JPH03227326A - Styrene based resin sheet - Google Patents

Abstract

PURPOSE:To obtain the title sheet for meat tray having excellent balance of gloss, stiffness and impact resistance by blending a rubber-modified styrene based resin having occlusion structure as dispersed rubber state with general-purpose polystyrene and molding the blend. CONSTITUTION:The aimed sheet obtained by molding (A) a rubber-modified styrene based resin having occulusion structure as dispersed rubber state or blend consisting of >=20wt.% of the component A and (B) <=80wt.% general-purpose polystyrene. Furthermore, it is desirable to use the above-mentioned sheet as the outer layer and use a polyolefin resin or a rubber-modified styrene based resin sheet having salami structure as the inner layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a novel styrenic resin sheet, more specifically, it has an excellent balance of gloss, rigidity, and impact resistance, and has almost no decrease in gloss during thermoforming. A specific rubber-modified styrenic resin single-layer sheet, a styrenic resin laminate sheet of a thermoplastic resin sheet and a specific rubber-modified styrenic resin sheet, and a styrenic resin foam sheet and a specific rubber sheet, which have excellent characteristics such as This invention relates to a styrene resin foam laminated sheet with a modified styrenic resin film.

[Conventional technology] Styrene resin sheets have been widely used as materials for parts of home appliances and OA equipment, and styrene resin foam sheets are lightweight and have excellent heat insulation and cushioning properties. Therefore, it is widely used in the field of packaging and cushioning materials, especially in food packaging containers and packaging trays. However, conventional styrene resins have had the disadvantage that it is difficult to obtain sheets or foam sheets with an excellent balance of gloss, rigidity, and impact resistance.

By the way, in order to improve the impact resistance of styrenic resins, styrene can be added to the rubbery polymer by blending a rubbery polymer with polystyrene or by polymerizing styrene in the presence of the rubbery polymer. is partially graft-polymerized, and the remainder of the styrene becomes polystyrene,
Industrially, a rubber-like polymer/styrene graft copolymer and polystyrene are mixed together, a so-called rubber-modified polystyrene resin, and sheets are produced from the mixture.

In such rubber-modified polystyrene resins, the rubbery polymer is usually dispersed in the form of particles in the styrene polymer, and the size of these particles has a close relationship with impact resistance and gloss. is well known. That is, the smaller the particles of the rubbery polymer, the better the gloss, but on the other hand, the impact resistance decreases in proportion to the smaller the particles of the rubbery polymer, and below a certain limit, the impact resistance decreases. ,
The effect of improving impact resistance is virtually eliminated.

In conventional rubber-modified polystyrene resins, in order to obtain the desired impact resistance, the rubber-like polymer is mixed with a particle size of 1/7 m.
As mentioned above, although the particles are usually dispersed in the polystyrene resin phase in the range of 1 to 10 pm, there is a problem in that they are inferior in gloss and rigidity and are therefore subject to limitations in use.

In order to solve this problem, the rubber particles are dispersed in a single occlusion structure (called a shell/core structure) with an average particle diameter of about 0.1 to 0.7 μm, which improves gloss and impact resistance. It is known that good rubber-modified styrenic resins can be obtained (West German Patent Publication No. 3.345,377, JP-A-63-112646, JP-A-1-261444). however,
Although such rubber-modified styrenic resins have improved gloss, they have drawbacks such as insufficient impact resistance, especially falling weight impact strength, and a decrease in gloss when the sheet is thermoformed.

[Problems to be Solved by the Invention] Under these circumstances, the present invention provides a styrene resin sheet with improved gloss and impact resistance, or an aged resin sheet with an excellent balance of gloss, rigidity, and impact resistance. The object of this invention is to provide a styrenic resin sheet that suppresses a decrease in gloss even when the sheet is heated, and a foamed styrenic resin sheet that is lightweight and has good heat insulation properties.

[Means for Solving the Problems] The present inventors have conducted repeated research on f-at) to develop rubber-modified styrenic resins that are excellent in gloss and impact resistance, particularly in falling weight impact strength. By specifying the structure, we discovered a rubber-modified styrenic resin with an occlusion structure that has excellent gloss and impact resistance, especially falling weight impact strength.

As a result of further intensive research, the present inventors found that a single-layer sheet is made of a rubber-modified styrenic resin having this occlusion structure, or a mixture of a predetermined ratio of the rubber-modified styrene resin and general-purpose polystyrene as a base resin. has an excellent balance of gloss, rigidity, and impact resistance, and there is almost no decrease in surface gloss even in the aged form, and a laminated sheet with the above-mentioned base resin as an outer layer and a thermoplastic resin sheet as an inner layer has excellent gloss and resistance. It has excellent impact resistance, and on the surface of the styrenic resin foam, a rubber-modified styrene-based resin having an occlusion structure, or a styrene made of a mixture of the rubber-modified styrene-based resin and general-purpose polystyrene in a predetermined ratio. It was discovered that a sheet made by laminating resin films has the characteristics of the single-layer sheet described above, is lightweight, and has good heat insulation properties, and based on this knowledge, the present invention was completed.

That is, the present invention provides a rubber-modified styrene-based resin in which the dispersed rubber form has an occlusion structure, or a rubber-modified styrene-based resin of 20% by weight or more and general-purpose polystyrene 8.
A styrenic resin sheet (Sheet E) formed by molding a mixture of 0% by weight or less, a styrenic resin sheet (Sheet Il) formed by laminating this sheet as an outer layer and a thermoplastic resin sheet as an inner layer, and (A) ) Surface i of general-purpose polystyrene and/or rubber-modified styrenic resin foam sheet
: , (B) A styrenic resin with a thickness of 5 to 100 μm, consisting of a rubber-modified styrenic resin alone or a mixture of 20% by weight or more of this rubber-modified styrene-based resin and 80% by weight or less of general-purpose polystyrene, whose dispersed rubber form has an occlusion structure. A styrenic resin sheet (sheet m) formed by laminating resin films is provided.

The present invention will be explained in detail below.

The occlusion structure in the rubber-modified styrenic resin in which the dispersed rubber form used in the styrenic resin sheets I, II, and ■ of the present invention has an occlusion structure means that in one rubber particle, the core is a styrene polymer, refers to a structure in which 5 or less occlusions made of a rubber-like polymer are included, and at least 50% of the occlusions are il.

The rubber-modified styrenic resin must have a dispersed rubber form of 70% or more of the above-mentioned occlusion structure, and if 30% or more of particles such as salami structure are mixed,
There is a possibility that good gloss cannot be obtained. Therefore, in the present invention, high-impact polystyrene (H
IPS) can also be blended in a proportion of less than 30% in terms of the number of rubber particles.

Among the rubber-modified styrenic resins, the rubber-modified styrene-based resin has an occlusion structure with a plane of symmetry and has an area average particle diameter of 0.1-0.
．． 7 pm, preferably 0.2-0.6 μm, and the ratio of area average particle size to number average particle size is in the range of 1.0 to 2.5, preferably 1.0 to 1.8. Dispersed in styrene resin is suitable. When the area average particle diameter is less than 0.1 μm, impact resistance is insufficient, and when it exceeds 0.7 μm, gloss tends to decrease. Furthermore, when the ratio of the area average particle diameter to the number average particle diameter exceeds 2.5, the gloss tends to decrease. Furthermore, when the dispersed particles of the rubbery polymer have an occlusion structure with a plane of symmetry, even better impact resistance can be obtained.

Furthermore, for the rubber-modified styrenic resin, the volume fraction of the rubber-like polymer particles (CIR), the area average particle diameter (diameter) of the rubber-like polymer particles (Di, and the thickness of the rubber-like polymer phase (
=〆, (1-[((D,/2)-λ)/(D S
/2)]"l-'... (I) (t: λ is 0.10 μm or less) is 0.18 or more, preferably 0.20 or more, more preferably 0.22 It is preferable that the value is less than 0.18.If the value is less than 0.18, the falling weight impact strength is insufficient.

The volume fraction (U,) of the rubbery polymer particles is expressed by the formula %formula%) () It can be found by

Here, ρ is the specific gravity of the rubbery polymer, and 0.90 is used. In addition, Pps is the specific gravity of the styrene polymer, and is 1
．． 05 is used. Furthermore, Wll is the weight fraction of the rubbery polymer contained in the rubber-modified styrenic resin, expressed by the formula %] () Area average particle diameter (diameter) of the rubbery polymer particles (D, ) and (D,) can be found as follows. Specifically, pellets of a rubber-modified styrenic resin with a small degree of orientation were treated with a 3% by weight osmium tetroxide aqueous solution, and then sliced into thin sections using an ultramicrotome. A transmission electron microscope image of this pellet was obtained, and the rubber-like appearance in the image was obtained. By measuring the diameter (CD) of the polymer particles in the major axis direction of 1000 particles and finding the area average value according to the following formula,
The area average particle size (diameter) (Ds) and (D, ) of the rubbery polymer particles are obtained.

(n is the number of rubbery polymer particles in diameter) The thickness (λ) of the rubbery polymer phase is determined by obtaining a transmission electron microscope image in the same manner as described above. Among the rubbery polymer particles, Thickness λi of the rubbery polymer phase of rubbery polymer particles in which the rubbery polymer phase exists only at the periphery, i.e., the rubbery polymer particles are cut near the center.
is obtained by measuring 100 particles and calculating the number average value according to the following formula.

λ=(λ1+λ, +λ, +...10λ1°.)/
100 In addition, a transmission electron microscope image was similarly obtained, and the ratio of the number of occlusion structure particles to 1000 randomly extracted particles was determined to evaluate the ratio of occlusion structure particles.

In the comb-modified styrenic resin, the rubber polymer particles preferably have a specific microstructure. That is, it is desirable that the amount of gel is in the range of 1.1 to 4.0 weight ratio, preferably 1.4 to 3.6 weight ratio to the rubbery polymer, and the swelling index is 5 to 20, Preferably 7
It is desirable that it be in the range of ~18. The amount of gel is 1.1
If the weight ratio is less than 4.0, the impact resistance will not be sufficient, and if the weight ratio exceeds 4.0, the gloss may deteriorate. Furthermore, if the swelling index deviates from the above range, the impact strength tends to decrease.

In the rubber-modified styrenic resin, the styrenic polymer and the rubbery polymer are 70 to 92% by weight and 3% by weight, respectively.
0-8% by weight, preferably 72-90% and 28-8% by weight
The content is preferably 10% by weight. If the content of the rubbery polymer is less than 8% by weight, the effect of improving impact resistance will not be sufficiently exhibited, and if it exceeds 30% by weight, gloss and fluidity will tend to decrease.

Further, in the rubber-modified styrenic resin, the thickness (λ) of the gono-like polymer phase is preferably 0.10 μm or less. The thickness (λ) of the rubbery polymer phase is 0.10 μm
In order to achieve the above, it is necessary to increase the molecular weight of the rubber-like polymer used (for example, when using a styrene-butane diene block copolymer rubber, the molecular weight of the butane diene polymer block portion must be approximately goo, ooo or higher).

When a rubber-modified styrenic resin is produced using such a high molecular weight rubbery polymer, the viscosity of the polymerization reaction solution increases significantly, which is undesirable. Thickness of the rubbery polymer phase (λ
) is preferably o, oos to 0.07 μm.

The rubber-modified styrenic resin can be prepared by polymerizing styrene or a monomer copolymerizable with styrene in the presence of a rubbery polymer. Examples of monomers copolymerizable with styrene include aromatic monovinyl monomers such as α-methylstyrene, vinyltoluene, vinylethylbenzene, vinylxylene, pt-butylstyrene, σ-methyl-p-methylstyrene, and vinylnaphthalene. Examples include compounds such as acrylonitrile, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, maleic anhydride, and phenylmaleimide. These monomers may be used alone or in combination of two or more types, but they usually account for 50% by weight or less, preferably 40% by weight or less, based on the total monomers containing styrene. Used in percentages.

On the other hand, there are no particular restrictions on the type of rubber-like polymer;
Conventional rubber-modified styrene resins, such as natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, and styrene-based
Synthetic rubbers such as isoprene copolymer rubber, butyl rubber, ethylene-propylene copolymer rubber, or graft copolymer rubbers of these rubbers and styrene can be used, but among these, styrene-butadiene Block copolymer rubbers are preferred. This styrene-butadiene block copolymer rubber has a molecular weight in the range of so, o o to soo, ooo, and has a content of polymer blocks formed from styrenes of 10 to 60% by weight. Particularly preferred are those within this range.

If the molecular weight is less than 50,000, the impact resistance will not be sufficient, and if it exceeds soo or ooo, the fluidity during molding will decrease, which is not preferable. Further, this styrene-butadiene block copolymer rubber has a molecular weight of 50,000 to soo, oo.

A certain amount of polybutadiene rubber may be appropriately blended and used.

There are no particular restrictions on the polymerization method, and conventionally used methods such as emulsion polymerization, bulk polymerization, solution polymerization,
A suspension polymerization method or a multistage polymerization method such as a bulk to suspension two-stage polymerization method can be used.

Next, to explain one example of a suitable method for producing a rubber-modified styrenic resin using a bulk-suspension two-stage polymerization method, first, a rubber-like polymer is added to a mixture of styrene or a monomer copolymerizable with styrene. Add and heat as necessary to dissolve. It is preferable to perform this dissolution as uniformly as possible.

Next, a molecular weight regulator (chain transfer agent) such as an alkyl mercaptan and a polymerization initiator such as an organic peroxide to be used as necessary are added to this solution, and while heating to a temperature of about 70 to 150°C, , the degree of polymerization is 10-60 under stirring.
% by bulk polymerization method. In this prepolymerization step, the rubbery polymer is dispersed into particles by stirring.

Next, the prepolymerization solution is suspended in an aqueous phase using tricalcium phosphate, polyvinyl alcohol, or the like as a suspending agent,
Usually, suspension polymerization (main polymerization) is carried out until the degree of polymerization approaches 100%. Note that, if necessary, heating may be continued after this main polymerization step.

Examples of the molecular weight regulator include α-methylstyrene dimer, mercaptans such as n-dodecylmercaptan, t-dodecylmercaptan, 1-phenylbutene-2-fluorene, dipentene, and chloroform, terpenes, and halogen compounds. can.

In addition, examples of the polymerization initiator used as desired include 1.1-bis(t-butylperoxy)cyclohexane, 1.1-bis(t-butylperoxy)-3,3
, peroxyketals such as 5-trimethylcyclohexane, dialkyl peroxides such as dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane,
Diaryl peroxides such as penzoyl peroquinde and m-toluoyl peroxide, peroxydicarbonates such as dimyristylperoxydicarbonate, peroxyesters such as t-butylperoxyisopropylcarbonate, cyclohexanone peroxide, etc. Examples include organic peroxides such as ketone peroxides, hydroperoxides such as p-menthane hydroperoxide, and the like.

The thickness λ of the rubbery polymer phase can be controlled by changing the molecular weight of the butadiene polymer block when, for example, a styrene-butadiene block copolymer rubber is used as the rubbery polymer. . That is, if the molecular weight of the butadiene polymer block portion is decreased, λ will be decreased, and if it is increased, λ will be increased. On the other hand, the radius R of the rubbery polymer particles depends on the stirring speed during polymerization, the molecular weight of the styrene polymer block when a styrene-butadiene block copolymer rubber is used as the rubbery polymer, and the use of a chain transfer agent. It can be controlled by the presence or absence of polybutadiene rubber blended with the styrene-butadiene block copolymer rubber. That is, when the stirring speed during polymerization is fast, R decreases, and when it is slow, R increases.

When the molecular weight of the styrene polymer block portion is increased, R decreases, and when it is decreased, R increases. Further, R is small when a chain transfer agent is not used, but increases when a chain transfer agent is used, and R is increased when a polybutadiene rubber is used, but R is small when not used.

Next, the slurry obtained in this way is separated by conventional means to remove the bead-shaped reactants, dried, and then pelletized according to a conventional method to obtain the desired rubber-modified styrenic resin. can get. The molecular weight of the matrix portion of the rubber-modified styrenic resin thus obtained is 100,000 to 300,000, preferably 13
Advantageously, it lies in the range 0.000 to 280,000. If the molecular weight is less than Zoo, 000, the impact resistance will be poor, and if it exceeds 300,000, the fluidity during molding will be insufficient.

The styrenic resin sheet A of the present invention, the styrenic resin sheet of the outer layer in the sheet ■, and the styrene resin sheet (B in the sheet ■)
) layer, the rubber-modified styrenic resin having the above-mentioned occlusion structure may be used alone, or in some cases, the rubber-modified styrene resin may be used to improve the gloss of the resulting sheet. Styrenic resin 20% by weight or more, preferably 30-85% by weight and general purpose polystyrene 80! i amount% or less, preferably 70-1
A mixture with 5% by weight may also be used.

In this case, if the amount of general-purpose polystyrene exceeds 80% by weight, the gloss will not improve in proportion to the amount, and impact resistance will decrease.

This general-purpose polystyrene is not particularly limited, and commercially available polystyrene obtained by polymerizing styrene monomers by a polymerization method such as bulk polymerization, suspension polymerization, or bulk-suspension polymerization can be used.

The styrenic resin sheet (2) of the present invention is a single-layer sheet whose base resin is a rubber-modified styrene-based resin having the above-mentioned occlusion structure alone, or a mixture of this rubber-modified styrene-based resin and general-purpose polystyrene, and includes, for example, First, the rubber-modified styrenic resin having the occlusion structure, the general-purpose polystyrene used as the case may be, and various additive components are blended in predetermined proportions, and the mixture is prepared using a Banbury mixer-1 single-screw extruder, a twin-screw extruder, a co-kneader, 180-2 by multi-screw extruder etc.
It can be made by preparing a resin composition by thorough kneading at a temperature in the range of 40°C, and then molding it by methods conventionally used in sort preparation, such as extrusion. can.

On the other hand, the styrenic resin sheet (2) of the present invention is a laminated sheet having a styrene resin sheet made of the above-mentioned base resin as an outer layer and a thermoplastic resin sheet as an inner layer. The base resin for the inner layer does not have to have a good glossy appearance and is not particularly limited, but polyolefin resins, general rubber-modified styrene resins having a salami structure,
Polycarbonate, polyester, polyacrylonitrile, polyvinyl chloride, etc. are used.

Examples of the polyolefin resin include σ-, such as ethylene, propylene, butene-1,3-methylbutene-1,3-methylpentene-1,4-methylpentene-1, etc.
Examples include olefin homopolymers, copolymers thereof, and copolymers of these and other copolymerizable unsaturated monomers. Typical examples include high-density, medium-density, and low-density polyethylene, linear polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and other polyethylenes. Examples include polypropylenes such as propylene homopolymers, propylene-ethylene block copolymers and random copolymers, propylene-ethylene-diene compound copolymers, polybutene-1, poly4-methylpentene-1, and the like. The thermoplastic resin layer may have a single layer, or may have multiple layers such as two or three layers.

In the styrene resin sheet (2) of the present invention, the outer layer has a thickness of 5 to 3000 μm, which is 1150 to 1/2 of the total thickness, and the inner layer has a thickness of 100 to 3000 pm. Adjustment is preferred. If the thickness of the outer layer is less than 1150 mm of the total thickness, the surface gloss may be poor.

In addition, between the outer layer and the inner layer, an adhesive layer such as modified polyolefin or ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, nylon, polyvinylidene chloride, saran, etc. A layer of gas barrier material such as aluminum foil may also be provided.

This styrene resin sheet (2) can be produced by a coextrusion molding method such as a multilayer blow molding method or a multilayer sort molding method. At this time, the molding temperature is usually 180 to 2
Selected within the range of 50°C.

In addition, the styrenic resin sheet (2) of the present invention has (A) a general-purpose polystyrene and/or rubber-modified styrenic resin foam sheet on the surface of (B) a base resin of the same type as that used for the styrenic resin sheet I. Thickness 5-100 consisting of
This is a foamed laminated sheet made of μm styrene resin films laminated.

If the thickness of the styrene resin film is less than 5 μm, the mechanical properties of the film will be insufficient, and if it is thicker than 100 μm, no improvement in the effect will be observed.

The base resin of the (A) layer foam sheet in the styrenic resin sheet (3) may be general-purpose polystyrene, a rubber-modified styrene resin, or a mixture thereof. The general-purpose polystyrene is not particularly limited, and commercially available polystyrene obtained by polymerizing styrene monomers by a polymerization method such as bulk polymerization, suspension polymerization, or bulk-suspension polymerization can be used.

Further, there is no particular restriction on the rubber-modified styrene-based resin, and any resin can be selected from among those conventionally used as rubber-modified styrene-based resins.

In the sea hm, the foam sheet of layer (A) preferably has a thickness of 100 to 3000 μm and a foaming ratio of 5 to 50 times. The thickness of this foam sheet is 1
If it is less than 3,000 μm, the mechanical properties are insufficient;
If it exceeds μm, there is a tendency for secondary processability such as ripening to deteriorate.

Further, if the expansion ratio is less than 5 times, the foaming effect will not be sufficiently exhibited, and if it exceeds 50 times, the mechanical properties tend to be insufficient.

The styrenic resin sheet of the present invention is extrusion laminated using a base resin constituting the styrenic resin foam of the (A) layer and a base resin constituting the styrenic resin film of the (B) layer. It can be manufactured by the method. At this time, there is no particular restriction on the foaming method for forming the foamed sheet of layer (A), and any method may be selected and used from among the methods commonly used in the conventional production of styrene resin foamed sheets. I can do it. For example, a method of obtaining a foamed sheet by mixing a chemical foaming agent into a base resin and heating it above the decomposition temperature of the foaming agent and above the melting and softening temperature of the base resin, and the molten state of the base resin in a molding machine. After injecting a physical blowing agent such as an inert gas or volatile liquid into the material,
Examples include a method of foam molding, and a method of impregnating the solid base resin with a volatile liquid and then heating it to a temperature higher than the melting and softening temperature of the resin to obtain a foam sheet. In particular, it is preferable to press a physical foaming agent such as a volatile liquid into the molten base resin and then perform foam molding.

Examples of the chemical blowing agent used during the foaming include azodicarbonamide, diazoaminobenzene, N, N
'-Dinitrosopentamethylenetetramine, p, p'-
Examples include oxybis(benzenesulfonylhydrazide), azobisisobutyronitrile, and sodium bicarbonate. These chemical foaming agents may be used alone or in combination of two or more, and may also be used in combination with a foaming aid if necessary.

Examples of volatile liquids used during foaming include dichlorodifluoromethane, trichlorotrifluoroethane, trichloromonofluoromethane, dichlorotetrafluoroethane, butane, pentane, hexane, etc. Alternatively, two or more types may be used in combination. Further, examples of the inert gas include nitrogen, carbon dioxide, argon, and mixed gases thereof.

In the present invention, the base resin used for the styrenic resin sheet I, the base resin used for the outer layer and inner layer of the sheet ■, the base resin used for the (A) layer and the (B) layer of the sheet ■, , various known additive components as necessary within a range that does not impair the purpose of the present invention, such as inorganic photoresists such as calcium carbonate, talc, mica, silica, and asbestos; reinforcing agents such as glass fiber, carbon fiber, and metal whiskers; Furthermore, lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide, organic polysiloxane, mineral oil, or two
, 6-di-t-butyl-4-methylphenol, stearyl-β(3,5-di-t-phthyl-4-hydroxyphenyl)propionate, triethylene glycol-bis-3-(3-t-butyl-4-hydroxy Hindered phenols such as -5-methylphenyl)propionate, tris(2,4-di-t-butylphenyl)phosphite, 4,4'-butylidenebis(3-methyl-6
-Add phosphorus-based antioxidants such as (butylphenyl-di-tridecyl) phosphite, ultraviolet absorbers, flame retardants, antistatic agents, mold release agents, plasticizers, dyes, pigments, other polymers, etc. be able to.

The styrenic sheet of the present invention can be aged, for example, by vacuum forming, pressure forming, or the like, to give a molded article of good quality and a desired shape.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

In addition, each characteristic was calculated|required as follows.

(1) Gel amount, swelling index Sample We (9) was dissolved in toluene, 15000
After centrifugation at rpm for 60 minutes, the supernatant was decanted to determine the amount of swollen insoluble components WS (g), and then the swollen insoluble components were vacuum dried at 60°C for 24 hours.
Determine the dry insoluble component amount Wg (g).

Gel amount (wt%) = (Wg/We) x 1o.

Swelling index - W s / W g (2) Glossiness It was determined in accordance with JISK-7105.

(3) Izot impact strength: Determined in accordance with J Is K-7110 (23°C, notched).

(4) At the center of the plate width (70 mm) at a point 125 mm from the gate position (end of the molded plate) of an injection molded plate with falling weight impact strength of 270 x 70 x 3 + nm, the load is 3.769 and the speed is 3.5 m/sec. ,
Measurement was performed using an automatic falling weight impact tester RDT5000 manufactured by Rheometrics under the conditions of a hole diameter of 2 inches in the sample fixing part and a temperature of 23°C, up to the point where the force first shows a sudden decrease in the force-displacement curve. Find the energy of , and use it as the falling weight impact strength t2.

(5) Flexural modulus It was determined in accordance with ASTM D-790.

(6) Melt index [MI]l5OR-11
It was determined in accordance with 33.

Production Example 1 Production of Single Occlusion Rubber Modified Polystyrene An SB block copolymer having a weight average molecular weight of 100,000 and a styrene unit content of 22.6% by weight [manufactured by Nippon Zeon Co., Ltd., trade name: ZLS-01
) 11679, styrene 30009, and 1 g of n-dodecyl mercaptan as a chain transfer agent, and heated at 300 rpm.
The reaction was carried out at 130° C. for 4 hours while stirring at m.

The reaction mixture 3 was then placed in a 1011 autoclave.
000 g, water 3000 g, polyvinyl alcohol log as a suspension stabilizer, benzoyl peroxide 6 g and dicumyl peroxide 3 g as polymerization initiators,
While stirring at 300 rpm, from 80°C to 30°O/
The temperature was raised to 140°C at a heating rate of hr, and the reaction was continued at that temperature for an additional 4 hours to obtain rubber-modified polystyrene beads.

Next, the obtained beads were pelletized using a single-screw extruder at 220° C., and then molded.

Table 1 shows the measurement results of the physical properties of the obtained molded article and the properties of the rubber-modified polystyrene.

Production Example 2 Production of single occlusion rubber-modified polystyrene SB block copolymer [manufactured by Nippon Zeon Co., Ltd., product name: ZLS] was placed in an autoclave with a capacity of 5C.
-01, styrene unit content 22.6% by weight, molecular weight 100,000] 704g, styrene 30009 and n-dodecyl mercaptan 1g as a chain transfer agent were added,
The reaction was carried out at 130° C. for 4 hours while stirring at rpm to obtain a prepolymer (1).

Similarly, a prepolymer (II) was obtained using polybutadiene (manufactured by Asahi Kasei Corporation, trade name: NF35AS) 4099 and 1 g of n-dodecyl mercaptan (the rubber structure was obtained under the following suspension polymerization conditions). Beads were synthesized and examined using an electron microscope to determine the occlusion of 0.4 μm and 1.
A salami structure of 2 μm was confirmed). Then, the prepolymer (I) 25509 obtained in the autoclave of 1011
, prepolymerized product (I[) 4509, 3000 g of water, 10 g of polyvinyl alcohol as a suspension stabilizer, 6 g of benzoyl peroxide and 3 g of dicumyl peroxide as polymerization initiators were added and heated at 80° while stirring at 500 rpm.
The temperature was raised from C to 140°C at a heating rate of 30"C/hour, and the reaction was continued for an additional 4 hours to obtain beads of rubber-modified polystyrene (occlusion was 0.4μ under an electron microscope).
Confirm that m1 salami is 1.2 μm ;). The obtained beads were pelletized using a single-screw extruder at 220° C., and then molded.

Table 1 shows the measurement results of the physical properties of the obtained molded article and the properties of the rubber-modified polystyrene.

(The following is a blank space) 1 Table Next, examples and comparative examples of styrenic resin single layer 7-sheet (sheet I) are shown.

Example 1 Using a rubber-modified styrenic resin (occlusion HIPS) having an occluded structure obtained in Production Example 2,
A specimen for physical properties was prepared by injection molding, a sheet was prepared by extrusion molding, and then a thermoformed article was prepared by ripening (vacuum forming) using this sheet, and each physical property was determined. The results are shown in Table 3.

The sheet forming conditions and ripening (vacuum forming) conditions are shown below.

Nto molding conditions Nto molding machine: manufactured by Shinko Kikai Seisakusho Co., Ltd., 35 mm extruder Molding conditions/Set temperature 190°C 210°C 220'C 220°C 220°C 5-C ・Screw rotation speed: 130 r Pm (MAX)・
Take-up speed: 0.7 m/min ・Sheet thickness: 1.5++1 m ・Lip opening: 2.0 mm Aging mold (vacuum forming) conditions Vacuum forming machine: Manufactured by Yono Research Institute Co., Ltd., large-scale air pressure vacuum forming machine Molding conditions: Conditions shown in the $2 table (blank below) Table Example 2 Occlusion HIP5501 obtained in Production Example 1! Quantity and general purpose polystyrene (GPPS) C Idemitsu; L tyrol HH
30, produced by Idemitsu Petrochemical Co., Ltd., and a part of Ml 41501i, and then kneaded using a single-shaft mixer at a temperature of 200° C. and a rotation speed of 8 Orpm to form pellets.

Next, using this pellet, physical property test pieces, sheets, and thermoformed products were created in the same manner as in Example 1, and each physical property was determined. The results are shown in Table 3.

Comparative Example 1 In Example 1, the occlusion HI obtained in Production Example 2
HIPS r Idemitsu styrene ET66J instead of PS
Manufactured by E Idemitsu Petrochemical Co., Ltd., good gloss, extrusion grade]
It was carried out in the same manner as in Example 1 except that . The results are shown in Table 3.

Comparative Example 2 In Example 2, the occlusion HI obtained in Production Example 1
It was carried out in the same manner as in Example 2 except that HIPSr Idemitsu Styrene ET66J was used instead of PS. The results are shown in Table 3.

(Hereinafter, blank spaces) Next, Examples and Comparative Examples of styrenic resin laminate sheets (Sheet II) will be shown.

Example 3 Rubber-modified styrenic resin having an occlusion structure obtained in Production Example 1 (occlusion HIPS), ethylene-vinyl acetate copolymer (EVA) as an adhesive [Ultracene UE634, manufactured by Tosoh Corporation], and polypropylene Using (PP) as a raw material, a laminated 7-sheet with a total thickness of 0.1 mm was produced using a three-layer, three-layer T-die molding machine. The thickness ratio of each layer was adjusted to be styrene resin layer/adhesive layer/polypropylene resin layer = 40/30/30, and coextrusion molding was performed with the resin temperature in each screw at 200 to 220°C.

The glossiness of the styrene resin side of the obtained laminated sheet and the T peel strength between the styrene resin layer and the polypropylene resin layer were measured. The results are shown in Table 4.

Example 4 In Example 3, a blend of 350 parts by weight of Occlusion HIP obtained in Production Example 1 and 50 parts by weight of general-purpose polystyrene [Idemitsu Styrene HH30, manufactured by Idemitsu Petrochemical Co., Ltd., MI4] was used as the styrenic resin. teeth,
It was carried out in the same manner as in Example 1. The results are shown in Table 4.

Example 5 In Example 3, the occlusion HI obtained in Production Example 1
Occlusion HIPS obtained in Production Example 2 instead of PS
The same procedure as in Example 3 was carried out except that . The results are shown in Table 4.

Comparative Example 3 In Example 3, the occlusion HI obtained in Production Example 1
Instead of PS, rubber-modified polystyrene [Idemitsu Styrene HT55, manufactured by Idemitsu Petrochemical Co., Ltd., MI2. The same procedure as in Example 3 was carried out except that O] was used. The results are shown in Table 4.

(Left below) Next, styrene resin foam laminated sheet (Sheet III)
Examples and comparative examples are shown below.

Example 6 Using the rubber-modified styrene resin having an occlusion structure obtained in Production Example 2 (occlusion HIPS), physical property test pieces were prepared by injection molding.

Also, put this occlusion HIPS into an extruder,
Make sure it is on the laminate side, and use Idemitsu Styrofoam ET.
66 [manufactured by Idemitsu Petrochemical Co., Ltd., good gloss, extrusion grade]
A laminated notebook is formed by co-extrusion using the foamed layer as an inner layer under the molding conditions shown below, and this sheet is then aged (vacuum formed) under the conditions shown below to create a molded product. I asked for The results are shown in Table 5.

In addition, the foaming of the foamed sheet layer in the laminate sheet @
The rate was 20 times higher.

/-T molding conditions/extruder setting temperature [laminate side] HI H2H3H4H5 190°C-21000-220'O-220'C-2
20'C! [Inner layer] HI H2H3H4H5 140°C-150°0-160°O-160°C-16
0℃・Touch roll temperature 85℃・Screw rotation speed 13 Or pm (Max)・
Take-up speed 0.7 m/min, 7-t thickness Laminate side 50 μm Inner layer 1.5 mm Aging type (vacuum forming) conditions Vacuum forming machine: Large-scale pressure vacuum forming machine manufactured by Yono Research Institute Co., Ltd. Molding conditions: The above-mentioned section Conditions shown in Table 2 Example 7 550 parts by weight of Occlusion HIP obtained in Production Example 1 and general purpose polystyrene (GPPS) [Idemitsu Sue F-Roll HH
30, manufactured by Idemitsu Petrochemical Co., Ltd., MI4] and 50 parts by weight.
A pellet was obtained by kneading at 00°01 rotation speed of 8 rpm. This pellet was injection molded to obtain a physical property test piece.
When the glossiness, flexural modulus, and Izotsu impact strength were measured, the glossiness was 98% and the flexural modulus was 27.500 kg.
/cm”, Izotsu impact strength is 7.5kg・cm/c
It was m.

Next, the pellets were put into an extruder so that they were on the laminate side, while the foamed layer of Idemitsu Styrofoam HH30 was used as the inner layer, and the same procedure as in Example 6 was carried out to form a laminated and thermoformed product. were prepared and their physical properties were determined. The results are shown in Table 5.

Comparative Example 4 In Example 6, the occlusion HI obtained in Production Example 2
HIPSr Idemitsu styrene ET66J instead of PS
It was carried out in the same manner as in Example 6 except that [manufactured by Idemitsu Petrochemical Co., Ltd., good gloss, extrusion grade] was used. The results are shown in Table 5.

Comparative Example 5 In Example 7, the occlusion HI obtained in Production Example 1
It was carried out in the same manner as in Example 7 except that HIPSr Idemitsu Styrene ET66J was used instead of PS. The results are shown in Table 5.

(The following is a blank space) [Effects of the invention] The styrenic resin sheet tray of the present invention is a single-layer sheet based on a rubber-modified styrene-based resin having an occlusion structure, or a mixture of the rubber-modified styrene-based resin and general-purpose polystyrene; The styrenic resin sheet (■) is a laminated sheet having the above-mentioned base resin as an outer layer and the thermoplastic resin sheet as an inner layer, and the styrene-based resin sheet (2) is a laminated sheet having the above-mentioned styrene-based resin sheet I on the surface of the styrene-based resin foam sheet. This is a foamed laminated sheet made by laminating styrene-based resin films made of the same material as the material resin, and the styrene-based resin sheet I has an excellent balance of gloss, rigidity, and impact resistance, and has almost no loss in gloss even when thermoformed. In addition, styrene resin sheets (1) have characteristics such as excellent gloss and impact resistance, and these styrene resin sheets are suitably used as materials for parts of, for example, home appliances and OA equipment. On the other hand, the above-mentioned styrene resin sheet (■) has an excellent balance of gloss, rigidity, and impact resistance, and also has an aged form i=*+-aj, ! It has characteristics such as good heat insulation properties and is suitable for use as a material for polystyrene vapor molded products such as instant foods, various food containers, and meat trays. .

Claims (1)

[Scope of Claims] 1. A styrenic resin formed by molding a rubber-modified styrenic resin alone or a mixture of 20% by weight or more of this rubber-modified styrene-based resin and 80% by weight or less of general-purpose polystyrene, whose dispersed rubber form has an occlusion structure. sheet. 2 The outer layer is a styrenic resin sheet made of a rubber-modified styrenic resin alone or a mixture of 20% by weight or more of this rubber-modified styrene-based resin and 80% by weight or less of general-purpose polystyrene, and a thermoplastic resin whose dispersed rubber form has an occlusion structure. A styrene resin sheet made by laminating sheets as an inner layer. 3. The styrenic resin sheet according to claim 2, wherein the thermoplastic resin sheet is a polyolefin resin or a rubber-modified styrene resin sheet having a salami structure. 4. The styrenic resin sheet according to claim 2 or 3, wherein the outer layer has a thickness of 5 to 3000 μm, and the inner layer has a thickness of 100 to 3000 μm. 5. On the surface of (A) general-purpose polystyrene and/or rubber-modified styrenic resin foam sheet, (B) a rubber-modified styrenic resin alone or 20% by weight or more of this rubber-modified styrenic resin and a general-purpose rubber-modified styrenic resin whose dispersed rubber form has an occlusion structure. Thickness 5 consisting of a mixture with not more than 80% by weight of polystyrene
A styrene resin sheet made by laminating styrene resin films of ~100 μm. 6 The foam sheet of the (A) layer has a thickness of 100 to 3000μ
6. The styrenic resin sheet according to claim 5, which has a foaming ratio of 5 to 50 times. 7 The rubber-modified styrenic resin having an occlusion structure has a dispersed rubber morphology with an occlusion structure having a plane of symmetry, and has an area average particle diameter of 0.1 to 0.7 μm,
The ratio of the area average particle diameter to the number average particle diameter is 1.0 to 2.
．． 7. The styrenic resin sheet according to claim 1, wherein a rubber-like polymer is dispersed in a styrenic polymer as the particles. 8 Dispersed particles of rubbery polymer meet the relational expression K=φ_R{1-[[(D_S/2)-λ]/(D_
S/2)]^3}^-^1 (φ_R in the formula represents the volume fraction of the rubbery polymer in the rubber-modified styrenic resin, and D_
S indicates the area average particle size (diameter) of the rubbery polymer, and λ
8. The styrenic resin sheet according to claim 7, wherein the thickness of the rubbery polymer phase is 0.10 μm or less.