JP6917173B2 - Rubber-modified styrene resin composition, sheet, molded product, manufacturing method - Google Patents

Description

The present invention relates to a rubber-modified styrene-based resin composition, a sheet made of the rubber-modified styrene-based resin composition, a molded product made of the sheet, and a method for producing the rubber-modified styrene-based resin composition.

Since the rubber-modified styrene resin sheet has an excellent balance between impact resistance and molding processability and is inexpensive, various types of food trays, lunch containers, cups, etc. can be obtained by thermoforming such as vacuum forming and vacuum forming. It is processed into a molded product. Recently, in these fields, there is a strong tendency for molded products to become thinner and larger, and there is an increasing need for molded products having a higher deep drawing ratio than before. Conventional rubber-modified styrene resin sheets have problems such as tearing of the sheet during deep drawing molding and uneven thickness of the molded product, and there is a demand for a material that is more uniformly stretched during secondary molding. In addition, there is an increasing demand for materials with better appearance.

In improving the secondary moldability of a sheet, in order for the resin to have a more uniform wall thickness in the process of melting and stretching, a material with an appropriate balance of viscosity and elasticity, in other words, viscoelasticity and flow. A material with an excellent balance of sex is required. Viscoelasticity can be measured with a die well.

As a means for improving viscoelasticity, it is known that a method of containing a high molecular weight component in a styrene resin is effective.

As a method of introducing a high molecular weight component into an impact-resistant styrene resin composition to improve moldability with less gel-like substance, for example, Patent Document 1 describes a multi-branched polystyrene obtained by using a multi-branched macromonomer. And an impact-resistant styrene-based resin composition containing linear polystyrene in the matrix phase are disclosed. Although the improvement of bending energy and the formability are disclosed, there is no description about the stretchability at the time of secondary molding. Further, Patent Document 2 discloses an impact-resistant styrene resin composition containing a highly branched ultra-high molecular weight copolymer produced by polymerizing a solvent-soluble polyfunctional vinyl copolymer having a branched structure and a monovinyl compound. ing. Although the improvement of the uneven thickness and strength of the container during secondary molding is disclosed, there is room for improvement in reducing gel-like substances because the number of pendant vinyl groups in the solvent-soluble polyvinyl chloride copolymer is 2 or more. be.

Japanese Unexamined Patent Publication No. 2007-269884 Japanese Unexamined Patent Publication No. 2016-222751

The present invention is a rubber-modified styrene resin composition containing a branched high molecular weight component, which has an excellent balance between die well and fluidity and has a small amount of gel-like substance, and has excellent stretchability during secondary molding. The present invention is to provide a sheet and a molded product made of the sheet.

As a result of diligent research to achieve the above object, the present inventors have formed a matrix phase of a rubber-modified styrene resin composition with a predetermined conjugated divinyl compound and a predetermined monovinyl compound in an appropriate content ratio. At the same time, by controlling the molecular weight, molecular weight distribution, and high molecular weight ratio of the matrix phase within an appropriate range, a molded product having excellent drawability during secondary molding and having a good appearance can be obtained. It was found that this was possible, and the present invention was completed.

That is, the present invention is as shown below.

[1] A rubber-modified styrene resin composition comprising rubber-like polymer particles containing a rubber-like polymer containing a styrene-based polymer and a matrix phase.
(A) The matrix phase contains a styrene-based copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 1000 to 100,000 and a monovinyl compound containing at least a styrene-based compound.
(B) The ratio of the conjugated divinyl compound is 3.3 × 10 ^{-6 to} 2.0 × 10 ^-4 mol with respect to 1 mol of the total amount of the monovinyl compound.
(C) The matrix phase has a weight average molecular weight (Mw) of 130,000 to 400,000.
(D) The rubber-modified styrene resin composition, wherein the matrix phase has a proportion of components having a molecular weight of 1 million or more of 1.0 to 6.0%.
[2] The rubber-modified styrene resin composition according to [1], wherein the content of the rubber-like polymer particles is in the range of 5 to 40% by mass.
[3] The rubber-modified styrene resin composition according to [1] or [2], wherein the ratio Mz / Mw of the Z average molecular weight (Mz) to Mw in the matrix phase is 1.8 to 5.0.
[4] The rubber-modified styrene resin composition according to any one of [1] to [3], wherein the conjugated divinyl compound has a number average molecular weight (Mn) of 2000 to 30000.
[5] The rubber-modified styrene resin composition according to any one of [1] to [4], wherein the conjugated divinyl compound is in the form of a chain.
[6] The rubber-modified styrene resin composition according to any one of [1] to [5], wherein the conjugated vinyl group of the conjugated divinyl compound is located at the terminal.
[7] The rubber-modified styrene resin composition according to any one of [1] to [6], wherein the conjugated divinyl compound is a hydrogenated or non-hydrogenated polybutadiene di (meth) acrylate.
[8] The melt mass flow rate measured under the conditions of 200 ° C. and 49 N load was 1.0 to 8.0 g / 10 minutes, and the die was measured by a melt indexer at a load of 98 N and a resin extrusion speed of 10 g / 10 minutes. The rubber-modified styrene resin composition according to any one of [1] to [7], wherein the well is 35% or more.
[9] A sheet made of the rubber-modified styrene resin composition according to any one of [1] to [8], and a molded product made of the sheet.
[10] The method for producing a rubber-modified styrene resin composition according to any one of [1] to [9], which comprises using continuous solution polymerization or continuous bulk polymerization.

According to the present invention, a rubber-modified styrene resin composition containing a branched high molecular weight component, which has an excellent balance between die well and fluidity and has a small amount of gel-like substance, and has excellent stretchability during secondary molding. A sheet thereof and a molded product made of the sheet can be obtained.

(A) is a partial schematic view of a melt indexer used for the die-well measurement of the rubber-modified styrene resin composition according to the embodiment of the present invention. (B) is a partially enlarged view showing the circled portion indicated by the alternate long and short dash line in (A).

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description, and various modifications are made within the scope of the gist thereof. Can be carried out.

<Rubber-modified styrene resin composition>
The rubber-modified styrene-based resin composition in the present embodiment is a rubber-modified styrene-based resin composition composed of rubber-like polymer particles containing a rubber-like polymer containing a styrene-based polymer and a matrix phase.
(A) The matrix phase contains a styrene-based copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 1000 to 100,000 and a monovinyl compound containing at least a styrene-based compound.
(B) The ratio of the conjugated divinyl compound is 3.3 × 10 ^{-6 to} 2.0 × 10 ^-4 mol with respect to 1 mol of the total amount of the monovinyl compound.
(C) The matrix phase has a weight average molecular weight (Mw) of 130,000 to 400,000.
(D) The matrix phase is characterized in that the proportion of components having a molecular weight of 1 million or more is 1.0 to 6.0%.
In the rubber-modified styrene resin composition of the present embodiment, the matrix phase is composed of a predetermined conjugated divinyl compound and a predetermined monovinyl compound in an appropriate content ratio, and the molecular weight of the matrix phase is appropriate as described above. By controlling the range, it is possible to obtain a rubber-modified styrene resin composition having excellent molding processability and a small amount of gel-like substance.
Specifically, although not limited to the theory, in the present embodiment, the styrene-based copolymer obtained by polymerization is cross-linked with two molecular chains mainly composed of a monovinyl compound and the conjugates of these molecular chains. It can be easily formed with a divinyl compound, and the distance between the two molecular chains at that time can be set to a predetermined distance (the molecular chain of the styrene-based copolymer is formed into an "H" shape. I guess it's easy). By forming the styrene-based copolymer in this way, the molecular chains of the styrene-based copolymer can be easily entangled with each other effectively (such an effect is also referred to as "entanglement effect"). Therefore, the moldability of the rubber-modified styrene resin composition can be improved.
At the same time, in the present embodiment, the content of the conjugated divinyl compound and the molecular weight and molecular weight distribution of the matrix phase are within a predetermined range, so that the molding processability of the rubber-modified styrene resin composition is effectively improved. At the same time, it is possible to effectively prevent the rubber-modified styrene resin composition from forming a gel. Therefore, according to the present embodiment, it is possible to obtain a rubber-modified styrene resin composition having excellent molding processability and a small amount of gel-like substance.

<Matrix phase>
The matrix phase of the rubber-modified styrene resin composition of the present embodiment contains a styrene copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 1000 to 100,000 and a monovinyl compound containing at least a styrene compound.

In the rubber-modified styrene resin composition of the present embodiment, the weight average molecular weight (Mw) of the matrix phase from which the rubber-like polymer particles have been removed is 130,000 to 400,000, preferably 160,000 to 380,000, more preferably 18. It is 10,000 to 350,000. The ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) is 1.8 to 5.0, preferably 2.0 to 4.5, and more preferably 2.2 to 4. It is 0.0. By setting the Mw of the matrix phase to 130,000 to 400,000 and the Mz / Mw to the range of 1.8 to 5.0, the generation of gel-like substances can be generated while ensuring the strength of the rubber-modified styrene resin composition. It can be suppressed to further improve molding processability and fluidity.
In the rubber-modified styrene resin composition of the present embodiment, the weight average molecular weight (Mw) and Z average molecular weight (Mz) of the above-mentioned weight average molecular weight (Mw) are the same as those of the conjugated divinyl compound when the rubber-modified styrene resin composition is radically polymerized. It can be controlled by the type and addition amount, reaction temperature, residence time, type and addition amount of polymerization initiator, type and amount of solvent, type and addition amount of chain transfer agent, and the like.

The proportion of the components having a molecular weight of 1 million or more in the matrix phase in the present embodiment is 1.0 to 6.0%, preferably 1.5 to 6.0%, and more preferably 2.0 to 5.5%. .. By setting the proportion of the component having a molecular weight of 1 million or more in the range of 1.0 to 6.0%, a rubber-modified styrene resin composition having excellent secondary moldability with a balance between die well and fluidity can be obtained. The content of the gel-like substance can be very low.
In the rubber-modified styrene resin composition of the present embodiment, the above molecular weight ratios are the type and addition amount of the conjugated divinyl compound, the reaction temperature, the residence time, and the polymerization when the styrene monomer is radically polymerized. It can be controlled by the type and amount of the initiator, the type and amount of the solvent, the type and the amount of the chain transfer agent, and the like.
Here, in the present disclosure, the weight average molecular weight (Mw), Z average molecular weight (Mz), and the proportions of components having a molecular weight of 1 million or more in the matrix phase are measured using gel permeation chromatography (GPC). The value.

<< Conjugated divinyl compound >>
The conjugated divinyl compound in the present embodiment is a compound having a number average molecular weight (Mn) of 1000 to 100,000 and having at least two conjugated vinyl groups in the molecule. Further, the conjugated divinyl compound in the present embodiment is preferably in the form of a chain rather than in the form of a network, 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. The side chain preferably has 6 or less carbon atoms, and more preferably 4 or less carbon atoms.
Further, the conjugated vinyl group in the conjugated divinyl compound can be at any position in the molecule, but at least two of the two conjugated vinyl groups are located at different ends in the molecule. It is preferable to have. When the conjugated divinyl compound is in the form of a chain, it is more preferable that the two conjugated vinyl groups are located at different ends of the main chain (that is, both ends of the main chain become conjugated divinyl groups). It is more preferable to have it). The polymerization reactivity can be enhanced by locating the conjugated vinyl group at the terminal.
Further, when the conjugated divinyl compound is chain-like and three or more conjugated vinyl groups are present, it is preferable that two of the three or more conjugated vinyl groups are located at the terminals. More preferably, the remaining one or more conjugated vinyl groups are also terminally located.
If the number of conjugated vinyl groups in the conjugated divinyl compound is large, the number of branching points increases, and gelation may easily occur in the process of recovering the reactor and raw materials, resulting in deterioration of the transparency of the styrene copolymer. In addition, since it is necessary to clean the reactor and the productivity may decrease, the number is preferably 5 or less, more preferably 4 or less, and further preferably 3 or less. From the same viewpoint, it is particularly preferable that the conjugated divinyl compound has two conjugated vinyl groups.
Here, the "terminal" can be the position at the most end of the molecular chain, but if the conjugated vinyl group is present near the end, it has effective reactivity with the monovinyl compound and suppresses gelation. Therefore, in the present embodiment, the "terminal" may be a portion (end portion) in the molecular chain including the position (atom) at the most end of the molecular chain (in other words, the end portion). For example, the conjugated vinyl group can be located near the end). The portion within the certain range is not limited, but is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less of the stretched chain length of the conjugated divinyl compound. 5% or less is even more preferable.

In the present embodiment, the conjugated vinyl group includes an olefinic double bond copolymerizable with a monovinyl compound and a structure (for example, a carbonyl group, an aryl group, etc.) that forms a conjugated system with the olefinic double bond. It is a group having. 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, for example, ( Examples thereof include a structure in which meta) acrylate, urethane (meth) acrylate, aromatic vinyl, maleic acid, fumaric acid and the like are added. The at least two conjugated vinyl groups may be the same or different from each other.

The number average molecular weight (Mn) of the conjugate divinyl compound of the present embodiment is 1000 to 100,000, preferably 1,500 to 80,000, more preferably 2,000 to 60,000, and even more preferably 2,000 to 30,000. When the number average molecular weight (Mn) is less than 1000, the distance between the conjugated vinyl groups of the conjugated divinyl compound is short, so that the distance between the polymer chains bonded to the conjugated divinyl compound is short, and a sufficient entanglement effect cannot be obtained. , Inferior in molding processability. When the molecular weight exceeds 100,000, the distance between the conjugated vinyl groups of the conjugated divinyl compound becomes long, and the reactivity of the conjugated vinyl group at the terminal decreases (because the molecular weight of the conjugated divinyl compound is large, the conjugated vinyl group at the terminal reacts. This is not preferable because the amount of high-molecular-weight components produced is reduced.
The number average molecular weight (Mn) of the conjugated divinyl compound means a polystyrene-equivalent number average molecular weight (Mn) 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, and polyphenylene sulfide. Specific conjugated divinyl compounds include (hydrogenated) polybutadiene-terminated (meth) acrylate (“(hydrogenated)” refers to a hydrogenated or non-hydrogenated compound; the same shall apply hereinafter), polyethylene. Terminal di (meth) acrylate compounds such as glycol-terminated (meth) acrylate, polypropylene glycol-terminated (meth) acrylate, ethoxylated bisphenol A-terminal (meth) acrylate, and ethoxylated bisphenol F-terminal (meth) acrylate, and (hydrogenated). Examples thereof include terminal urethane acrylate compounds such as polybutadiene terminal urethane acrylate, polyethylene glycol terminal urethane acrylate, polypropylene glycol terminal urethane acrylate, ethoxylated bisphenol A terminal urethane acrylate, and ethoxylated bisphenol F terminal urethane acrylate. For example, in the case of polypropylene glycol-terminated (meth) acrylate, the number of bonds of propylene glycol in the repeating unit is determined so that the number average molecular weight (Mn) is 1000 to 100,000. From the viewpoint of compatibility with the styrene-based copolymer, the conjugated divinyl compound is preferably (hydrous) polybutadiene-terminated (meth) acrylate, polystyrene-terminated (meth) acrylate, or polyphenylene ether-terminated divinyl. In addition, "terminal" and "both ends" in the compound name mean that the conjugated vinyl group is located at both ends.

The content of the conjugate divinyl compound of the present embodiment is 3.3 × 10 ^{-6 to} 2.0 × 10 ^-4 mol, preferably 5.0 × 10 ^-6 to 1. It is 5 × 10 ^-4 mol, more preferably 8.0 × 10 ^{-6 to} 1.2 × 10 ^-4 mol. If the content is ^{less than 3.3 × 10 -6} mol, the moldability is inferior. On the other hand, when the content exceeds 2.0 × 10 ^-4 mol, a large amount of gel-like substance is generated and the appearance becomes poor. Further, the proportion of the high molecular weight resin increases, the viscoelasticity is too strong, the elongation at the time of melting the resin decreases, and the moldability deteriorates.
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 1} H-NMR and ^{13 C-NMR.}

<< Monovinyl compound >>
The rubber-modified styrene-based resin composition of the present embodiment contains at least one type of monovinyl compound containing at least a styrene-based compound (as a monomer forming the rubber-modified styrene-based resin composition), and the monovinyl compound is , It may be composed of only a styrene-based compound (monomer), or may be composed of a compound having another monovinyl group capable of copolymerizing with the styrene-based compound together with the styrene-based compound. The monovinyl compound is not particularly limited as long as it can be copolymerized with the styrene compound as well as the styrene compound. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and cetyl (meth). Examples include vinyl compounds such as acrylate and (meth) acrylonitrile, and dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleic anhydride, maleimide, and nuclear-substituted maleimide. Examples of the styrene-based compound include styrene, α-methylstyrene, paramethylstyrene, ethylstyrene, propylstyrene, butylstyrene, chlorostyrene, bromostyrene and the like, and styrene is preferable.
The content of the monovinyl compound constituting the matrix phase is 60 to 95% by mass, preferably 65 to 90% by mass, based on the mass of the rubber-modified styrene resin composition.

<Rubber-like polymer particles>
The rubber-like polymer particles of the rubber-modified styrene-based resin composition of the present embodiment contain the styrene-based polymer inside the rubber-like polymer and graft-polymerize the styrene-based monomer on the outside. .. The rubbery polymer particles are dispersed in the matrix phase in the resin.

<< Rubbery polymer >>
As the rubber-like polymer, polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used, but 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. Further, as the structure of the styrene-butadiene copolymer, both a random structure and a block structure can be used. One or more of these rubbery polymers can be used. Further, saturated rubber obtained by hydrogenating butadiene rubber can also be used.
The content of the rubber-like polymer is 1 to 20% by mass, preferably 2 to 15% by mass, based on the mass of the rubber-modified styrene resin composition.
In the present disclosure, the content of the rubbery polymer is a value measured by the procedure described in the section [Example] described later.

The content of the rubber-like polymer particles in the rubber-modified styrene-based resin composition is 5 to 40% by mass, preferably 10 to 35% by mass, based on 100% by mass of the rubber-modified styrene-based resin composition. By setting the content of the rubber-like polymer particles in the range of 5 to 40% by mass, an excellent balance between rigidity and impact resistance can be obtained. When the content of the rubber-like polymer particles exceeds 40% by mass, the solution viscosity of the polymerization system becomes high when the rubber-modified styrene resin composition is produced, and the operation tends to be difficult. Here, the content of the rubber-like polymer particles can be measured as the content of the toluene-insoluble content in the rubber-modified styrene resin composition.
The swelling index of the rubber-like polymer particles is preferably 7 to 14, more preferably 8 to 13. If the swelling index is in the range of 7 to 14, the mechanical strength is excellent. The swelling index of the rubber-like polymer particles can be measured as the swelling index of the toluene insoluble matter in the rubber-modified styrene resin composition.
In the present disclosure, the toluene insoluble content and the swelling index are values measured by the procedure described in the section of [Example] described later.

The melt mass flow rate (MFR) of the rubber-modified styrene resin composition of the present embodiment is 1.0 to 8.0 g / 10 minutes, preferably 1.2 to 7.0 g / 10 minutes, and more preferably 1.2. ~ 5.0 g / 10 minutes.
In the present disclosure, the melt mass flow rate is a value measured at 200 ° C. and a load of 49 N in accordance with ISO1133.

The die well measured with a melt indexer under a load of 98 N and a resin extrusion rate of 10 g / 10 minutes is preferably 35% or more, more preferably 45% or more, and even more preferably 50% or more.
In the present disclosure, the die well is a value measured by the procedure described in the section [Example] described later.

When the melt mass flow rate is 1.0 to 8.0 g / 10 minutes and the die well is 35% or more, the balance between the fluidity and viscoelasticity of the resin is excellent, and the secondary formability such as deep drawing is very excellent. .. Further, it is preferable that drawdown does not occur during sheet extrusion.

The rubber particle size of the rubber-like polymer particles is preferably 0.7 to 5.0 μm, more preferably 0.9 to 4.5 μm, and even more preferably 1.1 to 4.0 μm. By setting the range from 0.7 to 5.0 μm, a product having excellent rigidity, mechanical strength and gloss can be obtained. The rubber particle size is the region (phase transition) in which the rubber-like dispersed particles are formed in the polymerization step, and the number of revolutions of the stirrer of the reactor, the molecular weight of the rubber-like polymer used, the 1,2-vinyl bond content, and the initiator. It can be adjusted by the type and amount of addition, the type and amount of chain transfer agent, and the like.
In the present disclosure, the rubber particle size is a value measured from a transmission electron micrograph by the ultrathin section method.

The raw material solution contains a monovinyl compound containing a styrene compound, a rubbery polymer, and a conjugated divinyl compound. The conjugated divinyl compound, which is a component of the rubber-modified styrene resin composition of the present embodiment, can be added from the middle of the above reactor as needed in a state of being dissolved in monovinyl compounds, a polymerization solvent and the like. ..

Further, from the viewpoint of controlling the polymerization reaction, a polymerization initiator, a polymerization initiator such as an organic peroxide, or a chain transfer agent can be used, if necessary. The polymerization solvent is used for adjusting the polymerization rate, molecular weight, etc. in continuous bulk polymerization or continuous solution polymerization. The solvent is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and dialkyl ketones such as methyl ethyl ketone, which may be used alone or in combination of two or more. May be good. Further, other solvents such as aliphatic hydrocarbons can be mixed with aromatic hydrocarbons as long as the solubility of the polymerization product is not lowered. These solvents are preferably used in a range not exceeding 25% by weight with respect to the monomer. When the amount of the solvent exceeds 25% by weight, the polymerization rate is remarkably lowered, and the impact strength of the obtained resin is significantly lowered. In addition, a large amount of energy is required to recover the solvent, which is inferior in economic efficiency. The solvent may be added after the polymerization has progressed and the viscosity has become relatively high, or it may be added before the polymerization, but it should be added at a ratio of 5 to 20% by weight before the polymerization. It is preferable that the quality is easily made uniform and the polymerization temperature is controlled.

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. As a result, the amount of the conjugated divinyl compound added can be increased, and gel is less likely to be formed.

The polymerization initiator is not particularly limited, but is an organic peroxide, for example, 2,2-bis (t-butylperoxy) butane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4, Peroxyketals such as 4-bis (t-butylperoxy) valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide, and diacyl peroxides such as acetyl peroxide and isobutylyl peroxide. , Peroxydicarbonates such as diisopropylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, hydroperoxides such as t-butylhydroperoxide and the like. It is preferable to add 0.005 to 0.08% by mass with respect to the styrene-based monomer.

Examples of the chain transfer agent include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, 1-phenyl-2-fluorene, dibenzene, chloroform and other mercaptans, terpenes, halogen compounds, telepinolene and the like. And so on. The amount of this chain transfer agent used is not particularly limited, but it is generally preferable to add about 0.005 to 0.3% by weight based on the monomer.

The rubber-modified styrene-based resin composition of the present embodiment can be obtained by adding a conjugated divinyl compound to a styrene-based compound in which a rubber-like polymer is dissolved and continuously polymerizing it. Additives such as prepolymerized styrene resin and liquid paraffin can be melt-blended by an extruder or dry-blended in a pellet state.

Examples of the above-mentioned styrene-based resin and additives include rubber-reinforced aromatic vinyl-based resins such as GP-PS resin for improving fluidity and MBS resin containing rubber for improving strength, and aromatics such as SBS. Examples include vinyl-based thermoplastic elastomers. Examples of the additive include higher fatty acids such as stearic acid, zinc stearate, calcium stearate and magnesium stearate, salts thereof, lubricants such as ethylene bisstearylamide, and antioxidants.

<Manufacturing method of rubber-modified styrene resin composition>
As an example of the method for producing the rubber-modified styrene resin composition of the present embodiment, a monovinyl compound containing a styrene compound in which a rubber-like polymer is dissolved and a conjugated divinyl compound, a polymerization solvent, a polymerization catalyst, and chain transfer, if necessary, are used. The monomers are continuously sent to one or more reactors arranged in series and / or in parallel and a facility equipped with a volatile matter removing step of removing unreacted monomers and the like by adding and mixing agents and the like. A so-called continuous lumpy polymerization method is preferably used, in which the polymer is added and the polymerization is carried out stepwise. Examples of the reactor type include a completely mixed type, a laminar flow type, and a loop type reactor in which a part of the polymerization solution is extracted while advancing the polymerization. The order of arrangement of these reactors is not particularly limited, but a laminar flow reactor is preferably used. In the devolatilization step, a vacuum devolatilization tank equipped with a heater, a devolatilization extruder, or the like is generally used. For example, a vacuum devolatilization tank with a heater is used in only one stage, a vacuum devastation tank with a heater is connected in two stages in series, or a vacuum devastation tank with a heater and a devolatilization extruder are used. In order to reduce the volatile content as much as possible, a vacuum devastation tank with a heater is connected in two stages, or a vacuum devastation tank with a heater is used. It is preferable that the devolatilization extruder is connected in series.
Alternatively, a styrene-based monomer obtained by copolymerizing the above-mentioned conjugated divinyl compound with one or more types of monovinyl compounds including at least a styrene-based compound, and a styrene-based monomer in the presence of a rubber-like polymer. And the conventional rubber-modified styrene resin (HIPS) which does not contain the above-mentioned conjugated divinyl compound obtained by optionally polymerizing an additional monomer, is known from a single-screw extruder, a twin-screw extruder, a Banbury mixer and the like. It can also be obtained by a method of melt-kneading using the kneader of the above.

<Sheet>
The rubber-modified styrene resin composition of the present embodiment can be molded in various ways by known molding methods such as extrusion molding and injection molding, but is suitable for extrusion molding, and is suitable for T-die sheet extruder and biaxial stretching. It can be molded into a sheet or film by using an apparatus or an inflation processing apparatus. In the case of a sheet, it may be a single layer or may be used as a part of a multi-layer sheet. The thickness of the sheet varies depending on the use in the molded product and is not particularly limited, but is usually 0.2 to 3.0 mm. Similarly, the film is not particularly limited, but is usually 10 to 200 μm.

<Molding>
The sheet made of the rubber-modified styrene resin composition of the present embodiment can be secondarily formed into various shapes by thermoforming such as vacuum forming or vacuum forming, and can be used for various packaging containers. Specific examples of the molded product using the sheet include a food tray, a lunch container, a cup, a dessert container, an ice cream container, a frozen dessert container, a yogurt container, a milk portion, a side dish container, a tofu container and the like.

Examples and comparative examples carried out for confirming the effect of the present invention will be shown below, and the present invention will be described in more detail. In the following description, specific compound names, numerical values, and the like are given, but the present invention is not limited to these examples. The analysis method and the resin evaluation method used in the present invention will be described.

(1) Measurement of Molecular Weight The number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), and molecular weight of the styrene-based copolymers obtained in Examples and Comparative Examples described later are 1 million or more. The proportions of the components were measured using gel permeation chromatography (GPC) under the following conditions.
Equipment: Tosoh HLC-8220
Sorting column: Tosoh TSK gel Super HZM-H
Guard column: Tosoh TSK guard volume Super HZ-H
Measuring solvent: tetrahydrofuran (THF)
Sample concentration: Dissolve 5 mg of the measurement sample in 10 mL of solvent Injection amount: 10 μL
Measurement temperature: 40 ° C
Flow velocity: 0.35 mL / min To create a calibration curve, 11 types of TSK standard polystyrene manufactured by Tosoh Co., Ltd. (F-850, F-450, F-128, F-80, F-40, F-20, F-10) , F-4, F-2, F-1, A-5000). A calibration curve was created using an approximate expression of a linear straight line.

(2) Measurement of the number of moles of the conjugated divinyl compound contained in 1 mol of styrene The number of moles of the conjugated divinyl compound contained in 1 mol of styrene was measured using JOEL-ECA500 manufactured by JEOL Ltd.

(3) Measurement of Melt Mass Flow Rate (MFR) The melt mass flow rate (g / 10 minutes) of the rubber-modified styrene resin composition obtained in Examples and Comparative Examples described later was measured at 200 ° C. in accordance with ISO1133. , 49N under load conditions.

(4) Measurement of Die Well The die well (%) of the rubber-modified styrene resin composition obtained in Examples and Comparative Examples described later was measured using a melt indexer T101 manufactured by Toyo Seiki Seisakusho Co., Ltd. did. As shown in FIGS. 1 (A) and 1 (B), the temperature of the molten resin (rubber-modified styrene resin composition) is adjusted in the heater section, and the weight is 98 N from the orifice having a diameter of 2 mm (D1). The extrusion speed was set to 10 g / 10 minutes. The diameter (D2) at a position about 3 mm from the tip of the extruded rod-shaped resin strand was measured, and the die well was determined by the following formula.
Dicewell = (D1-D2) / D2 × 100

(5) Measurement of Toluene Insoluble Content and Swelling Index The toluene insoluble content (mass%) and swelling index in the rubber-modified styrene resin composition were measured as follows. Weigh 1.00 g of rubber-modified styrene resin composition into a settling tube (this mass is W1), add 20 ml of toluene, shake at 23 ° C for 2 hours, and then centrifuge (Sakuma Seisakusho Co., Ltd., SS). Centrifugation was carried out at a temperature of 4 ° C., a rotation speed of 20000 rpm, and a centrifugal acceleration of 45100 × G for 60 minutes at −2050A rotor: 6B-N6L). The sedimentation tube was slowly tilted to about 45 degrees and the supernatant was decanted and removed. The mass of the insoluble matter containing toluene is precisely weighed (this mass is referred to as W2), subsequently vacuum-dried at 160 ° C. and 3 kPa or less for 1 hour, cooled to room temperature in a desiccator, and then the mass of the toluene insoluble matter. Was precisely weighed (this mass is W3).
The content and swelling index of toluene insoluble matter in the rubber-modified styrene resin composition, that is, the content and swelling index of the rubber-like polymer particles in the rubber-modified styrene resin composition were determined by the following formulas.
Toluene insoluble content = W3 / W1 × 100
Toluene insoluble swelling index = W2 / W3

(6) Measurement of Rubber-like Polymer Content The rubber-like polymer content (mass%) in the rubber-modified styrene resin composition was measured as follows. 0.4 g of the rubber-modified styrene resin composition was precisely weighed in a volumetric flask (this mass is W), 75 mL of chloroform was added and dispersed well, and then 18 g of iodine monochloride was dissolved in 1000 mL of carbon tetrachloride. 20 mL of the solution was added, stored in a cool and dark place, and after 8 hours, chloroform was added and aligned with the marked line. 25 mL of this was collected, 60 mL of a solution of 10 g of potassium iodide dissolved in 800 mL of water and 200 mL of ethanol was added, and 10 g of sodium thiosulfate was dissolved in 1000 mL of water (the molar concentration of this solution is x). Titrated with. The main test AmL and the blank test BmL were used, and the content (mass%) of the rubbery polymer was calculated by the following formula.
Rubber polymer content = 10.8 × xx (BA) / W

(7) Measurement of rubber particle size To measure the rubber particle size (μm) of the rubber-like polymer particles, take a transmission electron micrograph by the ultrathin section method and measure the particle size of 1000 particles in the photograph. It was calculated by the following formula.
Rubber particle size = Σni ・ Di ⁴ / Σni ・ Di ³
(In the formula, ni is the number of rubber particles having a particle size Di. Di is the average value of the major axis and the minor axis of the particles.)

(8) Measurement of Charpy Impact Strength The rubber-modified styrene resin composition obtained in Examples and Comparative Examples described later was used in an injection molding machine (EC60N, manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 230 ° C. and a mold temperature. Molding was performed at 45 ° C., an injection pressure of 80 MPa, and an injection speed of 26 mm / s to obtain an ISO mold type A test piece. The Charpy impact strength (kJ / m ² ) of the obtained test piece was measured with a notch in accordance with ISO179.

(9) Measurement of tensile yield strength With respect to the test piece obtained in (8) above, the tensile yield strength (MPa) was measured in accordance with ISO527.

(10) Stretch Moldability of Sheet Using a compression molding machine manufactured by Soken Co., Ltd., a compression molding sheet having a thickness of 1.2 mm, a length of 80 mm and a width of 80 mm was prepared at 200 ° C., and then a biaxial shaft manufactured by Toyo Seiki Seisakusho Co., Ltd. Using the stretching machine EX6-S1, 10 sheets were preheated at 120 ° C. for 10 minutes and then stretched three times at a speed of 100 mm / min at the same time in both vertical and horizontal directions. The quality of the sex was judged.
The number of broken sheets was 0, which was "◎ (excellent)", 1 to 3 was "○ (good)", and 4 to 10 was "x (defective)".

(11) Measurement of deep drawing property of sheet A sheet having a thickness of 0.3 mm was prepared using a 30 mmφ sheet extruder manufactured by Soken Co., Ltd. Then, using a sheet container molding machine manufactured by Soken Co., Ltd., the sheet was sandwiched between the fixed frames of the container molding machine, and heated at an average heater temperature of 200 ° C., an atmospheric temperature of 130 ° C., and a heating time of 60 seconds. Next, vacuum forming was performed by sliding the fixed frame together with a cup-shaped mold (temperature 40 ° C.) having a diameter of 8 cm and a height of 10 cm, and 20 molded bodies were molded for each Example and Comparative Example. The deep drawing property of the sheet was judged from the number of containers in which the shape of the mold was accurately transferred to the molding container.
The number of containers accurately transferred to the molding container is 18 to 20 as "◎ (excellent)", 15 to 17 as "○ (good)", and 0 to 14 as "x". (Defective) ".

(12) Measurement of Appearance of Molded Product With respect to the 20 containers obtained in (11), the presence or absence of a gel-like substance having an average of 1 mm or more in minor axis and major axis was observed, and the appearance quality of the molded article was judged.
The number of containers containing the gel-like substance was 0 to 2 as "◎ (excellent)", 3 to 7 as "○ (good)", and 8 or more as "x (poor)".

The conjugated divinyl compounds 3 and 4 used in Examples and Comparative Examples described later were produced based on the following methods.
Production example: Conjugated divinyl compound 3 (polybutadiene terminal acrylate, number average molecular weight: 2300)
In a 5 L reaction vessel equipped with a stirrer, a thermometer and a reflux condenser, 2742 g of polybutadiene double-ended alcohol (Mn: 2200), 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-tetramethylpiperidin-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 water content of this mixture was measured by the Karl Fischer method, and it was confirmed that the water content was 200 ppm or less. Then, as a transesterification catalyst, 1.3685 g of tetra n-butyl titanate was added to the mixture, and the produced methanol was distilled off from the reaction system under reflux of n-hexane, which is an azeotropic solvent, while stirring. The reaction was carried out at a reaction temperature of 80 to 85 ° C. for 10 hours.

Next, the temperature inside the reaction vessel was adjusted to 75 to 80 ° C., and the mixture was concentrated at a reduced pressure of 70 to 2 kPa until 95% or more of the methyl acrylate and n-hexane used were distilled off to remove excess methyl acrylate. n-Hexane was recovered. To the resulting polybutadiene both ends diacrylate 2070 g, toluene 2000 g, acetone 200 g, hydrotalcite (formula _{Mg 6 Al 2 (OH) 16} CO 3 · 4H 2 O) [manufactured by Kyowa Chemical as ion-exchange water 20g and transesterification catalyst 20 g of [Kyoward 500PL] manufactured by Kogyo Co., Ltd. was added, and the mixture was treated at 75 to 80 ° C. for 2 hours. Next, the temperature inside the reaction vessel was adjusted to 75 to 80 ° C., and the mixture was concentrated at a reduced pressure of 90 to 35 kPa to recover 400 g of a mixed distillate of toluene, acetone and water, and the obtained concentrated solution was air-conditioned. The catalyst and the adsorbent were separated by filtration under pressure, and the solvent was further devolatile at a temperature of 60 to 80 ° C. at a reduced pressure of 30 to 0.8 kPa to obtain a conjugated divinyl compound 3.

When the conversion rate of the polybutadiene double-ended diacrylate of the conjugated divinyl compound 3 was measured by high performance liquid chromatography (HPLC), it was 99.3%, and the molecular weight was 2300 in terms of polystyrene.

Production example: Conjugated divinyl compound 4 (polybutadiene terminal acrylate, number average molecular weight: 26000)
The conjugated divinyl compound 4 was produced under the same conditions as the conjugated divinyl compound 3 except that the type of the polybutadiene two-terminal alcohol was changed. The conjugated divinyl compound 4 had a number average molecular weight (Mn) of 26000, and the conversion rate of the polybutadiene biterminal diacrylate was measured and found to be 99.5%.

<Example 1>
83 parts by mass of styrene monomer, 9 parts by mass of ethylbenzene, 0.08 parts by mass of conjugated divinyl compound 1 [manufactured by Osaka Organic Chemical Industry Co., Ltd .: BAC-45 (Mn: 4800)] (2.09 per mol of styrene) × 10 ^-5 mol), 7 parts by mass of polybutadiene [Asahi Kasei Co., Ltd .: Diene 55], and 1,1-bis (t-butylperoxy) cyclohexane [Nichiyu Co., Ltd .: Perhexa C] as the polymerization initiator 1. The raw material solution was prepared by adding 011 parts by mass and 0.050 parts by mass of α-methylstyrene linear dimer [Nofmer MSD manufactured by Oil & Fat Products Co., Ltd.] as the chain transfer agent 1. The prepared raw material solution is continuously supplied at 3 L / hour to a 6.2 L laminar flow reactor-1 equipped with a stirrer and whose temperature can be controlled in 3 zones, and the temperature is adjusted to 126 ° C./131 ° C./136 ° C. It was adjusted. The rotation speed of the stirrer was 30 rpm. The reaction rate at the reactor outlet was 33%. 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 reactor-1 and having temperature control in 3 zones. The rotation speed of the stirrer was 15 rpm, and the temperature was 135 ° C./140 ° C./145 ° 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 reactor-2 and having temperature control in 3 zones. The rotation speed of the stirrer was 10 rpm, and the temperature was 155 ° C./160 ° C./165 ° C. Subsequently, the reaction solution from the laminar flow reactor-3 is supplied to an extruder with a two-stage vacuum vent adjusted to 240 ° 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.
Table 1 shows the production conditions and analysis results of the rubber-modified styrene resin composition.

Examples 2 to 5 and Comparative Examples 1 to 4 were synthesized in the same manner as in Example 1 except that the conditions were changed as shown in Table 1, and the styrene copolymers Mw, Mz, Mz / Mw, The proportions of the components having a molecular weight of 1 million or more were controlled as shown in Table 1.

In Example 2 and Comparative Examples 1, 3 and 4, n-dodecyl mercaptan was added as a chain transfer agent 2 from the inlet of the laminar flow reactor-2 to the reaction solution at the concentration shown in Table 1.
Further, in Examples 2, 4 and 5, and Comparative Examples 1 to 4, liquid paraffin was added to the raw material solution in the amount shown in Table 1.

The following commercially available conjugated divinyl compounds, polymerization initiators, liquid paraffins, and chain transfer agents listed in Table 1 were used.
Conjugated divinyl compound 1: Polybutadiene terminal acrylate [Osaka Organic Chemical Industry Co., Ltd .: BAC-45] Mn: 4800
Conjugated divinyl compound 2: Urethane acrylate oligomer [manufactured by Tomoe Kogyo Co., Ltd .: CN9014NS] Mn: 8000
Conjugated divinyl compound 5: 1,3-butylenediol methacrylate [manufactured by Wako Pure Chemical Industries, Ltd.] Molecular weight: 226
Conjugated divinyl compound 6: NK ester A-GLY-20E [manufactured by Shin-Nakamura Chemical Industry Co., Ltd.] Molecular weight: 1295, the average number of conjugated vinyl in one molecule of conjugated divinyl compound 6 is 3.
Polymerization Initiator 1: 1,1-Bis (t-Butyl Peroxy) Cyclohexane [manufactured by NOF CORPORATION]
Polymerization initiator 2: Di-t-butyl peroxide [manufactured by NOF CORPORATION]
Liquid paraffin: PS-350S [manufactured by Sanko Chemical Co., Ltd.]
Chain transfer agent 1: α-methylstyrene dimer [NOF: NOFMER MSD]
Chain transfer agent 2: n-dodecyl mercaptan [manufactured by Wako Pure Chemical Industries, Ltd.]

As is clear from Table 1, in Comparative Example 1 in which the number of moles of the conjugated divinyl compound contained in 1 mol of the monovinyl compound was ^{as small as 1.43 × 10 -6} mol, the Mz / Mw ratio was small and the die well was also small. The next workability was inferior. In Comparative Example 2, in which the number of moles of the conjugated divinyl compound contained in 1 mol of the monovinyl compound was as large as 2.68 × 10 ^-4 mol, gelation in the reactor was severe during polymerization, and a sample could not be obtained. In Comparative Example 3 in which the number average molecular weight Mn of the conjugated divinyl compound was as small as 226, the anchoring effect was thin and the secondary moldability was inferior because the distance between the branched polymers was short. In Comparative Example 4, the average number of vinyls in the conjugated divinyl compound was 3, the amount of gel-like substance was large, and the appearance of the sheet was inferior.

On the other hand, it is a styrene-based copolymer of a conjugated divinyl compound having a number average molecular weight (Mn) of 1000 to 100,000 and one or more types of monovinyl compounds including at least a styrene-based compound, and contains rubber-like polymer particles. The amount (content of toluene insoluble matter in Table 1) is in the range of 5 to 40% by mass, and the ratio of the conjugated divinyl compound is 3.3 × 10 ^-6 to 2 with respect to 1 mol of the total amount of the monovinyl compound. It is 0.0 × 10 ^-4 mol, and the styrene-based copolymer has a weight average molecular weight (Mw) of 130,000 to 400,000, and the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) (Mz). / Mw) is 1.8 to 5.0, and the proportion of components having a molecular weight of 1 million or more in the styrene-based copolymer is 1.0% to 6.0%, Examples 1 to 5 It can be seen that the rubber-modified styrene-based resin composition of No. 1 is excellent in molding processability, particularly secondary moldability, and also has a small amount of gel-like substance on the sheet, so that the appearance of the molded product is excellent.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and can be appropriately changed without departing from the spirit of the invention.

By using the rubber-modified styrene resin composition according to the present invention, the molding processability is excellent and the amount of gel-like substance is small, and the molding material for home appliances, office machine products, miscellaneous goods, housing equipment, etc., food packaging material, etc. Can be widely used as.

Claims (12)

A rubber-modified styrene-based resin composition comprising rubber-like polymer particles containing a rubber-like polymer containing a styrene-based polymer and a matrix phase.
(A) The matrix phase contains a styrene copolymer of a chain conjugated divinyl compound having a number average molecular weight (Mn) of 1000 to 100,000 and a monovinyl compound containing at least a styrene compound, and the conjugated divinyl compound is It has an olefinic double bond copolymerizable with the monovinyl compound, a structure forming a conjugated system with the olefinic double bond, and a main chain structure of polybutadiene, hydrogenated polybutadiene or polyisoprene.
(B) The ratio of the conjugated divinyl compound is 3.3 × 10 ^{-6 to} 2.0 × 10 ^-4 mol with respect to 1 mol of the total amount of the monovinyl compound.
(C) The matrix phase has a weight average molecular weight (Mw) of 130,000 to 400,000.
(D) The rubber-modified styrene resin composition, wherein the matrix phase has a proportion of components having a molecular weight of 1 million or more of 1.0 to 6.0%. The rubber-modified styrene resin composition according to claim 1, wherein the content of the rubber-like polymer particles is in the range of 5 to 40% by mass. The rubber-modified styrene resin composition according to claim 1 or 2, wherein the ratio Mz / Mw of the Z average molecular weight (Mz) to Mw in the matrix phase is 1.8 to 5.0. The rubber-modified styrene resin composition according to any one of claims 1 to 3, wherein the conjugated divinyl compound has a number average molecular weight (Mn) of 2000 to 30,000. The rubber modification according to any one of claims 1 to 4, wherein the conjugated divinyl compound has an aryl group substituted with an acryloyl group or a vinyl group and a main chain structure of polybutadiene, hydrogenated polybutadiene or polyisoprene. Styrene-based resin composition. The conjugate divinyl compound according to any one of claims 1 to 5, wherein the conjugated divinyl compound has a structure in which (meth) acrylate, urethane (meth) acrylate, aromatic vinyl, maleic acid or fumaric acid is added to the main chain structure. Rubber-modified styrene resin composition. The rubber-modified styrene resin composition according to any one of claims 1 to 6 , wherein the conjugated vinyl group of the conjugated divinyl compound is located at the terminal. The rubber-modified styrene resin composition according to any one of claims 1 to 7 , wherein the conjugated divinyl compound is a hydrogenated or non-hydrogenated polybutadiene di (meth) acrylate. The melt mass flow rate measured under the conditions of 200 ° C. and 49 N load was 1.0 to 8.0 g / 10 minutes, and the die well measured by the melt indexer at a load of 98 N and a resin extrusion speed of 10 g / 10 minutes was 35. % Or more, the rubber-modified styrene resin composition according to any one of claims 1 to 8. A sheet comprising the rubber-modified styrene resin composition according to any one of claims 1 to 9. A molded product comprising the sheet according to claim 10. The method for producing a rubber-modified styrene resin composition according to any one of claims 1 to 11 , wherein continuous solution polymerization or continuous bulk polymerization is used.

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