WO2013069077A1

WO2013069077A1 - Method for producing styrene-based resin composition comprising highly branched ultra-high-molecular-weight polymer, and composition

Info

Publication number: WO2013069077A1
Application number: PCT/JP2011/075578
Authority: WO
Inventors: 圭太秋葉; 敬一林; 川辺　正直
Original assignee: 新日鉄住金化学株式会社
Priority date: 2011-11-07
Filing date: 2011-11-07
Publication date: 2013-05-16
Also published as: CN103917594B; CN103917594A; SG11201402095UA

Abstract

Provided is a styrene-based resin composition with which gelling is controlled and which is formed from a highly branched ultra-high-molecular-weight copolymer and a linear polymer; also provided is a method for producing the same. By means of the method for producing a styrene-based resin composition comprising a highly branched super-high-molecular-weight copolymer and a linear polymer, a styrene-based resin composition is obtained that comprises the following: a highly branched ultra-high-molecular-weight copolymer which is produced by adding 50 to 5,000 ppm by weight standard of a solvent-soluble polyfunctional vinyl copolymer, having an average of two or more vinyl groups per 1 molecule and having a branch structure, to a monovinyl compound whose essential ingredient is styrene to promote polymerization and thereby polymerize the solvent-soluble multifunctional vinyl copolymer and the monovinyl compound; and a linear polymer that is produced by polymerization of the monovinyl compound.

Description

Method for producing styrenic resin composition containing hyperbranched ultrahigh molecular weight substance and composition thereof

The present invention is a highly branched ultra-high polymer obtained by adding and mixing an ethylenically unsaturated monomer containing styrene and a solvent-soluble polyfunctional vinyl copolymer having a plurality of double bonds in one molecule, and proceeding the polymerization. The present invention relates to a method for producing a styrene resin composition comprising a mixture of a molecular weight component and a linear component, and a styrene resin composition obtained by the production method.

Styrenic resins are widely used in many fields such as electrical appliances and household products because they are inexpensive, excellent in transparency, heat resistance, mechanical strength, etc., and have good moldability. These molded products are injection molding or vacuum or pressure molding from a sheet, and further blow molding in which compressed air is blown from the inside after a resin is sandwiched in an extrusion mold called a parison from an extruder. It is obtained by. Further, a technique such as foam molding is also used to obtain a molded body having light weight and heat insulation performance. Styrenic resin foam has many features such as light weight, heat insulation, and cushioning, and is a sheet used for food packaging by being thermoformed from polystyrene foam, which is typified by residential insulation, into trays, bags, etc. Technologies such as bead foaming, in which aliphatic polystyrene such as pentane is directly impregnated into granular polystyrene paper and resin in the particle state obtained by suspension polymerization, and a container is formed by heating such as steam, are widely used. . In these molding methods, there is a high demand for a material having high strain-hardening properties at the time of melting, particularly for molding methods such as sheet molding, blow molding, and foam molding having a melt-drawing process.

When using a resin material with low strain-hardening properties in the above molding method, the problem with sheet molding is that when it is secondarily processed into a deep-drawn molded product such as a food container, the sagging phenomenon associated with heating and melting results in a product. Thickness unevenness is likely to occur, and the product is likely to be cracked or torn due to insufficient stretchability. In blow molding, if the strain hardening is low at the time of parison formation, drawdown occurs and molding becomes difficult. For example, there is a large variation in product strength, and in addition, it is difficult to make the bubbles in the foam smaller and independent in order to enhance the heat insulation performance in foam molding. In order to improve the ratio of closed cells in foam molding, materials that can be stretched are suitable so that there are no extremely thin portions on the wall during stretching, and for materials with low strain hardening, stretching in thinned areas Therefore, once a thin portion is generated, a vicious cycle of further stretching and further thinning occurs, and eventually the wall surface is ruptured. In a material with high strain hardening, the viscosity of the stretched region increases, and the resistance to stretching of the thinned portion is higher than that of the thickened portion, so that the uniform film thickness does not fall into the above-mentioned vicious circle. Can be stretched at

It has long been known that a method of adding an ultrahigh molecular weight component to a styrenic resin composition is effective as a means for improving melting characteristics such as tension in tension and strain hardening.

As a method for obtaining a resin composition containing an ultrahigh molecular weight component, a styrene polymer composition containing a component having a molecular weight of 2 million or more described in Patent Document 1 within a certain range is known. However, as a method of obtaining this composition, bulk polymerization, solution polymerization is used to proceed the polymerization at low temperature to generate an ultrahigh molecular weight component, or an ultrahigh molecular weight adjusted separately by anionic polymerization, emulsion polymerization, etc. A method of mixing components in a molten state has been proposed, but this method has problems such as inferior productivity and high cost when blending separately polymerized components.

In order to avoid the above problem, for example, there is a styrenic polymer containing a molecular weight component of 1 million or more containing a polyfunctional vinyl compound unit described in Patent Document 2 within a certain range. In order to contain a molecular weight component, it has been proposed to polymerize by adding a very small amount of an aromatic polyfunctional vinyl compound typified by an aromatic divinyl compound to a vinyl monomer. However, when this means is applied to continuous bulk polymerization, when a long-term reaction is continued, there is a problem that gelation proceeds in a region where the flow called a boundary film existing on the wall of the polymerization reactor is stopped, When trying to avoid the above, the amount of the polyfunctional aromatic vinyl compound was limited, and it was difficult to produce a desirable amount of ultrahigh molecular weight component. Furthermore, in suspension polymerization, because the polymerization is completed until almost no unreacted monomer is present, when the proposed polyfunctional vinyl compound is applied as it is, the polyfunctional vinyl compound incorporated into the polymer chain at the end of the polymerization. Since the derived pendant vinyl group reacts rapidly in the region where the conversion rate is 90% or more and the molecular weight is significantly increased, it is difficult to control the molecular weight and molecular weight distribution.

Furthermore, Patent Document 3 discloses a method in which an ultrahigh molecular weight component having a branched structure is contained in a styrene polymer using a polyfunctional polymerization initiator by suspension polymerization, and Patent Document 4 also discloses a polyfunctional polymerization initiator. Has been disclosed to contain an ultrahigh molecular weight component having a branched structure in a styrene polymer, but in this method, the entire styrene polymer is likely to have a high molecular weight, and in order to avoid this, a chain transfer agent or the like is used. When a molecular weight regulator is used in combination, the effect tends to be insufficient. Patent Document 5 discloses a method for controlling the degree of polymerization of a styrenic resin by using a polyfunctional aromatic vinyl compound and a chain transfer agent together, but as in the case of using a polyfunctional initiator. In addition to offsetting the effect, the use of mercaptans as chain transfer agents has a problem that the range of use is limited due to the problem of specific odor.

Japanese Patent Publication No.62-61231 Japanese Patent Laid-Open No. 2-170806 JP-A-7-278218 Japanese Patent Application Laid-Open No. 8-59721 JP 2002-241413 A

The object of the present invention is to provide a highly branched ultra-high molecular weight component without gel-like material, which has optimum melting characteristics for processing methods that require a melt-drawing process during molding such as sheet molding, foam molding, blow molding, etc. By providing a styrenic resin composition containing a highly branched ultra-high molecular weight polymer excellent in melting characteristics obtained by the method for efficiently producing a styrenic resin composition containing a linear component and a linear component is there.

That is, the present invention is a method for producing a styrene-based resin composition containing a hyperbranched ultrahigh molecular weight copolymer and a linear polymer, and an average of one molecule is added to a monovinyl compound essentially containing styrene. A solvent-soluble polyfunctional vinyl copolymer having two or more vinyl groups and having a branched structure is added and mixed in an amount of 50 ppm to 5000 ppm on a weight basis to proceed with the polymerization. The present invention relates to a method for producing a styrene resin composition comprising a hyperbranched ultrahigh molecular weight copolymer produced by polymerizing the monovinyl compound and a linear polymer produced by polymerizing the vinyl monomer.

In the above production method, the solvent-soluble polyfunctional vinyl copolymer is obtained by polymerizing a monovinyl compound copolymerizable with a divinyl compound, and is further a pendant vinyl group derived from the divinyl compound represented by the following formula (a1). In the structural unit in the range of 0.05 to 0.50 as the molar fraction, and the ratio of the inertial radius (nm) in the weight average molecular weight to the molar fraction is in the range of 1 to 100 Preferably mentioned.

(In the formula, R ¹ represents a hydrocarbon group derived from a divinyl compound.)

The present invention also relates to a linear styrene-based polymer having a weight-average molecular weight of 2.0 to 20.0 wt% having a weight average molecular weight of 1,000,000 or more obtained by the above production method and a weight average molecular weight of 100,000 to 500,000. The present invention relates to a styrenic resin composition containing a hyperbranched ultrahigh molecular weight copolymer characterized by having a weight average molecular weight of 200,000 to 800,000 containing 80.0 to 98.0 wt% of a polymer.

Hereinafter, the present invention will be described in detail. As a polymerization method used in the present invention, a monovinyl compound containing styrene, a solvent-soluble polyfunctional vinyl copolymer, and, if necessary, a solvent, a polymerization catalyst, a chain transfer agent, and the like are added and mixed in series and / or in parallel. A so-called continuous system in which monomers are continuously fed into an equipment equipped with one or more reactors arranged and a volatile component removing process for removing unreacted monomers, and the polymerization proceeds in stages. A bulk polymerization method is preferably used. Examples of the reactor type include a fully mixed tank reactor, a column reactor having plug flow properties, and a loop reactor in which a part of the polymerization liquid is withdrawn while the polymerization proceeds. There is no particular limitation on the order of arrangement of these reactors, but in order to suppress the formation of gel-like substances in continuous production, the solvent-soluble polyfunctional vinyl copolymer is in an unreacted state, and the film on the reactor wall surface. It is important not to develop a state of staying at a high concentration therein, and it is preferable to select a fully mixed tank reactor as the first reactor.

In the polymerization method of the present invention, a monovinyl compound containing styrene, a solvent-soluble polyfunctional vinyl copolymer, and a polymerization catalyst, a chain transfer agent, and the like are added and mixed as necessary, and then suspended in water for polymerization. A so-called suspension polymerization method for proceeding is also preferably used. In order to stabilize the dispersion, organic dispersants such as polyvinyl alcohol and methyl cellulose, inorganic dispersants such as tricalcium phosphate and magnesium phosphate, and anionic surfactants such as sodium dodecylbenzenesulfonate were dissolved in water. Then, the monomers are added and dispersed under stirring, and the polymerization is allowed to proceed in the range of 100 to 150 ° C. The final polymerization conversion rate at the end of the reaction is desirably 99% or more in consideration of the case where the aliphatic hydrocarbon foaming gas such as pentane is impregnated under pressure in the water dispersion state after the completion of the polymerization. If it is less than 99%, a bad odor is accompanied when the temperature during secondary molding is not lower than the boiling point of the residual monomer.

In the present invention, in order to achieve a final polymerization conversion rate of 99% or more, a raw material in which a peroxide catalyst having a one-hour half-life temperature in the range of 130 ± 10 ° C. is added in an amount of 200 ppm or more with respect to the charged amount of raw material. It is desirable to polymerize the solution at a reaction temperature of 120 ° C. or lower to 50% or higher, and then perform polymerization at a reaction temperature exceeding the catalyst half-life temperature of 5 ° C. or higher for 3 hours or longer. By using these conditions, the final polymerization conversion rate can be easily increased to 99% or more without taking an extremely long polymerization time. When the reaction temperature at the latter stage is not more than 1 hour half-life temperature, the polymerization time becomes extremely long and the productivity is remarkably lowered.

Organic peroxide initiators used to achieve a final conversion of 99% or higher include t-butyl peroxyacetate, t-butyl peroxybenzoate, 2,2-di- (t-butylperoxy) butane, Examples include dicumyl peroxide.

In the present invention, the solvent-soluble polyfunctional vinyl copolymer is dissolved in a monovinyl compound, a polymerization solvent, etc., and if necessary, in the case of continuous bulk polymerization, in the middle of a plurality of reactors, in suspension polymerization, It can also be added during the polymerization reaction.

The monovinyl compound (hereinafter also referred to as a styrene monomer) essential to styrene used in the present invention may be 100% styrene or a mixture containing styrene and another monovinyl compound. Other monovinyl compounds may be those having an olefinic double bond copolymerizable with styrene, such as aromatic vinyl monomers such as paramethylstyrene, acrylic acid monomers such as acrylic acid and methacrylic acid, and acrylonitrile. , Vinyl cyanide monomers such as methacrylonitrile, acrylic monomers such as butyl acrylate and methyl methacrylate, α, β-ethylenically unsaturated carboxylic acids such as maleic anhydride and fumaric acid, imides such as phenylmaleimide and cyclohexylmaleimide Based monomers. These other monovinyl compounds may be used alone or in combination of two or more. The proportions of styrene and other monovinyl compounds are preferably 20 to 100 mol% of styrene and 0 to 80 mol% of other monovinyl compounds in order to take advantage of the characteristics of the styrene resin composition.

The solvent-soluble polyfunctional vinyl copolymer used in the present invention (hereinafter also referred to as polyfunctional vinyl copolymer) is an ultra-high molecular weight styrene resin branched in various ways by being copolymerized with a styrene monomer. Give.

The polyfunctional vinyl copolymer used in the present invention can be obtained according to the methods disclosed in JP-A No. 2004-123873, JP-A No. 2005-213443, WO 2009/110453, and the like. Specifically, a divinyl compound and at least one monovinyl compound are used for copolymerization to obtain a copolymer having a reactive pendant vinyl group represented by the formula (a1). Furthermore, as described in the above-mentioned patent document, those having other terminal groups other than vinyl groups introduced at the terminals can also be used, particularly for compounds having an unsaturated bond in the molecule such as phenoxy methacrylates. In addition to (a1), the terminal-modified one is preferable because it can act as a crosslinking point. In this case, since the terminal unsaturated bond-containing structural unit (a2) also has a vinyl group, the total molar fraction (a3) with the structural unit of the formula (a1) indicates the total amount of vinyl groups present. It will be.

Examples of divinyl compounds used to obtain polyfunctional vinyl copolymers include divinyl aromatic compounds represented by divinylbenzene and aliphatic and alicyclic (meth) acrylates represented by ethylene glycol di (meth) acrylate. Examples are shown.

In addition, examples of the monovinyl compound used here include monovinyl compounds containing a monovinyl aromatic compound such as styrene as described above.

As a method for producing a polyfunctional vinyl copolymer, for example, two or more kinds of compounds selected from divinyl aromatic compounds, monovinyl aromatic compounds and other monovinyl compounds are used as promoters selected from Lewis acid catalysts and ester compounds. It can be obtained by cationic copolymerization in the presence. Further, when a (meth) acrylate divinyl or monovinyl compound is used, the reaction does not proceed in cationic polymerization, and therefore, it can be obtained by radical polymerization in the presence of a radical catalyst such as peroxide.

The amount of divinyl compound and monovinyl compound used is determined so as to give the composition of the polyfunctional vinyl copolymer used in the present invention. The divinyl compound is preferably used in an amount of 10 to 90 mol% of the total monomers, and more. It is preferably used in an amount of 30 to 90 mol%, more preferably 50 to 90 mol%. The monovinyl compound is preferably used in an amount of 90 to 10 mol%, more preferably 70 to 10 mol%, still more preferably 50 to 10 mol% of the total monomers. Here, in cationic polymerization such as 2-phenoxyethyl methacrylate, those acting as terminal modifiers are not calculated as monomers.

The Lewis acid catalyst used in the production of the polyfunctional vinyl copolymer is not particularly limited as long as it is a compound composed of a metal ion (acid) and a ligand (base) and can receive an electron pair. Can be used. From the viewpoints of control of molecular weight and molecular weight distribution and polymerization activity, boron trifluoride ether (diethyl ether, dimethyl ether, etc.) complexes are most preferably used. The Lewis acid catalyst is used in the range of 0.001 to 10 mol, more preferably 0.001 to 0.01 mol, relative to 1 mol of all monomers. An excessive amount of the Lewis acid catalyst is not preferable because the polymerization rate becomes too high and it becomes difficult to control the molecular weight distribution.

The cocatalyst includes one or more selected from ester compounds. Among them, ester compounds having 4 to 30 carbon atoms are preferably used from the viewpoint of controlling the polymerization rate and the molecular weight distribution of the copolymer. From the viewpoint of availability, ethyl acetate, propyl acetate and butyl acetate are preferably used. The cocatalyst is used in the range of 0.001 to 10 mol, more preferably 0.01 to 1 mol, relative to 1 mol of the monomer compound. When the amount of the cocatalyst used is excessive, the polymerization rate decreases and the yield of the copolymer decreases. On the other hand, when the amount of the cocatalyst used is too small, the selectivity of the polymerization reaction is lowered, the molecular weight distribution is increased, the gel is generated, and the polymerization reaction is difficult to control.

In addition, as a catalyst used for producing a polyfunctional vinyl copolymer by radical polymerization, monofunctional compounds such as azo compounds represented by azobisisobutyronitrile, dibenzoyl peroxide, t-butylperoxybenzoate, etc. Bifunctional or higher functional peroxides, such as functional peroxides and 1,1-bis (t-butylperoxy) cyclohexane, are exemplified, and may be used alone or in combination of two or more. Can do.

The polyfunctional vinyl copolymer used in the present invention can be obtained by the above production method, but it is necessary to leave a part of the vinyl group of the divinyl compound used as a monomer without polymerizing. . Then, on average, 2 or more, preferably 3 or more vinyl groups are present in one molecule. This vinyl group exists mainly as a structural unit represented by the above formula (a1). Then, by leaving a part of the vinyl group without being polymerized, the crosslinking reaction can be suppressed and solvent solubility can be imparted. Here, solvent-soluble means that it is soluble in toluene, xylene, THF, dichloroethane, or chloroform. Specifically, in 100 g of these solvents, 5 g or more dissolves at 25 ° C., and no gel is generated. Say. On the other hand, a part of the divinyl compound needs to be crosslinked or branched by the reaction of two vinyl groups, whereby a copolymer having a branched structure can be obtained. Thus, for some of the divinyl compounds, one of the two vinyl groups is reacted, one is left unpolymerized and the other is used in the present invention by reacting two vinyl groups. To obtain a polyfunctional vinyl copolymer. The polymerization method for obtaining such a polyfunctional vinyl copolymer is known as described above, and can be produced as described above.

The weight average molecular weight (Mw) of the polyfunctional vinyl copolymer is preferably 1,000 to 100,000, more preferably 5,000 to 70,000. If it is less than 1000, the effect of inhibiting the progress of gelation is reduced in continuous polymerization as in the case of using aromatic divinyl compounds and polyfunctional (meth) acrylates, and even in suspension polymerization, in the high conversion rate region. It is not preferable because it is difficult to control the molecular weight distribution and a sufficient effect cannot be obtained.

The unit containing a vinyl group derived from a divinyl compound introduced into the polyfunctional vinyl copolymer has a structural unit represented by the above formula (a1), and the molar fraction of the structural unit (a1) is 0.05. ~ 0.50. When the amount is less than 0.05 mol, it is not preferable because it is difficult to obtain a hyperbranched ultrahigh molecular weight copolymer. On the other hand, when the amount exceeds 0.50 mol, the molecular weight of the hyperbranched ultrahigh molecular weight copolymer is excessively increased, and gelation tends to occur, which is not preferable. In addition, as described above, those obtained by terminal modification with a compound having an unsaturated bond in the molecule include, in addition to the structural unit represented by the formula (a1), the terminal unsaturated bond-containing structural unit (a2) is also a vinyl group. Therefore, the total molar fraction (a3) of both is preferably 0.05 to 0.50.

The polyfunctional vinyl copolymer has a ratio of the radius of inertia (nm) in the weight average molecular weight to the molar fraction of the structural unit (a1) or the total molar fraction (a3) in the range of 1 to 100. It is preferable that it exists in. In order to prepare the branched ultrahigh molecular weight component for imparting strain hardening without gelation, the range of 10 to 80 is more preferable. When the above ratio exceeds 100, gelation does not proceed, but it is not preferable because it is difficult to obtain a hyperbranched ultrahigh molecular weight copolymer. On the other hand, a molecular weight smaller than 1 is not preferable because the molecular weight of the hyperbranched ultra-high molecular weight copolymer is excessively increased and gelation easily occurs. Here, the inertial radius is a value measured by the method described in the examples. The polyfunctional vinyl copolymer is a polymer having a distribution in molecular weight, and naturally, since the inertia radius also has a distribution, the inertia radius in the weight average molecular weight is adopted as the average value of the overall inertia radius. Is.

The ratio of the molar fraction of the structural unit (a1) or the total molar fraction (a3), which is an index representing the content of the double bond and the radius of inertia defined here, constitutes the branched ultrahigh molecular weight component. In this case, it can be said that it is an index that represents how many reaction points the polyfunctional vinyl copolymer serving as a nucleus has in the polymerization reaction solution. If this ratio is too small, the reaction point is in the vicinity and gelation is likely to occur, and if this ratio is too large, it is difficult to increase the molecular weight of the branched component.

The blending ratio of the polyfunctional vinyl copolymer relative to the styrene monomer is preferably 50 ppm to 5000 ppm, more preferably 100 ppm to 3000 ppm on a weight basis. When the blending ratio of the polyfunctional vinyl copolymer is less than 50 ppm, it is not preferable because sufficient effects of the present invention are hardly obtained. On the other hand, when it exceeds 5000 ppm, a gel may be produced.

By polymerizing the polyfunctional vinyl compound copolymer and a styrenic monomer, a hyperbranched ultra high molecular weight copolymer that is a copolymer of the polyfunctional vinyl copolymer and the styrenic monomer ( A styrenic resin composition of the present invention which is a mixture of a highly branched copolymer) and a linear polymer produced only from a styrenic monomer is obtained. When two or more types of monomers are used as the styrenic monomer, the linear polymer becomes a copolymer.

重量 The weight average molecular weight (Mw) of the styrene resin composition obtained by the present invention is preferably 200,000 to 800,000. If the Mw is less than 200,000, the impact strength after processing is insufficient, and if the Mw is greater than 800,000, the viscosity increases and the processability becomes insufficient.

The styrenic resin composition as described above contains a highly branched copolymer and a linear polymer. By using a styrenic resin composition exhibiting Mw as described above, a highly branched copolymer weight can be obtained. The coalescence has an ultra high molecular weight with Mw of 1 million or more, and the linear polymer has 100,000 to 500,000. The ratio of the hyperbranched ultrahigh molecular weight copolymer having an Mw of 1 million or more and the linear styrene polymer having an Mw of 100,000 to 500,000 is preferably 2:98 to 20:80. These ratios can be controlled by adjusting the blending ratio of the polyfunctional vinyl copolymer to the styrene monomer and the polymerization conditions.

製造 Regarding the production of the styrene resin composition, 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 such as an aliphatic mercaptan can be used as necessary.

The polymerization solvent is used to reduce the viscosity of the reaction product in continuous bulk polymerization, and the organic solvents include toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, anisole, cyanobenzene, dimethylformamide. N, N-dimethylacetamide, methyl ethyl ketone and the like.

In particular, in continuous bulk polymerization, when it is desired to increase the amount of polyfunctional vinyl copolymer added, it is preferable to use an organic solvent from the viewpoint of suppressing gelation. Thereby, the addition amount of the polyfunctional vinyl copolymer shown previously can be increased dramatically, and a gel is hardly generated.

The amount of the organic solvent used is not particularly limited, but it is usually 1 to 50 parts by weight with respect to 100 parts by weight of the total amount of the monomer components from the viewpoint of controlling gelation. Preferably, it is in the range of 5 to 30 parts by weight. When the amount exceeds 50 parts by weight, productivity is remarkably lowered, and the molecular weight of the chain styrene resin is excessively lowered, which is not preferable.

As the polymerization initiator, a radical polymerization initiator is preferable. For example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2- Peroxyketals such as bis (4,4-di-butylperoxycyclohexyl) propane, hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumylper Dialkyl peroxides such as oxide and di-t-hexyl peroxide, diacyl peroxides such as benzoyl peroxide and disinamoyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, t -Butylperoxy isopropyl monocarbon Peroxyesters such as N, N′-azobisisobutylnitrile, N, N′-azobis (cyclohexane-1-carbonitrile), N, N′-azobis (2-methylbutyronitrile), N , N′-azobis (2,4-dimethylvaleronitrile), N, N′-azobis [2- (hydroxymethyl) propionitrile], etc., and one or a combination of two or more of these may be used. be able to.

The chain transfer agent is added so that the molecular weight of the styrenic resin composition does not become excessively large. A monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer agents. Can be used. Examples of the monofunctional chain transfer agent include alkyl mercaptans and thioglycolic acid esters.

Polyfunctional chain transfer agents such as ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, etc. are esterified with thioglycolic acid or 3-mercaptopropionic acid. The thing which was done is mentioned.

Hereinafter, the present invention will be described more specifically with reference to examples. The measurement method used is as follows.

(GPC measurement method) High-performance liquid chromatography (HLC-8220GPC manufactured by Tosoh Corporation), RI detector, TSKgel GMHxl × 2, solvent THF, flow rate 1.0 ml / min. did.

(Double bond quantification method) The structural unit (a1), the double bond derived from the terminal denaturant (a2), and the total molar fraction of both (a3) were measured using a JNM-LA600 type nuclear magnetic resonance spectrometer manufactured by JEOL. The structure was determined by 13C-NMR and 1H-NMR analysis. Chloroform-d1 was used as a solvent, and the tetramethylsilane resonance line was used as an internal standard.

(Inertia radius) After adjusting the sample to a 0.5% THF solution, the sample was filtered with a membrane filter, and the filtrate was measured using a GPC multi-angle light scattering method. Further, the sample was adjusted to 0.2% THF solution and allowed to stand for 1 day. Thereafter, it was diluted to a solution having four kinds of concentrations (0.02, 0.05, 0.10, 0.12 wt%) using THF, and dn / dc measurement was performed using these solutions. The radius of inertia of the sample was calculated from the dn / dc value.

(Confirmation of gel-like material) A 180 mm × 180 mm × 3 mm flat plate was molded using an injection molding machine, and the presence or absence of linear traces from the gate portion generated when the gel-like material was contained was visually confirmed.

Synthesis example 1
(Polyfunctional vinyl copolymer α)
3.1 mol (399.4 g) of divinylbenzene, 0.7 mol (95.1 g) of ethylvinylbenzene, 0.3 mol (31.6 g) of styrene, 2.3 mol (463.5 g) of 2-phenoxyethyl methacrylate Then, 974.3 g of toluene was put into a 3.0 L reactor, 42.6 g of boron trifluoride diethyl ether complex was added at 50 ° C., and reacted for 6.5 hours. After stopping the polymerization reaction with a sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, and the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, dried and weighed to obtain 372.5 g of a polyfunctional vinyl copolymer. This polyfunctional vinyl copolymer α has a weight average molecular weight Mw of 8,000, a molar fraction of the structural unit (a1) containing a vinyl group derived from a divinyl compound is 0.44, and a two-phenoxyethyl methacrylate derived from the terminal 2-phenoxyethyl methacrylate. The double bond (a2) was 0.03, and the combined molar fraction (a3) of both was 0.47. The inertia radius (r) of the copolymer at a weight average molecular weight of 8,000 was 6.4 nm. It can be seen that the polyfunctional vinyl copolymer in this synthesis example has a branched structure as compared with the fact that the inertial radius at a linear molecular weight of 8000 is 15 nm. Further, the ratio (r / a3) between the radius of inertia (r) and the molar fraction (a3) is calculated as 13.6.

Synthesis example 2
(Polyfunctional vinyl copolymer β)
2.6 mol (332.0 g) of divinylbenzene, 1.5 mol (198.0 g) of ethyl vinylbenzene, 1.1 mol (109.6 g) of styrene, 3.1 mol (630.4 g) of 2-phenoxyethyl methacrylate Then, 886.0 g of toluene was put into a 3.0 L reactor, 35.5 g of boron trifluoride diethyl ether complex was added at 50 ° C., and reacted for 5.0 hours. After stopping the polymerization reaction with a sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, and the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, dried, and weighed to obtain polyfunctional vinyl copolymer β564.0 g. The Mw of this polyfunctional vinyl copolymer β is 5000, the molar fraction of the structural unit (a1) containing a vinyl group derived from a divinyl compound is 0.25, and the double bond derived from the terminal 2-phenoxyethyl methacrylate ( a2) was 0.02, and the combined molar fraction (a3) of both was 0.27. Further, the inertia radius of the copolymer in terms of the weight average molecular weight was 8.1 nm. It can be seen that the polyfunctional vinyl copolymer in this synthesis example has a branched structure as compared with the fact that the radius of inertia at a linear molecular weight of 5000 is 12 nm.

Synthesis example 3
(Polyfunctional vinyl copolymer γ)
1.2 mol (159.8 g) of divinylbenzene, 0.7 mol (95.3 g) of ethylvinylbenzene, 2.1 mol (223.2 g) of styrene, 3.1 mol (632.0 g) of 2-phenoxyethyl methacrylate Then, 1082.5 g of toluene was put into a 3.0 L reactor, 56.8 g of boron trifluoride diethyl ether complex was added at 50 ° C., and reacted for 6.0 hours. After stopping the polymerization reaction with a sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, and the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, dried and weighed to obtain 340.8 g of a polyfunctional vinyl copolymer γ. The Mw of this polyfunctional vinyl copolymer γ is 5000, the mole fraction of the structural unit (a1) containing a vinyl group derived from a divinyl aromatic compound is 0.13, and the double fraction derived from the terminal 2-phenoxyethyl methacrylate The bond (a2) was 0.01, and the total molar fraction (a3) of both was 0.14. Further, the inertia radius of the copolymer in the weight average molecular weight was 10.6 nm. It can be seen that the polyfunctional vinyl copolymer in this synthesis example has a branched structure as compared with the fact that the radius of inertia at a linear molecular weight of 5000 is 12 nm.
All the polyfunctional vinyl copolymers in Synthesis Examples 1 to 3 were soluble in toluene, xylene, THF, dichloroethane, and chloroform.

Example 1
It has two tank reactors with a total mixing capacity of 30 L connected in series, a tower reactor of 15 L with a built-in static mixer with plug flow, a preheater, and a vacuum tank In a continuous bulk polymerization equipment having a flash chamber type devolatilization equipment, 85 parts by weight of styrene, 15 parts by weight of ethylbenzene and 0.06 part by weight of a polyfunctional vinyl copolymer (α) are uniformly mixed and then continuously at 15 L / hr. Sent in. The temperature of the first reactor is 130 ° C., the second reactor is 140 ° C., the third reactor is heated to 140 ° C. at the inlet and 160 ° C. at the outlet, and then the temperature is increased to 220 ° C. Transfer to a preheater heated to ℃ and put it in a vacuum tank directly under the preheater whose pressure is adjusted to 8 Torr to remove unreacted monomers and solvent, and then use a gear pump to remove the resin from the vacuum tank into a strand. The styrenic resin composition was obtained by cutting while extracting. Table 1 shows the results of evaluating the molecular weight and the gel-like substance for the resin composition 24 hours, 72 hours, and 144 hours after reaching the steady state while maintaining this steady state.

Example 2
A polystyrene resin composition was obtained in the same manner as in Example 1 except that the polyfunctional vinyl copolymer (β) was used instead of the polyfunctional vinyl copolymer (α) in Example 1. Table 1 shows the molecular weight at each time and the evaluation results of the gel-like material.

Example 3
A polystyrene resin composition was obtained in the same manner as in Example 1 except that the polyfunctional vinyl copolymer (γ) was used instead of the polyfunctional vinyl copolymer (α) in Example 1. Table 1 shows the molecular weight at each time and the evaluation results of the gel-like material.

Example 4
A polystyrene resin composition was obtained in the same manner as in Example 1, except that 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 1 was changed to 0.01 part by weight. Table 1 shows the molecular weight at each time and the evaluation results of the gel-like material.

Example 5
Except that 70 parts by weight of styrene and 30 parts by weight of ethylbenzene were used, and 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 1 was changed to 0.3 part by weight. A polystyrene resin composition was obtained. Table 1 shows the molecular weight at each time and the evaluation results of the gel-like material.

Example 6
Except for adding 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 1 to 0.1 part by weight and adding 0.05 part by weight of t-dodecyl mercaptan (tDM) together with styrene. A polystyrene resin composition was obtained in the same manner as in Example 1.

Comparative Example 1
A linear polystyrene was obtained in the same manner as in Example 1 except that the polyfunctional vinyl copolymer (α) was not added.

Comparative Example 2
A polystyrene resin composition was obtained in the same manner as in Example 1 except that the addition amount of 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 1 was changed to 0.001 part by weight.

Comparative Example 3
A polystyrene resin composition was obtained in the same manner as in Example 1 except that the addition amount of the polyfunctional vinyl copolymer (α) in Example 1 was changed to 1 part by weight.

Comparative Example 4
A polystyrene resin composition was obtained in the same manner as in Example 1 except that 0.05 part by weight of divinylbenzene was used instead of the polyfunctional vinyl copolymer (α) in Example 1. Table 1 shows the molecular weight at each time and the evaluation results of the gel-like material. No gel-like material was observed at 24 hours, but a gel-like material was generated at 72 hours, and a large amount of gel-like material was contained at 144 hours.

Comparative Example 5
A polystyrene resin composition was obtained in the same manner as in Example 1 except that 0.025 part by weight of divinylbenzene was used instead of the polyfunctional vinyl copolymer (α) in Example 1. No gel-like substance was observed at 72 hours, but generation of a gel-like substance was confirmed at 144 hours.

Comparative Example 6
Except that 0.05 parts by weight of divinylbenzene was used instead of the polyfunctional vinyl copolymer (α) in Example 1, the ratio of styrene to the solvent ethylbenzene was 70 parts by weight of styrene and 30 parts by weight of ethylbenzene. A polystyrene resin composition was obtained in the same manner as in Example 1.

Table 1 shows the amounts of reaction raw materials used and physical properties of the polystyrene resin compositions in Examples 1 to 6 and Comparative Examples 1 to 6.

Example 7
A jacket having an internal volume of 10 liters, 3 kg of a styrene monomer in which 0.06 parts by weight of a polyfunctional vinyl copolymer (α) is uniformly mixed in a reactor equipped with a stirrer, and 0.05 parts by weight of calcium triphosphate as a suspension stabilizer Then, 4 kg of water containing 0.005 part by weight of sodium dodecylbenzenesulfonate as a surfactant was charged, and the solution was suspended under stirring. 0.2 parts by weight of tertiary butyl peroxybenzoate as a polymerization initiator and 0.04 parts by weight of α-methylstyrene dimer as a chain transfer agent were added to 100 parts by weight of styrene monomer. The suspension was polymerized by heating at 115 ° C. for 5 hours and at 140 ° C. for 3 hours with stirring. After completion of the polymerization, hydrochloric acid was added to the suspension to neutralize the tribasic calcium phosphate that is a suspension stabilizer. The obtained bead-shaped resin was washed and filtered, and then dried with hot air to obtain a styrene resin composition.

Example 8
A styrene resin composition was obtained in the same manner as in Example 7, except that the polyfunctional vinyl copolymer (β) was used instead of the polyfunctional vinyl copolymer (α) in Example 7.

Example 9
A styrene resin composition was obtained in the same manner as in Example 7, except that the polyfunctional vinyl copolymer (γ) was used instead of the polyfunctional vinyl copolymer (α) in Example 7.

Example 10
A polystyrene resin composition was obtained in the same manner as in Example 7, except that 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 7 was changed to 0.01 part by weight.

Example 11
A polystyrene resin composition was obtained in the same manner as in Example 7, except that 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 7 was changed to 0.1 part by weight.

Comparative Example 7
A linear polystyrene was obtained in the same manner as in Example 7 except that the polyfunctional vinyl copolymer (α) was not added.

Comparative Example 8
A polystyrene resin composition was obtained in the same manner as in Example 7, except that 0.06 part by weight of the polyfunctional vinyl copolymer (α) in Example 7 was changed to 0.001 part by weight.

Comparative Example 9
A polystyrene resin composition was obtained in the same manner as in Example 7, except that the addition amount of the polyfunctional vinyl copolymer (α) in Example 7 was changed to 1 part by weight.

Comparative Example 10
A polystyrene resin composition was obtained in the same manner as in Example 7, except that 0.05 part by weight of divinylbenzene was used instead of the polyfunctional vinyl copolymer (α) in Example 7.

Table 2 summarizes the amounts used of the reaction raw materials and the physical properties of the polystyrene resin composition in Examples 7 to 11 and Comparative Examples 7 to 10.

In Tables 1 and 2, the crosslinking agent means a polyfunctional vinyl copolymer or divinylbenzene (DVB), and the chain transfer agent means tDM. The total Mw means the weight average molecular weight of the polystyrene resin composition, the ratio of Mw 1,000,000 or more means the ratio (wt%) in the polystyrene resin composition, and Y in the evaluation of the gel-like substance indicates that there is a gel-like substance. Meaning N means none.

Industrial applicability

According to the present invention, in processing accompanied by thin-wall stretching represented by foam molding, it does not contain a microgel that induces breakage of the thin-walled portion, and has excellent melting characteristics represented by strain-hardening properties and uniform meat during stretching. A styrenic resin composition containing a hyperbranched ultrahigh molecular weight copolymer and a linear polymer that can be thickened can be produced. Furthermore, by using the styrenic resin composition obtained by the present invention, sagging at the time of secondary processing, thickness unevenness, tearing due to a gel-like material, and deterioration of appearance are suppressed. In addition, various problems such as drawdown during blow molding, bubble breakage during foam molding, bubble enlargement, and continuous cell generation can be solved.

Claims

A method for producing a styrene-based resin composition containing a hyperbranched ultrahigh molecular weight copolymer and a linear polymer, wherein a monovinyl compound essentially comprising styrene has a vinyl group in one molecule. The solvent-soluble polyfunctional vinyl copolymer having two or more and having a branched structure is added at 50 ppm to 5000 ppm on a weight basis to proceed the polymerization reaction, and the solvent-soluble polyfunctional vinyl copolymer and the monovinyl compound are copolymerized. A styrenic resin composition comprising a hyperbranched ultrahigh molecular weight copolymer produced as a result and a linear polymer produced by polymerization of the monovinyl compound.
A solvent-soluble polyfunctional vinyl copolymer is obtained by polymerizing a divinyl compound and a monovinyl compound copolymerizable with the divinyl compound, and further contains a pendant vinyl group-containing unit derived from the divinyl compound represented by the following formula (a1) in the structural unit. The molar fraction is contained in the range of 0.05 to 0.50, and the ratio of the inertial radius (nm) in the weight average molecular weight to the molar fraction is in the range of 1 to 100. Item 2. A method for producing a styrene-based resin composition according to Item 1.

(In the formula, R 1 represents a hydrocarbon group derived from a divinyl compound.)
A claim 1 or 2 styrenic resin composition obtained by the method described, and the weight average molecular weight of the high branched ultra-high molecular weight copolymer 2.0 ~ 20.0 wt% of 1,000,000 or more, weight average molecular weight A styrenic resin composition comprising 100,000 to 500,000 linear styrenic polymer of 80.0 to 98.0 wt% and having a weight average molecular weight of 200,000 to 800,000.