.) (B): (In the formula, R3 is hydrogen or a methyl group, and R4 is an alkyl group having 1 to 8 carbon atoms.However, when R3 is a methyl group , R4 is an alkyl group having 2 to 8 carbon atoms.)(C): (wherein, l and n are integers of 1 to 20, and m is 0 or 1 to 5
is an integer. R5, R6, R7, and R8 are each hydrogen, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group. ) Consisting of the structural units shown in (A), (B)
The ratio of (A): 80 to 99.5% by weight (B):
0.5 to 20% by weight [however, (A) + (B) = 100% by weight], and the structural unit ratio (C) / [(A) + (B)] = 0.01 to 0.0
0001, and the dispersed particle size of the dispersed phase is 0.1 to 0.0001.
An excellent rubber-modified styrenic resin characterized by having a diameter of 1.2 μm and a rubber-like elastic material content of 1 to 20% by weight.