JP2018193428A - Blow molding containing rubber-modified styrene resin composition - Google Patents

Abstract

To provide a blow molding which has less defects by a gel-like substance, hardly causes cutting and thickness deviation of a parison, and is excellent in drawdown resistance.SOLUTION: A blow molding contains a rubber-modified styrene-based resin containing rubbery elastic body particles (B) as dispersion particles in a matrix phase (A), where the matrix phase (A) contains a rubber-modified styrene-based resin composition which contains a styrene-based copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 850-100,000 and one or more monovinyl compounds containing at least a styrenic compound and contains 2.5-11.0 mass% of the rubbery elastic body particles (B).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blow molded article containing a specific rubber-modified styrenic resin composition. Specifically, an object of the present invention is to provide a blow molded product that has few defects due to a gel-like substance, is less likely to cause parison cuts and uneven thickness, and has excellent draw-down resistance.

  Styrenic resins, especially rubber-modified styrenic resins (HIPS), have high rigidity, good dimensional stability, good colorability, and are inexpensive.・ Widely used for industrial parts.

  In recent years, due to the trend of the times when integration of parts is strongly required due to the enlargement of products and the omission of assembly process, for example, more advanced and complicated things are also required in injection molding technology . However, in order to mold using these technologies, a large and complex mold and attached equipment are required, so a great investment is required, and product design and prototyping are not easy. is there.

  On the other hand, blow molding (blow molding) is also a technique attracting attention from the viewpoint of large molding. The advantages of blow molding are that a relatively large molded product can be easily obtained, the investment in the mold is cheaper than that of injection molding, and the mold processing is easy. In blow molding, there is a problem of so-called “draw down” in which, when a parison is created, the parison itself cannot withstand its own weight, and is unbalanced and sometimes cuts. Molding materials inferior to “drawdown resistance” that easily cause drawdown tend to cause uneven thickness and cause parison breakage.

  As an attempt to solve the above problems, for example, Patent Document 1 discloses the weight average molecular weight of the matrix phase of the rubber-modified styrenic resin, the ratio of the weight average molecular weight to the number average molecular weight, and dispersion. A method of controlling the median diameter of rubber-like elastic particles contained as particles and the gel content within an appropriate range has been proposed. Patent Document 2 uses, as a matrix phase, a polymer in which an ultrahigh molecular weight multi-branched copolymer is introduced into a linear polymer composed of a styrene-containing monovinyl compound using a specific polyfunctional vinyl compound copolymer. A rubber-modified styrenic resin composition for highly branched blow molding has been proposed.

JP 2002-097340 A JP 2013-100136 A

  However, the technique disclosed in Patent Document 1 is not sufficient for improving the drawdown resistance, and further improvement of moldability is required. Further, in the technique disclosed in Patent Document 2, since a multi-branched structure is introduced into the molecule, the molecular weight of the polymer tends to be inevitably high, and it is essentially difficult to control the gel-like substance. is there.

  Since the gel-like substance may act as a starting point of craze when blow-molding, there is a demand for a molding material with few defects due to the gel-like substance and excellent in blow moldability.

  The present invention has been devised in view of such conventional circumstances, and the present invention is a blow that has few defects caused by gel-like substances, is less likely to cause parison breakage and uneven thickness, and has excellent draw-down resistance. The object is to provide a molded product.

As a result of diligent research to achieve the above object, the present inventors have configured the matrix phase of the rubber-modified styrenic resin composition with a predetermined conjugated divinyl compound and a predetermined monovinyl compound at an appropriate content ratio. At the same time, by controlling the molecular weight and molecular weight distribution of the matrix phase to an appropriate range, there are few defects caused by gel-like substances, parison breakage and uneven thickness are less likely to occur, and blow molding resistance is excellent. The present inventors have found that a product can be obtained, and have completed the present invention.
That is, the present invention is as follows.

[1]
Including a rubber-modified styrenic resin containing rubber-like elastic particles (B) as dispersed particles in the matrix phase (A),
The matrix phase (A) includes a styrene copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 850 to 100,000 and at least one monovinyl compound including at least a styrene compound,
A blow molded article comprising a rubber-modified styrene resin composition containing 2.5 to 11.0% by mass of the rubber-like elastic particles (B).
[2]
The styrene copolymer forming the matrix phase (A) has a weight average molecular weight (Mw) of 200,000 to 350,000, a ratio of a molecular weight of 2 million or more is 0.2 to 3.6%, and the conjugate The blow molded product according to [1], wherein the ratio of the divinyl compound is 1.2 × 10 ^{−6 to} 2.4 × 10 ⁻⁴ mol with respect to 1 mol of the total amount of the monovinyl compound.
[3]
The blow molded product according to [1] or [2], wherein the conjugated divinyl compound has a number average molecular weight (Mn) of 1000 to 30000.
[4]
The blow molded product according to any one of [1] to [3], wherein the conjugated divinyl compound is a chain.
[5]
The blow molded product according to any one of [1] to [4], wherein a conjugated vinyl group of the conjugated divinyl compound is located at a terminal.
[6]
The blow according to any one of [1] to [5], wherein the ratio of the Z average molecular weight (Mz) to Mw of the styrene copolymer forming the matrix phase (A) is 1.8 to 5.0. Molding.
[7]
The blow molded article according to any one of [1] to [6], wherein the ratio of the styrene copolymer forming the matrix phase (A) having a molecular weight of 1,000,000 or more is 3.4 to 10.0%.
[8]
[1] to [7] The strain at the beginning of the rising of the styrenic copolymer forming the matrix phase (A) is 0.2 to 1.3, and the maximum rising ratio is 1.2 to 5.0. The blow molded product according to any one of the above.
[9]
The blow molded product according to any one of [1] to [8], wherein the conjugated divinyl compound is (hydrogenated) polybutadiene di (meth) acrylate.
[10]
[1] to [9], wherein 0.05 to 0.8 parts by weight of a fatty acid metal salt and 0.05 to 3 parts by weight of liquid paraffin are added to 100 parts by weight of the rubber-modified styrenic resin. The blow molded product according to any one of the above.

  According to the present invention, it is possible to provide a blow-molded product that has few defects due to a gel-like substance, is less likely to cause parison cuts and uneven thickness, and has excellent draw-down resistance.

It is a figure which shows the logarithm graph which plotted the horizontal axis | shaft and the vertical axis | shaft as elongation viscosity about the styrene-type copolymer obtained by the Example and the comparative example.

  Hereinafter, although an embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described, the present invention is not limited to this embodiment.

  The blow-molded product of the present embodiment includes the rubber-modified styrene resin composition of the present embodiment, preferably the rubber-modified styrene resin composition of the present embodiment.

<Rubber-modified styrenic resin composition>
The rubber-modified styrene resin composition of this embodiment includes a rubber-modified styrene resin containing rubber-like elastic particles as dispersed particles in the matrix phase, and (A) the matrix phase has a number average molecular weight (Mn) of 850. A styrene-based copolymer of a conjugated divinyl compound of ˜100,000 and at least one monovinyl compound including at least a styrene compound, and (B) 2.5 to 11.0% by mass of a rubber-like elastic body. .

In the present disclosure, the term “rubber-modified styrene resin composition” is a composition containing a rubber-modified styrene resin. “Rubber-modified styrenic resin” includes a matrix phase containing a styrene copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 850 to 100,000 and at least one monovinyl compound containing at least a styrene compound. And a dispersed phase of rubber-like elastic particles dispersed in the matrix phase.
The rubber-modified styrenic resin is typically obtained by 1) copolymerizing the conjugated divinyl compound with a styrenic monomer and optionally an additional monomer in the presence of a rubber-like elastic body. 2) i) the presence of a styrene copolymer obtained by copolymerizing the conjugated divinyl compound and one or more monovinyl compounds containing at least a styrene compound; and ii) the presence of a rubbery polymer. Below, a conventional rubber-modified styrene resin (HIPS) that does not contain the conjugated divinyl compound obtained by polymerizing a styrene monomer and optionally an additional monomer is converted into a single screw extruder or a twin screw extruder. Or a kneading method using a known kneader such as a Banbury mixer.

  The rubber-modified styrenic resin composition contained in the blow-molded product of the present embodiment has the above-described configuration, so there are few defects due to the gel-like substance, parison breakage and uneven thickness hardly occur, and resistance to drawdown. Excellent.

  Furthermore, according to the present invention, a stable large-scale blow molding capable of beautifully and faithfully reproducing the uneven shape, the edge shape of those corners, and the R shape even for a portion that is stretched many times during blow molding. Goods can be obtained efficiently.

  In addition, it can evaluate by the method as described in the Example mentioned later about a parison state, uneven thickness, mold release property, a molded article external appearance, and scratch resistance, for example.

<Matrix phase>
The styrenic copolymer forming the matrix phase of the rubber-modified styrenic resin composition contained in the blow molded article of the present embodiment is a conjugated divinyl compound having a number average molecular weight (Mn) of 850 to 100,000, and at least a styrenic A styrene copolymer with at least one monovinyl compound containing the compound is included.

In this embodiment, by forming a styrene copolymer that forms a matrix phase with a predetermined conjugated divinyl compound and a predetermined monovinyl compound at an appropriate content ratio, there are few defects due to a gel-like substance, the parison is cut, and It is possible to provide a blow molded product that is less prone to uneven thickness and has excellent draw down resistance.
Specifically, although not limited to theory, in this embodiment, a styrene copolymer obtained by copolymerizing a predetermined conjugated divinyl compound and a predetermined monovinyl compound is mainly composed of a monovinyl compound. A plurality of molecular chain portions and a conjugated divinyl compound interconnecting the molecular chain portions, and the distance between the two molecular chain portions at that time is set to a predetermined distance. (It is presumed that a branched portion having an “H” shape can be easily introduced into the styrene copolymer molecule).
By forming the styrene copolymer in this way, each molecule of the styrene copolymer is likely to be effectively entangled with each other (this effect is also referred to as “entanglement effect”). The draw down resistance of the blow molded product containing the styrene copolymer as a matrix phase can be improved.

<Monovinyl compound>
The styrene copolymer of the present embodiment includes at least one monovinyl compound (as a monomer forming the styrene copolymer) including at least a styrene compound, and the monovinyl compound is a styrene compound. Even if it consists only of (monomer), it may consist of the compound which has another monovinyl group copolymerizable with a styrene type compound with a styrene type compound.
The monovinyl compound is not particularly limited as long as it can be copolymerized with a styrene compound in addition to a styrene compound, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and cetyl (meth). Examples thereof include vinyl compounds such as acrylate and (meth) acrylonitrile, and dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleic anhydride, maleimide, and nucleus-substituted maleimide. Examples of the styrene compound include styrene, α-methyl styrene, paramethyl styrene, ethyl styrene, propyl styrene, butyl styrene, chlorostyrene, and bromostyrene, and styrene is preferable.
Moreover, as content of a styrene-type compound, 50 mol% or more is preferable among content of a monovinyl compound, More preferably, it is 70 mol% or more, More preferably, it is 90 mol% or more.

<Conjugated divinyl compound>
The conjugated divinyl compound in the present embodiment is a compound having a number average molecular weight (Mn) of 850 to 100,000 and having at least two conjugated vinyl groups in the molecule.
In addition, the conjugated divinyl compound in the present embodiment is preferably not a network but a chain, and the main chain may or may not have a side chain. This is because the chain shape allows the molecular chain to have a more linear shape, which tends to improve the entanglement effect. For example, the side chain preferably has 6 or less carbon atoms, and more preferably 4 or less carbon atoms.

  Furthermore, the conjugated vinyl group in the conjugated divinyl compound can be positioned arbitrarily in the molecule, but two of the at least two conjugated vinyl groups are located at different ends in the molecule. It is preferable. When the conjugated divinyl compound is a chain, the two conjugated vinyl groups are more preferably located at different ends of the main chain (that is, both ends of the main chain are conjugated divinyl groups). More preferably). When the conjugated vinyl group is located at the terminal, the polymerization reactivity can be increased.

  Furthermore, when the conjugated divinyl compound is a chain polymer and has three or more conjugated vinyl groups, two of the three or more conjugated vinyl groups may be located at the terminal. Preferably, all of the three or more conjugated vinyl groups are more preferably located at the terminal.

  In addition, when the number of conjugated vinyl groups in the conjugated divinyl compound is large, the branch point increases, and there is a possibility that gelation is likely to occur in the reactor, the molding machine, and the process of recovering the raw material. The machine needs to be cleaned, which may reduce productivity. From these viewpoints, the number of conjugated vinyl groups contained in the conjugated divinyl compound is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, and 2 It is particularly preferred.

  Here, in the present specification, the term “terminal” for a molecule includes not only the position (atom) at the end of the molecule but also a position close to the position at the end of the molecule, Specifically, means the end corresponding to 20% of the extended chain length of the molecule. The conjugated vinyl group in the conjugated divinyl compound is located at the end corresponding to 15% of the extended chain length of the conjugated divinyl compound molecule from the viewpoint of improving the reactivity with the monovinyl compound and suppressing gelation. More preferably, it is located at the end corresponding to 10%, more preferably located at the end corresponding to 5%.

In this embodiment, the conjugated vinyl group refers to an olefinic double bond copolymerizable with a monovinyl compound and a structure that forms a conjugated system with the olefinic double bond (for example, a carbonyl group, an aryl group, etc. ).
The conjugated vinyl group is not particularly limited, and examples thereof include an acryloyl group and an aryl group substituted with a vinyl group, and the structure having a conjugated vinyl group in the conjugated divinyl compound is not particularly limited. , (Meth) acrylate, urethane (meth) acrylate, aromatic vinyl, maleic acid, fumaric acid and the like. The at least two conjugated vinyl groups may be the same or different from each other.

The number average molecular weight (Mn) of the conjugated divinyl compound of this embodiment is 850 to 100,000, preferably 1000 to 100,000, more preferably 1000 to 80000, still more preferably 1200 to 80000, still more preferably 1500 to 60000, particularly preferably. Is 1500-30000. When the number average molecular weight (Mn) is less than 850, since the distance between the conjugated vinyl groups of the conjugated divinyl compound is short, the distance between the polymer chains bonded to the conjugated divinyl compound becomes short, and a sufficient entanglement effect cannot be obtained. Inferior to moldability. When the molecular weight exceeds 100,000, the distance between the conjugated vinyl groups of the conjugated divinyl compound becomes longer, and the reactivity of the conjugated vinyl group at the terminal is lowered (the molecular weight of the conjugated divinyl compound is large, so the terminal conjugated vinyl group reacts). Undesirably), the amount of high molecular weight components produced decreases, which is not preferable.
In addition, the number average molecular weight (Mn) of a conjugated divinyl compound means the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC).

  The main chain structure of the conjugated divinyl compound of the present embodiment is not particularly limited, and examples thereof include polyolefins such as polyethylene, polypropylene and polyisoprene, polystyrene, polybutadiene, hydrogenated polybutadiene, polyphenylene ether, polyester, polyphenylene sulfide and the like. .

Specific examples of the conjugated divinyl compound include (hydrogenated) polybutadiene-terminated (meth) acrylate (“(hydrogenated)” refers to a hydrogenated or non-hydrogenated compound; the same applies hereinafter), polyethylene. Terminal di (meth) acrylate compounds such as glycol terminal (meth) acrylate, polypropylene glycol terminal (meth) acrylate, ethoxylated bisphenol A terminal (meth) acrylate, and ethoxylated bisphenol F terminal (meth) acrylate, and (hydrogenated) Polybutadiene terminated urethane acrylate, polyethylene glycol terminated urethane acrylate, polypropylene glycol terminated urethane acrylate, ethoxylated bisphenol A terminated urethane acrylate, and ethoxylated bisphenol F terminated urethane acrylate Over preparative terminated urethane acrylate compounds such as and the like. For example, in the case of polypropylene glycol terminal (meth) acrylate, the number of bonds of propylene glycol as a repeating unit is determined so that the number average molecular weight (Mn) is 850 to 100,000. The conjugated divinyl compound is preferably (hydrogenated) polybutadiene-terminated (meth) acrylate, polystyrene-terminated (meth) acrylate, or polyphenylene ether-terminated divinyl from the viewpoint of compatibility with the styrene copolymer.
“Terminal” and “both ends” in the compound name mean that a conjugated vinyl group is located at both ends.

<Rubber elastic particles>
The rubber-like elastic particles of the rubber-modified styrenic resin composition contained in the blow-molded product of the present embodiment include a styrene copolymer inside the rubber-like elastic body, and a styrene monomer outside. Is graft polymerized.

  The content of the rubber-like elastic particles is 2.5 to 11.0% by mass, preferably 4.0 to 9.0% by mass, and more preferably 4.9% with respect to the mass of the rubber-modified styrenic resin composition. It is -9.0 mass%. If it is less than 2.5% by mass, the impact resistance will be insufficient, and this will cause cracking of the product, which is not preferable. Moreover, when it exceeds 11.0 mass%, rigidity will fall remarkably and the flaw resistance of the surface of a blow molded product will also fall, and it is not preferable.

As the rubber-like elastic body, polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used, and polybutadiene or styrene-butadiene copolymer is preferable. As the polybutadiene, both high cis polybutadiene having a high cis content and low cis polybutadiene having a low cis content can be used. Moreover, as a structure of a styrene-butadiene copolymer, both a random structure and a block structure can be used. One or more of these rubber-like elastic bodies can be used. A saturated rubber obtained by hydrogenating a butadiene rubber can also be used.
In particular, a block copolymer of a styrene-butadiene copolymer can be used in the polymerization process, or can be added to the rubber-modified styrene resin after polymerization. In the case of additional addition, the addition amount is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the rubber-modified styrene resin. This block copolymer of styrene-butadiene copolymer is commercially available, and examples thereof include “Tufprene” available from Asahi Kasei Corporation.

  Further, two or more kinds of polymers having different molecular weight distribution and different rubber amounts may be combined with the matrix phase containing the styrene copolymer. For example, blending a rubber-modified polystyrene having a rubber-like elastic body amount of 13% by mass and an average particle diameter of 1.4 μm with a rubber non-reinforced styrene copolymer at 50:50 results in In the matrix phase, the amount of rubber-like elastic body is 6.5% by mass, and the average particle diameter of dispersed particles is 1.4 μm, which is included in the scope of the present invention.

<Content of conjugated divinyl compound in matrix phase>
The content of the conjugated divinyl compound in the styrene copolymer forming the matrix phase of the present embodiment is 1.2 × 10 ^{−6 to} 2.4 × 10 ⁻⁴ mol with respect to 1 mol of the total amount of monovinyl compounds. It is preferably 0.9 × 10 ^{−5 to} 1.5 × 10 ⁻⁴ mol, more preferably 1.2 × 10 ^{−5 to} 1.2 × 10 ⁻⁴ mol. When the content is 1.2 × 10 ^{−6 to} 2.4 × 10 ⁻⁴ mol, the ratio of the high molecular weight resin and the viscoelasticity are appropriately controlled, so that the molding processability and the appearance of the molded product are improved. Can do.
In the present disclosure, the content of the conjugated divinyl compound with respect to 1 mol of the total amount of the monovinyl compound is a value measured using ¹ H-NMR and ¹³ C-NMR.

<Molecular weight of the matrix phase>
The weight average molecular weight (Mw) of the styrene copolymer that forms the matrix phase of the present embodiment is 200,000 to 350,000, preferably 220,000 to 330,000, more preferably 230,000 to 320,000. By setting the Mw of the styrenic copolymer to 200,000 to 350,000, it is possible to improve the moldability and fluidity by suppressing the generation of the gel substance while ensuring the strength of the matrix phase.
Further, the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) of the styrene copolymer forming the matrix phase of the present embodiment is preferably 1.8 to 5.0, more preferably 2 .3 to 5.0, more preferably 3.0 to 4.7. By making the ratio of Mz to Mw of the styrene-based copolymer in the range of 1.8 to 5.0, it is possible to suppress the generation of gel-like substance while ensuring the strength of the matrix phase, and more moldability and fluidity. Can be improved.
In the styrene copolymer forming the matrix phase of the present embodiment, the weight average molecular weight (Mw) and the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) (Mz / Mw) are as follows: When radically polymerizing styrenic monomers, the type and amount of conjugated divinyl compound, reaction temperature, residence time, type and amount of polymerization initiator, type and amount of solvent, type and amount of chain transfer agent Etc. can be controlled. Specifically, control of the above weight average molecular weight (Mw) and the like is not limited. For example, in the production method, the amount of polymerization initiator added during polymerization is increased, and the reaction temperature of the polymerization is increased. It can be controlled by lowering, or by reducing the amount of polymerization solvent used, or by increasing the residence time during polymerization, etc., and in this way, in the styrene copolymer obtained The high molecular weight component can be appropriately increased while making the molecular chain into a desired shape.
In addition, the weight average molecular weight (Mw), Z average molecular weight (Mz) of the styrene-type copolymer which forms a matrix phase, the ratio of the below-mentioned molecular weight 1 million or more, and the ratio of 2 million or more are gel permeation chromatography ( GPC) is the weight percentage of the differential molecular weight distribution measured.

<Ratio of high molecular weight component of matrix phase>
The proportion of the styrene copolymer of this embodiment having a molecular weight of 2 million or more is preferably 0.2 to 3.6%, more preferably 0.9 to 3.6%, and 1.2 to More preferably, it is 2.3%. By setting the ratio of the molecular weight of 2 million or more in the range of 0.2 to 3.6%, the content of the gel substance can be extremely reduced.
Moreover, it is preferable that the ratio of molecular weight 1 million or more is 3.4 to 10.0%, It is more preferable that it is 4.5 to 8.3%, 5.5 to 7.6% is still more preferable. By setting the ratio of the molecular weight of 1 million or more in the range of 3.4 to 10.0%, a matrix phase excellent in molding processability and fluidity can be obtained.
The molecular weight ratio of the styrene copolymer forming the matrix phase of the present embodiment is determined based on the type and amount of the conjugated divinyl compound, the reaction temperature, the residence time, the polymerization, when radically polymerizing the styrene monomer. It can be controlled by the type and amount of initiator, the type and amount of solvent, the type and amount of chain transfer agent, and the like. Specifically, the control of the ratio of the molecular weight of 2 million or more and the molecular weight of 1 million or more is not limited. For example, in the production method, the amount of polymerization initiator added during polymerization is increased. It can be controlled by lowering the polymerization reaction temperature, decreasing the amount of polymerization solvent used, or increasing the residence time during polymerization, etc. In the styrene-based copolymer, the low molecular weight component side can be reduced, and the high molecular weight component side can be increased while appropriately adjusting the ratio of the molecular weight of 2 million or more and the molecular weight of 1 million or more.

<Starting strain, maximum rising strain, and maximum rising ratio of the styrene copolymer forming the matrix phase of the rubber-modified styrenic resin composition contained in the blow molded product>
What is the rubber-modified styrenic resin composition contained in the blow molded product of this embodiment? As a component containing about 90 to 1% by mass of a prepolymerized styrene copolymer and rubber, rubber-reinforced aromatic vinyl resin such as HIPS resin and MBS resin, and aromatic vinyl thermoplastic elastomer 1 to 90 such as SBS You may knead | mix and prepare about mass%.
In this case, the strain at the beginning of the rising of the prepolymerized styrenic copolymer is preferably 0.2 to 1.3, more preferably 0.3 to 1.1, and still more preferably 0.4 to 1. 0.
In the specification of the present application, the “strain at the beginning of rising” is a strain that causes strain hardening and is an index of molding processability. The smaller the strain at the beginning of the rise, in other words, the quicker the rise, the strain hardening occurs from the time of low stretching, and the blow molding property is excellent, so the uneven thickness of the molded product may not easily occur, and therefore the molded product can be made thinner. There is.

The maximum rising ratio of the styrene copolymer in the above case is preferably 1.2 to 5.0, more preferably 1.3 to 4.8, and still more preferably 1.4 to 4.6.
In the present specification, the “maximum rising ratio” means (extension viscosity in the nonlinear region of the maximum rising strain / extension viscosity in the linear region of the maximum rising strain), and “maximum rising strain” means that the extension viscosity is the maximum. This means Henkey distortion. The maximum rise ratio is an index representing the degree of strain hardening at the maximum rise strain. The greater the maximum rise ratio, the greater the degree of strain hardening and the better the blow moldability. When the maximum rise ratio is 1.2 or more, the elongational viscosity increases when the strain is high, that is, when the resin is thinly stretched during molding, so that the molded product is less likely to be uneven and the parison is also cut. There is a tendency to become difficult. When the maximum rise is 5.0 or less, the elongational viscosity at the time of molding does not become too high, which is preferable from the viewpoint of the balance between productivity and moldability.

  In particular, depending on the design shape of the concavo-convex portion of the large blow-molded product, a portion that is stretched several times during blow molding may occur. In the first place, the styrene resin has an appropriate molecular weight distribution, so that the elongation at the time of melting is good, but the elongation viscosity is further increased by introducing a styrene copolymer into the matrix phase of the rubber-modified styrene resin of this embodiment. Therefore, it is possible to beautifully and faithfully reproduce the concavo-convex shape, the edge shape of the corner portion, and the R shape even for such a portion that is extended several times.

<Average particle diameter of dispersed particles>
The average particle diameter of the rubber-like elastic particles contained as dispersed particles in the rubber-modified styrenic resin composition contained in the blow molded product of this embodiment is preferably 0.5 to 2.5 μm, more preferably 0.7. It is -2.3 micrometers, More preferably, it is 0.8-2.0 micrometers. By setting the thickness in the range of 0.5 to 2.5 μm, a material excellent in rigidity, mechanical strength and gloss can be obtained. The rubber particle size is determined by the number of revolutions of the stirrer in the reactor, the molecular weight of the rubber-like polymer used, the 1,2-vinyl bond content, and the initiator in the region (phase transition) in which the rubber-like dispersed particles are formed in the polymerization step. It can be adjusted by the type and addition amount, the type and addition amount of the chain transfer agent, and the like.
In the present disclosure, the average particle diameter is a value measured from a transmission electron micrograph by an ultrathin section method.

<Additives>
In the rubber-modified styrenic resin composition contained in the blow-molded product of this embodiment, for example, 2- [1- (2-hydroxy-3] is used in order to suppress thermal decomposition of the polymer in the unreacted monomer recovery step. , 5-di-t-phenylpentyl) ethyl] -4,6-di-t-phenylpentyl acrylate may be included.
In addition, additives commonly used in the field of styrenic resins, for example, higher fatty acids such as stearic acid, zinc stearate, calcium stearate, magnesium stearate, salts thereof, lubricants such as ethylenebisstearylamide, plastics such as liquid paraffin, etc. An agent and an antioxidant may be added in combination as long as the purpose of the present embodiment is not impaired.

Antioxidants generally stabilize peroxide radicals such as hydroperoxy radicals generated during thermoforming or exposure to light, or decompose peroxides such as hydroperoxides generated. It is a possible ingredient. Although it does not specifically limit as antioxidant, For example, a hindered phenolic antioxidant and a peroxide decomposer are mentioned. The hindered phenolic antioxidant is a radical chain inhibitor, and the peroxide decomposer can decompose the peroxide generated in the system into more stable alcohols to prevent autooxidation.
Examples of the hindered phenol antioxidant include, but are not limited to, 2,6-di-tert-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3-t-butyl-2-hydroxy-5- Methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, 4,4 ′ -Butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), alkylated bisphenol Tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane and 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-] 5-methylphenyl) -propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxyspiro [5.5] undecane and the like.
Examples of the peroxide decomposer include, but are not limited to, organic phosphorus peroxide decomposition such as trisnonylphenyl phosphite, triphenyl phosphite, and tris (2,4-di-t-butylphenyl) phosphite. As well as dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopro Pionate), ditridecyl-3,3′-thiodipropionate, and organic sulfur peroxide decomposers such as 2-mercaptobenzimidazole.
The addition amount of the antioxidant is 0.01 parts by mass or more and 1 part by mass with respect to 100 parts by mass of the styrene copolymer forming the matrix phase of the rubber-modified styrenic resin composition contained in the blow molded product of this embodiment. The amount is preferably not more than mass parts, more preferably not less than 0.1 parts by mass and not more than 0.5 parts by mass.

  In particular, it is preferable to add a fatty acid metal salt and liquid paraffin as additives to the rubber-modified styrenic resin contained in the blow-molded product of this embodiment.

The fatty acid metal salt is added mainly for the purpose of improving releasability. Large blow molded products generally have a long side of about 1 m, and in some cases, a large molded product larger than that is also assumed. If it becomes a large-sized molded product, the “biting” to the mold is strong accordingly, and it is extremely important from the viewpoint of industrial productivity that the mold releasability is good.
The amount of fatty acid metal salt added is preferably 0.05 to 0.8 parts by weight, more preferably 0.1 to 0.5 parts, based on 100 parts by weight of the rubber-modified styrenic resin contained in the blow molded product. Part by mass. By adding 0.05 to 0.8 mass of fatty acid metal salt to 100 mass parts of rubber-modified styrenic resin, the mold release effect of the blow molded product is maintained while maintaining the high weld strength of the blow molded product. Can be increased.

  The fatty acid metal salt used in the present invention is at least one selected from the group consisting of calcium, magnesium, and zinc, and at least one fatty acid selected from the group of fatty acids having 12 to 22 carbon atoms. Among them, zinc stearate, zinc palmitate and the like are particularly preferable because of excellent release effect and thermal stability of the molding material.

On the other hand, liquid paraffin is added for the purpose of improving scratch resistance derived from surface slipperiness. Specifically, the addition of liquid paraffin improves surface lubricity and scratch resistance.
The addition amount of liquid paraffin is 0.05-3 mass parts normally with respect to 100 mass parts of rubber-modified styrene-type resins contained in a blow molded product, More desirably, it is 0.5-2 mass parts. By adding 0.05 to 3 parts by mass of liquid paraffin to 100 parts by mass of rubber-modified styrenic resin, blow molding with excellent scratch resistance is achieved with minimal reduction in elongational viscosity during melting. Goods can be obtained.

  The liquid paraffin can be selected from, for example, liquid paraffin defined by standard standards such as the Food Sanitation Law, food, and additives. Specific examples of this type of liquid paraffin include, but are not limited to, Cristol N52, Cristol N62, Cristol N72, Cristol N82, Cristol N122, Cristol N172, Crystall, commercially available from ExxonMobil. Stall N262, cristol N352, prime mall N542 and the like. Moresco White P-40, Moresco White P-55, Moresco White P-60, Moresco White P-70, Moresco White P-80, Mores, which are commercially available from Matsumura Oil Research Co., Ltd. Sco White P-85, Moresco White P-100, Moresco White P-120, Moresco White P-150, Moresco White P-200, Moresco White P-230, Moresco White P-260, Moresco White P-300, Moresco white P-350, Moresco white P-350P, etc. are mentioned. Further, liquid paraffin 40-S, 60-S, 70-S, 80-S, 90-S, 100-S, 120-S, 150-S, 260-S commercially available from Sanko Chemical Co., Ltd. 350-S. Furthermore, white mineral oil commercially available from CK Witco Corporation can be mentioned.

The molecular weight of the liquid paraffin is usually defined by kinematic viscosity. The liquid paraffin in the present embodiment, for example, a kinematic viscosity of 40 ° C. which is defined by the test method JIS K2283 is able to use a range of 0.1~60mm ² / sec, the 1~40mm ² / sec Those are preferred. Moreover, the preferable weight average molecular weight of a liquid paraffin is the range of 150-500, More preferably, it is the range of 180-450, More preferably, it is the range of 200-350. A weight average molecular weight is calculated | required by taking the weight average value of each molecular weight component of a liquid paraffin, for example using gas chromatography. When using liquid paraffin of this viscosity range or molecular weight range, the resulting rubber-modified styrene resin composition is greatly plasticized as compared with liquid paraffin of higher viscosity or higher molecular weight, and the rubber-modified styrene resin composition This tends to greatly improve the blow moldability, for example, the surface gloss of the blow molded product. The use of liquid paraffin having a viscosity of 0.1 mm ² / sec or more or a weight average molecular weight of 150 or more is effective for mold contamination and bleeding on the surface of the molded product during molding of the resulting rubber-modified styrene resin composition. This is preferable because there is a tendency to suppress it.

<Method for Producing Rubber-Modified Styrene Resin Composition>
The method for producing a rubber-modified styrene resin contained in the blow molded article of this embodiment is as follows: 1) In the presence of a rubbery elastic body, the conjugated divinyl compound, a styrene monomer, and optionally an additional monomer; 2) i) a styrene copolymer obtained by copolymerizing the above conjugated divinyl compound and at least one monovinyl compound containing at least a styrene compound, ii) a conventional rubber-modified styrenic resin (HIPS) containing no conjugated divinyl compound obtained by polymerizing a styrene monomer and optionally an additional monomer in the presence of a rubber-like polymer; Examples thereof include a melt kneading method using a known kneader such as a single screw extruder, a twin screw extruder, and a Banbury mixer.

  In the above method 1), the raw material solution contains a monovinyl compound containing a styrene compound, a rubber-like elastic body, and a conjugated divinyl compound. The conjugated divinyl compound, which is a constituent element of the rubber-modified styrene resin composition contained in the blow molded article of the present embodiment, is dissolved in a monovinyl compound, a polymerization solvent, or the like, and optionally in the middle of the reactor. Can also be added.

From the viewpoint of controlling the polymerization reaction, a polymerization initiator such as a polymerization solvent or an organic peroxide or a chain transfer agent can be used as necessary.
The polymerization solvent is used for adjusting the polymerization rate, molecular weight and the like in continuous bulk polymerization and continuous solution polymerization. The polymerization solvent is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, dialkyl ketones such as methyl ethyl ketone, and each may be used alone or in combination of two or more. You may use it in combination.
Furthermore, other solvents such as aliphatic hydrocarbons can be mixed with the aromatic hydrocarbons within a range that does not lower the solubility of the polymerization product. These solvents are preferably used in an amount not exceeding 25% by mass relative to the monomer. When the solvent exceeds 25% by mass, the polymerization rate is remarkably reduced, and the impact strength of the resulting resin is greatly reduced.
Moreover, since a large amount of energy is required for the recovery of the solvent, the economy is inferior. The solvent may be added after the polymerization proceeds and becomes relatively high in viscosity, or may be added before the polymerization, but is added at a rate of 5 to 20% by mass before the polymerization. However, it is easier to make the quality uniform, and this is preferable from the viewpoint of controlling the polymerization temperature.

  In particular, when it is desired to increase the amount of the conjugated divinyl compound added, it is preferable to use a polymerization solvent from the viewpoint of suppressing gelation. Thereby, the addition amount of the conjugated divinyl compound shown above can be increased, and a gel is hardly generated.

The polymerization initiator is not particularly limited, but organic peroxides such as 2,2-bis (t-butylperoxy) butane, 1,1-bis (t-butylperoxy) cyclohexane (PHC), and n-butyl. Peroxyketals such as -4,4-bis (t-butylperoxy) valerate, dialkyl peroxides such as di-t-butyl peroxide (PBD), t-butylcumyl peroxide, dicumyl peroxide, acetyl peroxide, isobutyryl Diacyl peroxides such as peroxides, peroxydicarbonates such as diisopropylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, hydroperoxides such as t-butylhydroperoxide Mention may be made of the earth and the like.
The polymerization initiator is preferably added in an amount of 0.005 to 0.08 mass% with respect to the styrene monomer.

Examples of the chain transfer agent include α-methylstyrene linear dimer (αMSD), n-dodecyl mercaptan, t-dodecyl mercaptan, 1-phenyl-2-fluorene, dibenten, chloroform and other mercaptans, terpenes, halogen compounds, terpinolene. And the like.
The amount of the chain transfer agent used is not particularly limited, but it is generally preferable to add about 0.005 to 0.3% by mass with respect to the monomer.

As an example of a more specific production method, a monovinyl compound containing a styrene compound in which a rubber-like polymer is dissolved, a conjugated divinyl compound, and a polymerization solvent, a polymerization catalyst, a chain transfer agent, and the like are added and mixed as necessary. Then, the monomers are continuously fed into an equipment equipped with one or more reactors arranged in series and / or in parallel and a devolatilization process for removing unreacted monomers, etc. A so-called continuous bulk polymerization method in which the polymerization is allowed to proceed is preferably used. Examples of the reactor type include a complete mixing type, a laminar flow type, and a loop type reactor in which a part of the polymerization liquid is extracted while the polymerization proceeds. Although there is no restriction | limiting in particular in the order of arrangement | sequence of these reactors, A laminar flow type reactor is used suitably.
In the devolatilization process, a vacuum devolatilization tank or a devolatilization extruder with a heater is generally used. For example, one using only one stage of a vacuum devolatilization tank with a heater, one connecting two stages of vacuum devolatilization tanks with a heater, or a vacuum devolatilization tank and a devolatilization extruder with a heater In order to reduce the volatile content as much as possible, a vacuum devolatilization tank with a heater or a vacuum devolatilization tank with a heater is connected in series. What connected the devolatilization extruder in series is preferable.

Examples of the method for producing a styrene copolymer in the method 2) include known styrene polymerization methods such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method. These polymerization methods may be batch polymerization methods or continuous polymerization methods, and are preferably continuous polymerization methods from the viewpoint of productivity.
As the continuous bulk polymerization method, for example, a monovinyl compound, a conjugated divinyl compound, a solvent, a polymerization catalyst, a chain transfer agent, and the like are added and mixed as necessary to prepare a raw material solution containing monomers. In a facility equipped with one or more reactors arranged in series and / or in parallel and a devolatilizer for a devolatilization step for removing volatile components such as unreacted monomers, the raw material solution is added. Examples of the method include continuous feeding and stepwise polymerization.

Next, an example of a conventional method for producing a rubber-modified styrene resin (HIPS) that does not contain the conjugated divinyl compound in the method 2) will be described. In a typical embodiment, the rubber-modified styrenic resin composition comprises a sea island in which a styrene monomer is polymerized in the presence of a rubbery polymer, and the rubbery polymer is dispersed in the styrene polymer. It can be manufactured by a method that includes forming a structure. There is no restriction | limiting in particular about the polymerization method of a styrene-type monomer, A normal block polymerization, solution polymerization, suspension polymerization, etc. can be performed using the solution which melt | dissolved rubber | gum in the styrene-type monomer.
Moreover, in order to adjust the fluidity at the time of melting, it is preferable to select and use a solvent and a chain transfer agent as appropriate.
As the solvent, toluene, ethylbenzene, xylene or the like can be used. Although the usage-amount of a solvent is not specifically limited, Use of the range of 0-50 mass% is preferable on the basis of 100 mass% of total quantity of a polymerization raw material liquid.
As the chain transfer agent, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer or the like is used, and α-methylstyrene dimer is preferable. The amount of the chain transfer agent used is preferably 0.01 to 2% by mass, more preferably 0.03 to 1% by mass, and still more preferably 0.05 to 0.2%, based on 100% by mass of the total amount of the polymerization raw material liquid. It is the range of mass%.
The polymerization reaction temperature is preferably in the range of 80 to 200 ° C, more preferably 90 to 180 ° C. If the reaction temperature is 80 ° C. or higher, the productivity is good and industrially suitable. On the other hand, if it is 200 ° C. or lower, the formation of a large amount of low molecular weight polymer can be avoided. When the target molecular weight of the styrenic polymer cannot be adjusted only by the polymerization temperature, it may be controlled by the initiator amount, the solvent amount, the chain transfer agent amount, and the like. The reaction time is generally 0.5 to 20 hours, preferably 2 to 10 hours. If the reaction time is 0.5 hours or longer, the reaction proceeds satisfactorily. On the other hand, if the reaction time is 20 hours or shorter, the productivity is good and industrially suitable.

In this embodiment, it is preferable to add the phenol-based thermal deterioration inhibitor in the polymerization step or the devolatilization step, and after the polymerization step and before the devolatilization step. It is more preferable to add a phenol-based heat deterioration inhibitor after the polymerization step (preferably immediately after) and before the devolatilization step.
Examples of the phenol-based thermal degradation inhibitor include 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (trade names: Sumilizer GM, Sumitomo Chemical). 2- [1- (2-hydroxy-3,5-di-t-phenylpentyl) ethyl] -4,6-di-t-phenylpentyl acrylate (trade name: Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.) ).
The addition amount is preferably 0.01 to 0.5% by mass, more preferably 0.02 to 0.3% by mass, and still more preferably 0.000% by mass with respect to the styrene copolymer at the outlet of the final reactor. It is 03-0.2 mass%.
When the addition amount of the phenol-based thermal deterioration inhibitor is 0.01 to 0.5% by mass, the production of the monovinyl compound and its dimer or trimer in the devolatilization step is more effectively suppressed. Can do.

(Devolatilization process)
As the devolatilization device, for example, a normal devolatilization device such as a flash drum, a biaxial devolatilizer, a thin film evaporator, an extruder, or the like can be used. A volatile extruder or the like is used. Examples of the arrangement of the devolatilizer include, for example, one using a vacuum devolatilization tank with a heater, one connected in series with two vacuum devolatilization tanks with a heater, and vacuum devolatilization with a heater. The thing etc. which connected the volatilization tank and the devolatilization extruder in series are mentioned. In order to reduce volatile components as much as possible, a vacuum devolatilization tank with a heater connected in two stages in series or a vacuum devolatilization tank with a heater and a devolatilization extruder connected in series is preferable. .
The conditions for the devolatilization step are not particularly limited. For example, when the polymerization of the styrene copolymer is performed by bulk polymerization, the unreacted monovinyl compound is preferably 50 mass in the styrene copolymer. The polymerization can be continued until it is not more than%, more preferably not more than 40% by mass. By devolatilization treatment, volatile components such as unreacted substances (monovinyl compounds) and / or solvents can be removed.
The temperature of the devolatilization treatment is usually about 190 to 280 ° C. The pressure of the devolatilization treatment is preferably 0.1 to 50 kPa, more preferably 0.13 to 13 kPa, still more preferably 0.13 to 7 kPa, and particularly preferably 0.13 to 1.3 kPa. As the devolatilization method, for example, it is desirable to devolatilize through a method of devolatilization by heating under reduced pressure, an extruder designed to remove volatile components, or the like.

<Blow molded product>
As blow molded products of this embodiment, in addition to the unit bath top panel described above, it is used for unit bath side panels, temporary toilet top and side panels, ski resort lift ticket gates, amusement park ticket gates, etc. Housing panels represented by the top and side panels of outdoor boxes, partitions often used in offices, game machine housings installed in commercial amusement facilities, top and side panels of desks or tables, large TVs TV table top panel, audio rack top panel / bottom panel, bed underlay, storage shelf side plate, doors and caskets in general households, flooring or structural members laid under the floor.
As a specific definition of “large” in the blow molded product of the present invention, the volume of the molded product including the hollow portion when the blow pin portion of the molded product is closed is 10,000 cm ³ or more, and the parison at the time of molding The long side of the blow-molded product that is the extrusion direction is 80 cm or more.
When blow molding is performed, first, a required amount of molten resin is stored in an accumulator (resin reservoir), and a parison is formed through a circular die. In the blow-molded product proposed in the present invention, different material parts represented by metals such as bolts, nuts and screws can be integrated according to the purpose. Although an integration method is not specified in the present invention, a method of blow molding after setting these parts in a mold in advance before molding is general.
Furthermore, the blow-molded product proposed in the present invention can be subjected to secondary processing such as joining, adhesion, cutting, and printing by an arbitrary method. For example, the top panel of the unit bath, which is an application example of the blow molded product of the present embodiment, is obliged to be provided with a drop lid type opening called an inspection port, in addition to the ventilation port. The means for providing the inspection port is not specified in the present invention, but as a general processing method, a method of providing an opening using a cutting device in a molded product is used.

  Hereinafter, although an embodiment of the present invention is described concretely with an example and a comparative example, the present invention is not limited to these examples.

<Measurement and evaluation method>
Measurement and evaluation were performed based on the following methods.

(1) Conjugated divinyl with respect to a monomer unit derived from a monovinyl compound in a matrix phase of a styrene copolymer as a raw material of a rubber-modified styrene resin composition contained in a blow-molded product and a rubber-modified styrene resin composition Measurement of ratio of monomer unit derived from compound Sample preparation of rubber-modified styrene-based resin composition: 1 g of rubber-modified styrene-based resin composition was precisely weighed, and methyl ethyl ketone / methanol mixed solvent medium (mixed weight / mass ratio 90/10) ) After adding 20 mL and shaking at 23 ° C. for 2 hours, it was centrifuged at 10 ° C. or less and 20000 rpm for 60 minutes with a centrifuge (Himac (trade name) CR-20 (rotor: R20A2) manufactured by Hitachi, Ltd.). . The supernatant liquid after centrifugation was reprecipitated in methanol and then filtered to recover the matrix phase of the rubber-modified styrenic resin composition, which was dried.
In addition, when measuring the monomer unit derived from the conjugated divinyl compound with respect to the monomer unit derived from the monovinyl compound of the styrene copolymer used as a raw material, the above sample preparation operation is not performed. The copolymer pellets were used as measurement samples as they were.
In the styrene copolymer or rubber-modified styrene resin composition, the ratio of the monomer unit derived from the conjugated divinyl compound to 1 mol of the total monomer unit derived from the monovinyl compound is ¹ H-NMR and ¹³ C. -Determined using NMR.
As a measuring device, JEOL-ECA500 manufactured by JEOL Ltd. was used. At that time, chloroform-d1 was used as a solvent, and a resonance line of tetramethylsilane was used as an internal standard.

(2) Measurement of molecular weight of matrix phase of conjugated divinyl compound, styrene copolymer, and rubber-modified styrene resin composition Number average molecular weight (Mn) of conjugated divinyl compound, styrene copolymer, and (1) The weight average molecular weight (Mw), the Z average molecular weight (Mz), the ratio of the molecular weight of 1 million or more, and the ratio of the molecular weight of 2 million or more of the matrix phase of the rubber-modified styrene resin composition recovered by the above method are gel permeation. The measurement was performed under the following conditions using chromatography (GPC).
Apparatus: Tosoh HLC-8220
Separation column: Two TOSOH TSK gel Super HZM-H (inner diameter 4.6 mm) connected in series Guard column: TSK guard column Super HZ-H manufactured by Tosoh
Measuring solvent: Tetrahydrofuran (THF)
Sample concentration: 5 mg of measurement sample dissolved in 10 mL of solvent Injection volume: 10 μL
Measurement temperature: 40 ° C
Flow rate: 0.35 mL / min 11 types of TSK standard polystyrenes manufactured by Tosoh (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000) were used. A calibration curve was prepared using an approximate expression of a linear straight line.

(3) Rubber-like elastic particle content 0.4 g of rubber-modified styrenic resin composition was placed in a 100 mL volumetric flask and precisely weighed (W). After 75 mL of chloroform was added and well dispersed, 20 mL of a solution of 18 g of iodine monochloride in 1000 mL of carbon tetrachloride was added and stored in a cool dark place, and after 8 hours, the mark was adjusted to the mark with chloroform. 25 mL of this was collected, 60 mL of a solution in which 10 g of potassium iodide was dissolved in a mixture of 800 mL of water and 200 mL of ethanol was added, and titrated with a solution (molar concentration x) of 10 g of sodium thiosulfate dissolved in 1000 mL of water. The test AmL and the blank test BmL were used, and the rubbery elastic particle content (% by mass) was determined by the following equation.
Rubber-like polymer particle content (% by mass) = 10.8 × xx (BA) / W

(4) Particle size of rubber-like elastic particles 2 to 5 pellets of rubber-modified styrenic resin composition were added to dimethylformamide using COULTER MULTISIZER III (trade name) manufactured by Beckman Coulter Co., Ltd. equipped with an aperture tube having a diameter of 30 μm. It was placed in about 5 mL and left for about 2 to 5 minutes. Next, the dimethylformamide dissolved content was measured as an appropriate particle concentration, and the volume-based median diameter was determined.

(5) Gel-like substance evaluation of solid sheet A 30 mmφ sheet extruder (manufactured by Soken Co., Ltd.) was used to extrude a styrene copolymer to produce a sheet (solid sheet) having a thickness of 0.5 mm. Twenty test pieces were cut out in a size of 100 mm length × 100 mm width from the obtained sheet, and a gel-like substance having an average of a short diameter and a long diameter of 2 mm or more was visually measured. Judgment was made with “◎” when the number of test pieces that contained the gel-like substance was 0-2, “◯” when 3-10, and “x” when 11 or more.

(6) Measurement of Strain and Maximum Rise Ratio of Styrene Copolymer The measurement of the strain and maximum ratio of styrene copolymer was performed based on the following viscoelasticity measurements.
Device name: Viscoelasticity measuring device ARES-G2 (TA Instruments)
Measurement system: ARES-EVF option Test piece dimensions: Length 20mm, thickness 0.7mm, width 10mm
Elongation strain rate: 0.01 / second Temperature: 150 ° C
Measurement atmosphere: in nitrogen stream Preheating time: 1 minute Pre-extension strain rate: 0.05 / sec Pre-extension length: 0.295 mm
Relaxation time after pre-extension: 1 minute In the viscoelasticity measurement, after the test piece was attached to a roller and the temperature was stabilized at the measurement temperature, the sample was allowed to stand for the pre-heating time and pre-heated. After completion of preheating, pre-extension was performed under the above conditions. After pre-extension, it was allowed to stand for 2 minutes, and the stress produced by the pre-extension was relaxed and measured.
Based on the results obtained in the above viscoelasticity measurement, a logarithmic graph in which the horizontal axis is the Henkey strain and the vertical axis is the extensional viscosity is created, and the range where the Henkey strain is 0.2 to 0.5 is a linear region. A linear area straight line for power approximation was created (for example, a broken line in FIG. 1). When strain hardening occurs, the actual extensional viscosity becomes larger than the extensional viscosity of the approximate straight line extrapolating this linear region. Then, when the difference between the extensional viscosity in the non-linear region and the extensional viscosity in the approximate straight line extrapolating the linear region becomes 3% of the extensional viscosity in the non-linear region at the same Henkey strain, the Henkey strain was defined as the strain at the beginning of the rise. The maximum rise ratio is defined as the maximum rise strain as the Henkey strain when the extensional viscosity becomes maximum in the above viscoelasticity measurement (extrapolated linear region in the maximum rise strain / nonlinear region extension viscosity at maximum rise strain) (Elongation viscosity of approximate straight line)
FIG. 1 shows a log-log graph in which the horizontal axis represents Henkey strain and the vertical axis represents elongational viscosity for the styrene copolymers obtained in Examples and Comparative Examples.

(7) Blow moldability The rubber-modified styrene resin composition is plasticized at a temperature of 200 ° C. with a 120 mmφ single screw extruder (L / D = 25), and the rubber is put into a 15 liter accumulator (set temperature: 180 ° C.). The modified styrene resin composition was stored, and a parison was formed from a die having a diameter of 50 mmφ. The size of the blow-molded product was length × width × thickness = 1800 × 900 × 50 mm (product volume 63000 cm ³ ), and the weight was adjusted to about 45 kg. The mold temperature was 70 ° C. and the molding cycle was 4 minutes.
100 pieces of the above-mentioned molded products were prepared, and the situation at this time was compared with the state of the molded body.

a) The state of the parison was confirmed visually.
The determination is “◎” when no parison break is observed, “◯” when less than 5 parison breaks are observed, “Δ” when 5 or less than 20 parison breaks are observed, “Δ”, 20 The case where more than one piece was observed was defined as “x”.

b) The uneven thickness state was evaluated as follows.
The molded product that could be blow-molded was cut, and the thickness ratio between the top and bottom of the parison was measured.
Comparison was made in the average value of the ratio of the upper thickness to the lower parison thickness.
Ratio = (lower wall thickness) / (upper wall thickness)
The determination is “◎” when the average ratio is less than 1.2, “◯” when the average ratio is 1.2 or more and less than 1.5, and “average” when the average ratio is 1.5 or more and less than 1.8. The case where “Δ” and the average ratio were 1.8 or more was “x”.

c) The releasability was evaluated as follows.
The releasability when actually molded by the above molding machine was evaluated.
Judgment is “◎” when the mold is opened and at the same time the molded product is detached from the mold, “○” when the mold is opened, but “○” when it is at a level where there is no problem in production. The case where the molded product bites into the mold and is manual is indicated as “Δ”.

d) The appearance (gloss) of the molded product was confirmed visually.
The determination was “◯” when the image was very glossy and beautiful, “Δ” when the image was glossy but spotted, and “X” when the image was not glossy and looked matte.

e) As for scratch resistance, the surface of a molded product colored with a titanium oxide master batch was strongly scratched with a fingernail, and the presence or absence of a scratch (mark) was visually evaluated.
In the determination, “◯” indicates that no scratch is visible, “Δ” indicates that there is a scratch but there is no practical problem, and “×” indicates that the scratch is conspicuous.

<Material>
In the examples and comparative examples, the following materials were used.

<Styrene copolymer>
<Conjugated divinyl compound>

(Conjugated divinyl compound 1)
The conjugated divinyl compound 1 was produced based on the following method.
In a 5 L reaction vessel equipped with a stirrer, a thermometer and a reflux condenser, 2742 g of polybutadiene alcohol at both ends (Mn: 1900), 379 g of methyl acrylate, 380 g of n-hexane, 0.8194 g of hydroquinone monomethyl ether, and 4 -0.5533 g of hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl was charged. While passing the obtained mixture through a calcium chloride tube, air was blown into the mixture, and reflux dehydration was performed at 80 to 85 ° C. The moisture contained in this mixture was measured by the Karl Fischer method, and it was confirmed that the water content was 200 ppm or less. Thereafter, 1.36885 g of tetra-n-butyl titanate was added to the above mixture as a transesterification catalyst, and the resulting methanol was stirred out while distilling out of the reaction system under reflux of n-hexane, an azeotropic solvent. And reacted at a reaction temperature of 80 to 85 ° C. for 10 hours.
Next, the temperature in the reaction vessel is adjusted to 75 to 80 ° C., and concentrated at a reduced pressure of 70 to 2 kPa until 95% or more of the used methyl acrylate and n-hexane are distilled off. n-Hexane was recovered. To 2070 g of the polybutadiene diterminated diacrylate thus obtained, 2000 g of toluene, 200 g of acetone, 20 g of ion-exchanged water, and hydrotalcite (composition formula Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O) [Kyowa] Chemical Industry Co., Ltd., trade name: KYOWARD 500PL] 20 g was added and treated at 75-80 ° C. for 2 hours. Next, by adjusting the temperature in the reaction vessel to 75 to 80 ° C. and concentrating at a reduced pressure of 90 to 35 kPa, 400 g of a mixed distillate of toluene, acetone and water is recovered, and the resulting concentrated solution is air. The catalyst and the adsorbent were separated by filtration under pressure, and the solvent was degassed at a temperature of 60 to 80 ° C. and a degree of vacuum of 30 to 0.8 kPa to obtain a conjugated divinyl compound 1.
It was 99.3% when the conversion rate of the polybutadiene both terminal diacrylate of the conjugated divinyl compound 1 was measured by high performance liquid chromatography (HPLC). The number average molecular weight (Mn) in terms of polystyrene measured by GPC was 1900.

Conjugated divinyl compound 2: polybutadiene diacrylate [manufactured by Sakai Kogyo Co., Ltd .: CN307] Mn: 3800
Conjugated divinyl compound 3: Polybutadiene-terminated acrylate [Osaka Organic Chemical Industry: BAC-45] Mn: 4800
Conjugated divinyl compound 4: urethane acrylate oligomer [manufactured by Sakai Kogyo Co., Ltd .: CN9014NS] Mn: 8000

(Conjugated divinyl compound 5)
The conjugated divinyl compound 5 was produced based on the following method.
The conjugated divinyl compound 5 produced under the same conditions as in the case of the conjugated divinyl compound 1 except that the molecular weight of the polybutadiene alcohol at both ends was changed to Mn: 25000 had a conversion rate of 99.5% of the polybutadiene both ends diacrylate. It was. Moreover, the number average molecular weight (Mn) of polystyrene conversion measured by GPC was 26000.

(Conjugated divinyl compound 6)
The conjugated divinyl compound 6 was produced based on the following method.
The conjugated divinyl compound 6 produced under the same conditions as in the case of the conjugated divinyl compound 1 except that the molecular weight of the polybutadiene alcohol at both ends was changed to Mn: 57000 had a conversion rate of polybutadiene diterminal diacrylate of 99.2%. It was. Further, the number average molecular weight (Mn) in terms of polystyrene measured by GPC was 58,000.

Conjugated divinyl compound 7: Aromatic urethane acrylate [Sakai Kogyo Co., Ltd .: CN9782] Mn: 5200
Conjugated divinyl compound 8: Reaction product of (2,2 ′, 3,3 ′, 5,5′-hexamethylbiphenyl-4,4′-diol · 2,6-dimethylphenol polycondensate) and chloromethylstyrene [Mitsubishi Gas Chemical Co., Ltd .: OPE-2ST] Mn: 1200
Conjugated divinyl compound 9: 1,3-butylenediol dimethacrylate [manufactured by Wako Pure Chemical Industries, Ltd.] Molecular weight: 226
Conjugated divinyl compound 10: NK ester A-GLY-20E [manufactured by Shin-Nakamura Chemical Co., Ltd.] Molecular weight: 1295, the average number of conjugated vinyls in one molecule of conjugated divinyl compound 10 is 3.
Conjugated divinyl compound 11: Divinylbenzene [Wako Pure Chemical Industries, Ltd.] Molecular weight: 130
Conjugated divinyl compound 12: Polyethylene glycol dimethacrylate [manufactured by Sigma-Aldrich] Molecular weight: 750
In addition, the conjugated divinyl compounds 2 to 9, 11, and 12 had a conjugated vinyl group at both ends of the molecule.

<Monovinyl compound>
Styrene: Styrene monomer [Asahi Kasei Corporation]

<Rubber elastic body>
HIPS1: H0104 manufactured by PS Japan
HIPS2: 403R made by PS Japan
HIPS3: PS Japan Co., Ltd. H8117
HIPS4: HT478 manufactured by PS Japan
HIPS5: 475D made by PS Japan
(HIPS6)
HIPS6 was manufactured based on the following method.
Styrene 77.66% by mass as a styrene monomer, 9.19% by mass of polybutadiene rubber (BR15HB manufactured by Ube Industries), 12.0% by mass of ethylbenzene as a solvent, liquid paraffin as a plasticizer / additive (CP-68N manufactured by Idemitsu Kosan Co., Ltd.) 0.90% by mass, 1,4-bis (t-butylperoxy) cyclohexane 0.004% by mass as a polymerization initiator, and α-methylstyrene dimer 0.10 as a chain transfer agent A 6.2-liter laminar flow reactor equipped with a stirrer and capable of controlling the temperature in three zones is prepared by mixing and dissolving 0.15% by mass of Irganox 1076 (manufactured by BASF Japan) as an antioxidant. −1 was continuously charged at 3.2 liters / hr, and the temperature was adjusted to 117 ° C./123° C./129° C. The rotation speed of the stirrer was 50 rotations per minute. The reaction rate at the reactor outlet was 30%.
Subsequently, the reaction solution was sent to a 6.2 liter laminar flow reactor-2 connected in series with the laminar flow reactor-1 and equipped with a stirrer and capable of temperature control in three zones. The number of revolutions of the stirrer was 15 revolutions per minute, and the temperature was set to 136 ° C / 138 ° C / 140 ° C. Subsequently, the reaction solution was sent to a 6.2 liter laminar flow reactor-3 equipped with a stirrer and capable of controlling the temperature in three zones. The number of revolutions of the stirrer was 10 revolutions per minute, and the temperature was set to 147 ° C / 156 ° C / 159 ° C.
The polymer solution continuously discharged from the polymerization reactor (laminar flow reactor-3) was devolatilized and pelletized under reduced pressure of 1.5 to 2.0 kPa with an extruder with a vacuum vent. The temperature of the extruder was set at 235 ° C.
The polymerization conditions are shown in Table 3 below.

<Additives>
Thermal degradation inhibitor 1: 2- [1- (2-hydroxy-3,5-di-t-phenylpentyl) ethyl] -4,6-di-t-phenylpentyl acrylate [Sumitomo Chemical Co., Ltd .: Sumilyzer GS ]
Thermal degradation inhibitor 2: Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate [Ciba Specialty Chemicals: IRGANOX1076]

<Others>
Polymerization initiator 1: 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane [manufactured by NOF Corporation: Pertetra A]
Polymerization initiator 2: 1,1-di- (t-butylperoxy) cyclohexane [manufactured by NOF Corporation: Perhexa C]

<Example 1>
<Styrene copolymer 1>
80 parts by mass of styrene, 20 parts by mass of ethylbenzene, 0.035 parts by mass of conjugated divinyl compound 1 (2.4 × 10 ⁻⁵ mol per 1 mol of styrene), and 0.030 parts by mass of polymerization initiator 1 were added. A raw material solution was prepared. The prepared raw material solution was continuously supplied at 1.00 L / hr to a fully mixed first reactor having an internal volume of 5.4 L maintained at a temperature of 105 ° C. Next, the polymerization solution from the first reactor was supplied to a plug flow type second reactor having an internal volume of 3 L in the order in which the raw material solution passed through. In the second reactor, the temperatures of the three zones were maintained at 119, 133, and 143 ° C. in the order in which the raw material solutions passed. In the second zone, 0.03 parts by mass of polymerization initiator 2 was added. Next, the polymerization solution from the second reactor was supplied to a vacuum degassing tank heated to a temperature of 240 ° C., volatile components such as unreacted monomers and solvents were removed, and after continuous operation for 72 hours, Styrene copolymer 1 was obtained.
The production conditions and analysis results of the styrene copolymer 1 are shown in Table 1.
Next, the mass ratio of the styrene copolymer 1 and the HIPS1 shown in Table 1 is 60/40, and 0.2 parts by mass of zinc stearate and 0.5 parts by weight of liquid paraffin with respect to 100 parts by mass of the mixed resin. A rubber-modified styrene resin composition was obtained by adding mass parts and kneading at 200 ° C. and 150 rpm using a twin-screw extruder (TEM26SS-12-2V) manufactured by Toshiba Machine Co., Ltd.
Evaluation was performed by the method of said (1)-(7). Table 1 shows the physical properties and evaluation results of the rubber-modified styrene resin composition of Example 1.

<Examples 2 to 14>
Examples 2 to 14 were carried out in the same manner as in Example 1 except that the conditions were changed as shown in Table 1, and rubber-modified styrenic resin compositions were prepared.
Table 1 summarizes the measurement and evaluation results of Examples 2-14.
In addition, as for the styrene-type copolymer of Example 4, as shown in FIG. 1, it turns out that the strain hardening was expressed in the measurement of ARES-EVF.

<Examples 15 to 21>
Examples 15 to 21 were carried out in the same manner as in Example 1 except that the conditions were changed as shown in Table 2, and rubber-modified styrenic resin compositions and blow-molded products thereof were prepared.
In addition, the styrene-type copolymer created in Example 9 was used for all the styrene-type copolymers used in Examples 15-21.

<Comparative Examples 1-8>
Comparative Examples 1-8 were carried out in the same manner as in Example 1 except that the conditions were changed as shown in Table 5 using an existing styrene polymer without using a styrene copolymer, and rubber was used. A modified styrene resin composition and its blow molded product were prepared.
In addition, the following were used for the styrenic polymer used in Comparative Examples 1-8.
Styrene polymer 1: G9401 manufactured by PS Japan Co., Ltd.
Styrene polymer 2: G9305 manufactured by PS Japan Co., Ltd.
Styrene polymer 3: G8102 manufactured by PS Japan

<Comparative Examples 9-14>
Comparative Examples 9 to 14 were performed in the same manner as in Example 1 except that the conditions were changed as shown in Table 6, and rubber-modified styrenic resin compositions were prepared.
The measurement and evaluation results of Comparative Examples 9 to 14 are summarized in Table 6.

<Comparative Examples 15-16>
Comparative Examples 15 to 16 were performed in the same manner as in Example 1 except that the conditions were changed as shown in Table 5, and rubber-modified styrenic resin compositions and blow-molded products thereof were prepared.
In addition, all the styrene copolymers used in Comparative Examples 15 to 16 were the styrene copolymers prepared in Example 9. Moreover, the following were used for HIPS used by Comparative Examples 15-16.

<Example 22>
Styrene monomer 88.7 parts by mass, ethylbenzene 9 parts by mass, conjugated divinyl compound 4 0.48 parts by mass (7.03 × 10 ⁻⁵ mol per 1 mol of styrene), polybutadiene [manufactured by Asahi Kasei Corporation: diene 55], 0.016 parts by weight of polymerization initiator 2 and 0.02 parts by weight of chain transfer agent 1 were added to prepare a raw material solution.
The adjusted raw material solution was continuously supplied at 3 L / hr to a 6.2 L laminar flow reactor-1 equipped with a stirrer and temperature controlled in 3 zones, and the temperature was adjusted to 122 ° C./128° C./134° C. It was adjusted. The rotational speed of the stirrer was 100 revolutions per minute. The reaction rate at the outlet of the reactor was 31%. Subsequently, the reaction solution was sent to a 6.2 L laminar flow reactor-2 equipped with a stirrer connected in series with the laminar flow reactor-1 and capable of controlling the temperature in three zones. The number of revolutions of the stirrer was 15 revolutions per minute, and the temperature was 147 ° C / 150 ° C / 153 ° C. Subsequently, the reaction solution was sent to a 6.2 L laminar flow reactor-3 equipped with a stirrer connected in series with the laminar flow reactor-2 and capable of temperature control in three zones. The number of revolutions of the stirrer was 10 revolutions per minute, and the temperature was 155 ° C / 162 ° C / 164 ° C. Subsequently, the reaction solution from the laminar flow reactor-3 is supplied to an extruder with a two-stage vacuum vent adjusted to 220 ° C. and 1.5 to 2.0 kPa to remove volatile components such as unreacted monomers and solvents. The resin extruded into a strand shape was cut to obtain pellets.
Next, 0.2 parts by mass of zinc stearate powder is added to 100 parts by mass of the obtained rubber-modified styrenic resin, and a Henschel mixer FM10C / I type manufactured by Mitsui Mining Co., Ltd. is used at 600 rpm. The mixture was stirred to obtain a rubber-modified styrene resin composition.
Table 4 shows the production conditions and analysis results of the rubber-modified styrenic resin composition.
Evaluation was performed by the method of said (1)-(7). Table 1 shows the physical properties and evaluation results of the rubber-modified styrenic resin composition of Example 22.

<Comparative Example 17>
Comparative Example 17 was performed in the same manner as in Example 22 except that the conditions were changed as shown in Table 4, and a rubber-modified styrenic resin composition and its blow-molded product were prepared.

As is clear from Tables 5 and 6, the ratio of the monomer units derived from the conjugated divinyl compound to the total amount of 1 mol of monomer units derived from the monovinyl compound is as small as 0 to 1.7 × 10 ⁻⁶ mol. In the styrene copolymer forming the matrix phase of the rubber-modified styrene resin composition contained in the blow molded articles of Comparative Examples 1 to 9, strain hardening was not expressed in the measurement of viscoelasticity by ARES-EVF.
In Comparative Example 10 in which the ratio of the monomer units derived from the conjugated divinyl compound to the total amount of 1 mol of monomer units derived from the monovinyl compound was 4.1 × 10 ⁻⁴ mol, ARES− of the styrene copolymer was used. In the measurement of viscoelasticity by EVF, stable data could not be obtained, and in the measurement of GPC, a large amount of THF-insoluble matter could not be measured, and there were many gel substances. For these reasons, in Comparative Example 10, a rubber-modified styrenic resin composition worthy of evaluation and its blow-molded product could not be prepared.
In Comparative Examples 11 and 14 where the number average molecular weight (Mn) of the conjugated divinyl compound is as small as 226 and 750, the styrene copolymer that forms the matrix phase of the rubber-modified styrene resin composition contained in the blow molded product is used. At the beginning, the strain was large and the maximum rise ratio was small.
Comparative Example 12 in which the ratio of the molecular weight of 2 million or more of the styrene copolymer forming the matrix phase of the rubber-modified styrene resin composition contained in the blow-molded product was increased to 6.39%, and the strain was greatly controlled at the start of rising. Then, there were many gel-like substances of a blow molded product.
In Comparative Example 13 in which the number average molecular weight (Mn) of the conjugated divinyl compound was as small as 130, the melt mass flow rate (MFR) of the blow molded product was small, and there were many gel substances.
In the blow molded product of Comparative Example 15 in which the content of the rubber-like elastic particles is as high as 11.3% by mass and the amount of liquid paraffin added is as high as 4.0% by mass, the parison state and uneven thickness are at the worst level. Although it was not, it was inferior in releasability, appearance of blow molded product, and scratch resistance.
In the blow molded product of Comparative Example 16 in which the content of rubber-like elastic particles is as low as 2.2% by mass and the addition amount of the release agent and liquid paraffin is low, the parison state, uneven thickness, mold release property, molded product The appearance and scratch resistance of all the blow moldability were inferior.
Further, as is apparent from Table 4, in the blow-molded product of Comparative Example 17, the release agent and liquid paraffin were added in appropriate amounts, but the rubber-like elastic particle content was as high as 15.8% by mass. Although the property and appearance of the molded product were not so bad, the parison state, uneven thickness, and scratch resistance were inferior.
On the other hand, as is clear from Tables 1 and 2, the blow-molded products of Examples 1 to 21 were superior to the blow-molded products prepared in Comparative Examples 1 to 17 and were obtained. It can be seen that there is little uneven thickness of the molded body and the product appearance is excellent. Further, as is apparent from Table 4, the blow molded product of Example 22 does not contain liquid paraffin and is inferior in scratch resistance, but the parison state, uneven thickness, releasability, and appearance of the molded product are It turns out that it is in a practical range.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, In the range which does not deviate from the meaning of invention, it can change suitably.

  The blow-molded product of the present embodiment has few defects due to the gel-like substance, is less likely to cause parison cuts and uneven thickness, and has excellent drawdown resistance. Furthermore, since the extensional viscosity is increased by introducing a styrene-based copolymer into the matrix phase of the blow molded product of this embodiment, the uneven shape and the corners thereof are also applied to the portions that are stretched several times during blow molding. A stable large blow-molded product capable of beautifully and faithfully reproducing the edge shape and R shape of the portion can be efficiently obtained, and productivity is improved. From the above, the role that the blow-molded product of this embodiment plays in the industry is large.

Claims (10)

Including a rubber-modified styrenic resin containing rubber-like elastic particles (B) as dispersed particles in the matrix phase (A),
The matrix phase (A) includes a styrene copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 850 to 100,000 and at least one monovinyl compound including at least a styrene compound,
A blow molded article comprising a rubber-modified styrene resin composition containing 2.5 to 11.0% by mass of the rubber-like elastic particles (B). The styrene copolymer forming the matrix phase (A) has a weight average molecular weight (Mw) of 200,000 to 350,000, a ratio of a molecular weight of 2 million or more is 0.2 to 3.6%, and the conjugate The blow-molded article according to claim 1, wherein the proportion of the divinyl compound is 1.2 x ^{10-6 to} 2.4 x ^10-4 mol based on 1 mol of the total amount of the monovinyl compound.   The blow molded product according to claim 1 or 2, wherein the conjugated divinyl compound has a number average molecular weight (Mn) of 1000 to 30000.   The blow molded product according to any one of claims 1 to 3, wherein the conjugated divinyl compound is a chain.   The blow molded product according to any one of claims 1 to 4, wherein a conjugated vinyl group of the conjugated divinyl compound is located at a terminal.   The blow according to any one of claims 1 to 5, wherein the ratio of Z average molecular weight (Mz) to Mw of the styrene copolymer forming the matrix phase (A) is 1.8 to 5.0. Molding.   The blow-molded article according to any one of claims 1 to 6, wherein a ratio of the styrene copolymer forming the matrix phase (A) having a molecular weight of 1,000,000 or more is 3.4 to 10.0%.   The strain at the beginning of the rising of the styrenic copolymer forming the matrix phase (A) is 0.2 to 1.3, and the maximum rising ratio is 1.2 to 5.0. The blow molded product according to claim 1.   The blow-molded article according to any one of claims 1 to 8, wherein the conjugated divinyl compound is (hydrogenated) polybutadiene di (meth) acrylate.   The fatty acid metal salt 0.05 to 0.8 parts by mass and liquid paraffin 0.05 to 3 parts by mass are added to 100 parts by mass of the rubber-modified styrenic resin. The blow molded product according to one item.

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