JPH0122298B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition comprising polypropylene and polystyrene, and more particularly to a stable resin composition in which polystyrene is finely and uniformly dispersed in a polypropylene matrix, and a method for producing the same. Polypropylene (hereinafter sometimes abbreviated as PP) has excellent physical properties such as impact resistance, tensile strength, and bending resistance, but it lacks rigidity compared to PS.
In order to supplement this rigidity with polystyrene (hereinafter sometimes abbreviated as PS), various attempts have been made to melt and mix PS with PP. However, PP and PS have poor compatibility, and simply melt-mixing the two causes phase separation, making it impossible to obtain a resin composition with practical strength. Therefore, various studies have been conducted to improve the compatibility between PP and PS.
It has been proposed to blend and melt-mix a third component, such as an elastomer such as polybutadiene, ethylene-propylene rubber, or chlorinated polypropylene, which has a certain degree of affinity for both.
However, these conventionally proposed PPs
PS resin compositions have drawbacks such as insufficient dispersibility by melt mixing, and mixing of elastomers lowers the desired rigidity and is economically disadvantageous. In order to obtain a composition of PP and PS that is excellent in both high rigidity, impact resistance, and tensile strength, the present inventors have conducted extensive research with the aim of creating a stable resin composition in which PS is finely and uniformly dispersed in a PP matrix. As a result, we found that if we use a resin compound obtained by adding PP, PS, and solid fine powder and mixing them under specific conditions, the PP and PS can be melt-molded without phase separation. The present inventors have discovered that a stable and highly rigid resin composition in which PS is finely and uniformly dispersed in a PP matrix can be obtained, and have completed the present invention. According to the invention, polypropylene 70
Polypropylene and polystyrene, characterized in that 30 to 150 parts by weight of solid fine powder are uniformly blended into a molten resin mixture consisting of ~98% by weight and 30 to 2% by weight of polystyrene, per 100 parts by weight of the resin mixture. A resin composition is provided. Furthermore, according to the invention, polypropylene 70~
98% by weight and 30-2% by weight of polystyrene, and per 100 parts by weight of polypropylene and polystyrene
30 to 150 parts by weight of solid fine powder is charged into a high-speed rotating mixer, and mixed at high speed while heating to a temperature higher than the melting temperature of both the polypropylene and polystyrene resins to obtain the solid fine powder. As soon as a partially fused porous aggregate of the resin powder coated with the powder is formed, it is immediately cooled and solidified to produce a resin compound, which is then optionally treated with an aqueous medium and then melted. Also provided is a method for producing a resin composition comprising polypropylene and polystyrene, which is characterized by molding. The "polypropylene" used as the matrix in the resin compositions of the invention includes homopolymers of propylene (especially isotactic polypropylene) and small amounts of up to 5 mol % of comonomers such as ethylene, ethyl acrylate, ethyl methacrylate. or a propylene copolymer containing a graft unit of an unsaturated carboxylic acid. In addition, the "polystyrene" dispersed in the polypropylene matrix includes a styrene homopolymer [for example, general purpose (GP grade polystyrene)] and 10 mol%
Styrene copolymers containing monomer units of comonomers such as butadiene, ethylene, ethyl acrylate, ethyl methacrylate in small amounts up to
impact)] is included. PS for PP as the above matrix resin
The mixing ratio of the former is 70 to 98% by weight, preferably 85 to 95% by weight, and the latter is 30 to 2% by weight, preferably 15 to 5% by weight, based on the total amount of both. be able to. If the mixing ratio of polystyrene is more than 30% by weight, the resulting resin composition tends to be brittle, while if it is less than 2% by weight, the rigidity cannot be improved and there is no point in adding PS. As the solid fine powder that can be incorporated into these resins according to the present invention, any solid fine powder commonly used as a filler for resins can be used. Therefore, solid fine powders that can be suitably used in the present invention include, for example, grain flours such as starch and wheat flour; plant powders such as wood flour; resin powders such as urea resin, melamine resin, and phenol resin; ,
Examples include metal powder such as aluminum; inorganic powder such as talc, clay, calcium carbonate, silica, alumina, and glass powder. These solid fine powders can be used alone or in combination of two or more. In the present invention, in particular, talc with an average particle size of 1 to 15 microns,
Calcium carbonate, clay, silica and alumina are preferably used. Also, a portion of the solid fine powder, generally up to 20% by weight of the total amount of the solid fine powder used, preferably 10
Less than % by weight can be replaced by organic short fibers such as pulp, cotton, silk, linen, wool, synthetic fibers, and regenerated fibers, or inorganic short fibers such as glass fibers, carbon fibers, and asbestos. By using these short fibers in combination, the mechanical strength of the resin molded product can be significantly improved. The particle size of the solid fine powder used in the present invention is not strictly limited and can be varied widely depending on the type of resin and the physical properties required for the resin molded product, but generally the average particle size is 100 microns or less,
Preferably it is in the range of 0.1 to 50 microns, more preferably in the range of 0.5 to 30 microns. In addition, when using short fibers as described above, the fiber length is generally 10 mm or less, preferably 5 mm.
mm or less, and the fiber diameter is generally 100 microns or less, preferably in the range of 1 to 50 microns. The blending amount of such solid fine powder is the total of PP and PS.
30 to 150 parts by weight, preferably 60 parts by weight per 100 parts by weight
~100 parts by weight. If the amount of solid fine powder blended is less than 30 parts by weight, it will be difficult to achieve fine dispersion of PS in the PP matrix.
There is also a tendency for the resulting composition to lack stability; on the other hand, if the amount exceeds 150 parts by weight, the resulting resin composition tends to be brittle. The aforementioned PP and PS are treated together with the solid fine powder as described below to prepare a resin powder coated with the solid fine powder and composed of PP and/or PS. At that time, it is important that the solid fine powder is attached and buried in an exposed state on the surface of the resin powder (but of course, the resin powder also has the solid powder inside it). may contain dispersed bodies). The amount of solid fine powder adhered to and embedded in the resin powder particles is determined by the fact that most of the surface of each resin powder particle is covered with the exposed solid powder, and when observed with an electron microscope at a magnification of 300 times, the resin powder particles are It is desirable that the amount be such that the base of the body is hardly visible. Moreover, the resin powder particles exposed and coated with solid fine powder in this way generally aggregate in large numbers, and the individual powder particles partially fuse with each other to form a porous mass. suitable. The particle size of such porous agglomerates is usually in the range of 0.1 to 20 mm, preferably 0.3 to 5 mm. Therefore, if the particle size is larger than this, it is preferable to use a pulverizer, mixer, etc. to reduce the particle size to the above range. One promising method for preparing such a porous aggregate is to mix the aforementioned mixture of PP, PS, and solid fine powder with a high-speed (vortex) mixer, such as a Henschel mixer (manufactured by Mitsui Miike Manufacturing Co., Ltd.). There is a method of high speed mixing in a mixing tank such as Super Mixer (manufactured by Kawada Seisakusho) while heating to a temperature above the melting temperature of PP and PS. Heating of the resin is carried out by circulating steam or oil through the jacket of the mixing tank, or by generating heat from mixing friction. When both PP and PS resins begin to melt to their melting temperature during heating and mixing at high speed rotation, the resistance to the mixing rotational force of the mixer increases rapidly, causing the rotational resistance (or current) of the mixer motor to fluctuate. This turbulent high-speed mixing is generally conveniently continued for about 50 to about 250 seconds, preferably about 70 to about 200 seconds, from the point at which the motor's rotational resistance (or current) begins to increase turbulently. The change in the shape of the resin at temperatures above the melting temperature in the mixing tank of the high-speed mixer mixer is only caused by mutual fusion of the resins when only the resin is mixed by heating, but in the case of the present invention In this case, the solid fine powder adheres to the resin surface and the resin is deformed while preventing mutual fusion of the resins, which is different from the above case. (1) Until the melting and deformation of the resin begins and the mixing rotary motor current begins to increase in a turbulent manner, the resins do not interact with each other, regardless of whether the resins are supplied in pellet or powder form. Not fused,
The resin and solid fine powder are simply mixed and dispersed. (2) However, the resin gradually melts and deforms into flaky flakes, which are then torn off one after another into thin flakes and powder particles. At the same time, the solid fine powder adheres to and is partially embedded in the surface of the powdery resin, and the thin flaky powdery surface of the resin is covered with the fine powder. At that time, PP exhibits the behavior of the above resin, but PS
Because it has a slightly lower melting point than PP, has a greater ability to fuse to solid fine powder, and has a small relative amount and is not compatible with PP, it tends to form a flat flake shape or thin flake shape than PP, and does not adhere to solid fine powder. Finely dispersed. In other words, it is presumed that the fine solid powder is partially embedded in the PP powder with PS attached, and the surface of the fine PP powder is covered with the fine solid powder with finely dispersed PS attached. Ru. (3) Further, the adhesion of the solid fine powder particles to the resin surface progresses, and the molten resin seeps out from between the solid fine powder coating the resin surface, and/or through the free resin pieces, and/or the solid particles adhere to the resin surface. The resin powder particles coated with the solid fine powder are partially fused to each other on the minute exposed surfaces to which the fine powder is not attached, forming a porous aggregate. (4) At this point, the porous agglomerate is discharged out of the mixing tank, sprinkled with water and/or blown with air, and optionally rotated at low speed to cool and solidify. Alternatively, by passing cooling water through the jacket of the mixing tank and blowing air onto it, the mixture can be cooled and solidified within the mixing tank, thereby obtaining the resin compound made of the porous agglomerates of the present invention. In the resin compound thus obtained,
As mentioned above, PS exists in a state in which it is finely dispersed and attached to solid fine powder, so when the resin compound is melted and kneaded, PS agglomeration is prevented and it is stably finely dispersed even in the PP matrix. It is estimated to be. The mixing device used in the present invention is not limited to a high-speed mixer, and any mixer having the same functions as those described above may be used. Among the equipment that is easily available today, high-speed mixing mixers can be used as is and are often used, but other mixing machines such as ribbon blenders can be modified to have a strong high rotational force. It can be used for. In addition, when preparing the above-mentioned porous aggregate, in addition to the resin and solid fine powder, resin additives such as antioxidants, surfactants, colorants, ultraviolet absorbers, flame retardants, etc. may be added as necessary. . In particular, surfactants and antioxidants are desirable resin additives for the highly filled thermoplastic surfaces produced by the present invention. Surfactants work at the interface between resin and solid fine powder and help promote dispersibility, such as fatty acid alkanolamide, fatty acid monoglyceroid,
Nonionic surfactants such as polyethylene glycol fatty acid esters; anionic surfactants such as fatty acid amides, fatty acid metal salts, alkyl sulfate types, alkyl phosphate types; cationic surfactants such as ammonium salts; fatty acids; polyethylene glycol, polypropylene Polyhydric alcohols such as glycol and glycerin; Ethers such as polyethylene glycol diethyl ether;
Polyvinyl alcohol and the like or mixtures thereof are included, and these surfactants can be charged into a mixer and mixed together with the resin and the solid fine powder, or can be attached to the surface of the solid fine powder particles in advance and then mixed with the resin. On the other hand, antioxidants are generally already blended into commercially available resin pellets, but the method of the present invention uses a large amount of fine powder and goes through the heating melt mixing process as described above. It is desirable to add more in proportion to the amount of solid fine powder used. Examples of antioxidants include thiopropionic acid ester antioxidants such as dilauryl thiodipropionate; phenolic antioxidants such as alkylphenols and alkylbisphenols;
Alternatively, a mixture thereof may be used. The antioxidant is usually per 100 parts by weight of solid fine powder.
The surfactant is used in an amount of 0.01 to 5 parts by weight, and the surfactant can generally be blended in an amount of 0.1 to 10 parts by weight per 100 parts by weight of solid fine powder. Examples of colorants include dyes and pigments such as cadmium red, chrome orange, chrome yellow, chrome green, cobalt aluminate blue, titania, phthalocyanine blue, and azo dyes, and examples of ultraviolet absorbers include salicylic acid. Examples of flame retardants include those commonly used as resin additives, such as phosphoric acid esters, halogenated hydrocarbons, and antimony oxides. It can be blended in normal amounts. The porous aggregate prepared in this way differs from the conventional structure in which solid fine powder is kneaded into resin and the solid fine powder is buried and dispersed in the resin. Covering the surface of the resin powder in a state where it is partially embedded and attached to the resin surface,
Moreover, the coated resin powder particles are partially fused to form a porous aggregate. Although this difference in structure is obvious under a microscope in both the cross section and the surface, the adsorption rate of water vapor is used here as a numerical index representing the appearance of the solid fine powder and its porous aggregate structure. However, "water vapor adsorption rate" means temperature 25℃, relative humidity 30%, pressure
Weight after being kept in a constant temperature and humidity room at 1 atm for 24 hours: W ₁
g of porous aggregates at a temperature of 105°C and a water vapor pressure of
After keeping it in a closed atmosphere of 1.2 atm for 1 hour, take it out and leave it on a paper for 3 minutes, then put it in a drying oven at 105℃ for 3 minutes, and immediately weigh it.
In the case of W ₂ g, it is a value calculated by the following formula. Water vapor adsorption rate (%) = W ₂ − W ₁ /W ₁ ×100 The porous aggregate produced by the present invention has a very high water vapor adsorption rate, and the value is generally 0.05% or more. The content is more preferably 0.3% or more. The resin compound made of the above-mentioned porous agglomerates can be directly supplied to various molding machines and melt-molded. For example, the oxidized compound can be melt-kneaded by feeding it into a conventional extruder equipped with a vent device for degassing the resin as it melts, and then extrusion or injection molding, or it can be roll calendered. or may be press molded.
Such melt molding operations and equipment are not particularly special, and can be performed using methods and equipment that are known per se. Thereby, resin molded products such as films, sheets, irregularly shaped objects, etc. can be processed from the resin compound. According to another aspect of the present invention, the resin compound prepared as described above is treated with an aqueous medium prior to melt molding to cause the aqueous medium to adhere to and retain the porous aggregate. If a resin compound treated with a medium is melt-kneaded under pressurized conditions in which evaporation of the aqueous medium is substantially suppressed, and then the melt-kneaded resin composition is released from the pressurized conditions, a resin foam can be obtained. It can be formed into. In this case, the aforementioned solid fine powder used for preparing the resin compound has sufficient hydrophilicity by itself, but in order to further improve the wettability of the surface to water, the solid fine powder is added to the resin compound. Prior to preparation, the resin may be treated with a surfactant as described above to further increase hydrophilicity and improve the affinity between the resin and the fine powder. In particular, if the solid fine powder to be used is considered to be relatively hydrophobic, the surface may be treated with a surfactant such as those mentioned above, or a hydrophilic substance such as polyvinyl alcohol, fatty acids, polyhydric alcohols, or ethers. It is convenient to use it after imparting hydrophilic properties. Water is generally used as the aqueous medium for treating resin compounds prepared using such hydrophilic solid fine powder, but it is difficult to adjust the boiling point and vapor pressure of the medium, and to control the porous aggregate. For the purpose of increasing affinity, improving dispersion stability of aqueous media during melt-kneading of resin compounds, and improving bubble uniformity, surfactants, water-soluble polymers, polyhydric alcohols, and water-miscible organic A solvent and the like can be added as appropriate. As surfactants, those mentioned above can be used, and these are generally 0.1
It can be added at a concentration of ~50g/, preferably 1-10g/. As water-soluble polymers and polyhydric alcohols, for example, the degree of polymerization is about 500 to
Polyvinyl alcohol with a saponification degree of about 2000 and 85% or more, mono or polyethylene glycol with a number average molecular weight of up to 400, glycerin, etc. are included, and these are generally 1 to 100 g /
Preferably, it can be added at a concentration of 10 to 50g/. Further, water-miscible organic solvents that can be used include, for example, alcohols such as methanol, ethanol, propanol, and cyclohexanol; esters such as ethyl acetate and butyl acetate; ethers such as diethyl ether, dioxane, and trioxane; acetone, Examples include ketones such as methyl ethyl ketone, and generally 1 to 100
g/, preferably 10 to 50 g/. The amount of the aqueous medium mentioned above can be varied over a wide range depending on the desired expansion ratio of the foam, but in general, the amount of the porous aggregate 100
It can be 1 to 15 parts by weight, preferably 2 to 5 parts by weight. Treatment of the resin compound with an aqueous medium can be carried out by combining the two and mixing in a mixer. The resin compound treated with the aqueous medium as described above is then melt-kneaded under pressurized conditions in which evaporation of the aqueous medium is substantially suppressed. This melt-kneading can be carried out in the same manner as melt-kneading during the production of ordinary resin foams, and can be carried out using an extruder such as a non-vented single-screw extruder or a non-vented multi-screw extruder. . Here, "pressurized conditions under which evaporation of the aqueous medium is substantially suppressed" refers to pressure conditions higher than the vapor pressure of the aqueous medium impregnated in the resin compound at the melt-kneading temperature. The operation of the extruder is not special and can be carried out by a method known per se. The resin composition sufficiently melted and kneaded in this way is
Extrude it through die lips of various shapes in the molten state, or
The mixture is injected into a suitable mold or placed in a press molding machine, released from the pressurized state, and foamed and solidified. As a result, resin foams processed into shapes such as corrugated sheets, flat sheets, stretched sheets, and irregular extrudates are obtained. Furthermore, according to the invention, the resin compound prepared as described above is mixed with a thermally decomposable blowing agent or a low-boiling liquid or liquefied gas type blowing agent, especially the former thermally decomposable blowing agent. A resin foam molded product can also be made by melt-kneading and molding as described above. Examples of thermally decomposable foams that can be suitably used include inorganic blowing agents such as (bi)carbonate; organic blowing agents such as azodicarbonamide and dinitrosopentamethylenetetramine; or mixtures thereof. These blowing agents are the resin compound 100 mentioned above.
It can be added at a ratio of 0.5 to 10 parts by weight per part by weight. Melting and kneading of a resin compound to which such a heat-foaming foaming agent is added can be carried out by a method known per se, but it is desirable that the discharge temperature be slightly lower. According to the method of the present invention described above, a resin composition can be obtained in which polystyrene is uniformly finely dispersed together with solid fine powder in a polypropylene resin matrix. Such a resin composition has the impact resistance, tensile strength, bending resistance, etc. of polypropylene and the rigidity of polystyrene, and with the addition of the filling effect of solid fine powder, various excellent practical uses can be obtained. For example, tangible packaging containers such as trays, lunch boxes, and packages currently used for tableware packaging are consumed in large quantities as one-way containers, and many are made of high-impact polystyrene, styrene paper (styrene foam sheet), polypropylene, etc. However, the waste of these materials poses a pollution problem, and when incinerated, PS-based materials have the problem of generating black smoke and soot, and PP-based materials have a high calorific value. Various problems have occurred, including damage to incinerators. As a countermeasure, it is possible to use polyolefin filled with inorganic fine powder, but at the amount of filling required to obtain the physical properties (strength) for use, the stiffness is lower than that of PS sheet, and it is necessary to use a thick sheet. Uniform dispersion and molding of the solid fine powder require a large amount of work, making it difficult to reduce costs. Since the resin composition provided by the present invention has PS added to the PP matrix filled with solid fine powder, it has higher rigidity than high impact polystyrene and can be used with a thinner wall thickness.
In addition, it has a uniform composition, high physical properties, good color and texture, and is easy to process, improving quality and productivity, and reducing product costs, among other advantages. have.
This advantage is the same even for foams; in particular, when foams are produced using an aqueous medium, high quality and high productivity can be obtained as well as the hygiene and safety of the foaming agent. The method of the present invention will now be further illustrated by examples. Example 1

[Table] Using a high-speed mixing mixer (Super Mixer SMG100 manufactured by Kawada Seisakusho, mixing electric motor 22KW, 4P/8P), the mixing tank (tank capacity 100) was heated by circulating heated oil at 140° to 150°C through the jacket. Ta. All of the above formulations were put into the mixing tank of the mixer and mixed at high speed. After about 20 minutes, the mixing motor current began to fluctuate and increase (mixture temperature: 195°C), and after 80 seconds, it suddenly increased and reached 80A (mixture temperature: 210°C) in 40 seconds (120 seconds in total), so the discharge port The mixture was released using a . The discharged mixture is rapidly cooled and coarsely crushed by a low-speed rotating mixer with strong air cooling to obtain a resin compound consisting of partially fused porous aggregates of fine resin powder coated with fine powder. Ta. Next, the particles were crushed to a maximum particle size of 5 mm or less using a crusher and then fed into an extruder. On an extrusion sheet line equipped with a coat hanger die attached to a 70-mm extruder with a vent, and an air knife, polishing roll, and take-up machine installed at the die lip, the above resin compound was extruded at a maximum extruder temperature of 240℃ and a die temperature of 220℃. The film was formed by extrusion. This blend sheet is vacuum-formed or pressure-formed into trays for light food packaging, and compared to high-impact polystyrene sheets of the same type and thickness, it has a 30% higher rigidity in use and is easier to form. It was good, and the color tone and texture were suitable. Example 2 2.5 parts by weight of tap water containing 0.5% diethylene glycol was added to 100 parts by weight of a resin compound with a maximum particle size of 5 mm or less produced in exactly the same manner as in Example 1, and the mixture was mixed for 5 minutes to undergo an aqueous medium impregnation treatment. A resin compound was obtained. This resin compound was supplied to a non-vent type 70 mm extruder equipped with a circular die and air rings installed inside and outside the die lip to cool the tip of the die lip and the extruded sheet. The operating conditions of the extruder are as follows. Circular die/mandrel blow ratio: 2.6x Mandrel circulating hot water temperature: 80℃ Extruder cylinder maximum temperature: 225℃ Die temperature: 195℃ Resin temperature: 198℃ Resin pressure: 220Kg/cm ² die lip temperature: 179.8~180℃ Extrusion The sheet was pulled out while being stretched by a take-up machine and cut into pieces, and a foamed sheet was obtained by a wind-up machine. The obtained foam sheet has a thin skin layer on the surface, and has a closed cell structure as a whole with no bubble breakage, and the cell diameter is mostly 0.5 mm or less, and most of them are 0.1 to 0.1 mm.
It was a homogeneous foam of 0.3 mm, and the foaming ratio (volume ratio) was about 8 times. This foamed sheet is suitable for use in vacuum forming food packaging containers such as trays, and can also be used as a substitute for high-grade white paperboard. Example 3 To 100 parts by weight of a resin compound with a maximum particle size of 5 mm or less produced in exactly the same manner as in Example 1, a blowing agent: carbonate type (Hydrocellol, manufactured by Behringer Ingelheim, West Germany) was added.
1.5 parts by weight of azodicarbonamide (Uniform AZ-H, manufactured by Otsuka Chemical Co., Ltd.) 1 part by weight was added and mixed, and the same extruder and circular die used in Example 2 were used as follows. Maximum extruder cylinder temperature: 205℃ Die temperature: 190℃ Resin temperature: 200℃ Resin pressure: 260Kg/cm ² die lip temperature: 170゜±2℃ The extruded sheet is cooled with an air knife, taken out, cut, and passed through a winding machine. A foamed sheet was obtained. The surface of the foamed sheet obtained had some roughness due to minute bubble breakage, and there were also open cell areas with a bubble diameter of 0.5 m/m to 1 mm, and the foaming ratio was about 12 times. Example 4

[Table] The above components were charged into the same mixer as used in Example 1 and mixed. 17 minutes after the start of mixing, the temperature of the mixture reached 195℃, and after another 2 minutes, the temperature of the mixture suddenly reached 205℃.
The outlet was opened to release the mixture. The released mixture was cooled and ground as in Example 1, and the resulting resin compound was fed to the same extruder and Sheetlite as used in Example 1, and the resin compound was heated at a maximum extruder temperature of 220°C and a die temperature of 200°C. The compound was extruded into a film. This blend sheet has high rigidity and is somewhat brittle, but
When used as buffer holding materials, such as packs for fruits and vegetables (currently pulp packs are the mainstream), the same type as pulp products has approximately 10 to 20% of the weight of pulp products and exhibits almost the same physical properties in use. Comparative example 1

【table】

[Table] Pour the above mixture into a ribbon blender and
Dry blended for 30 minutes at °C. The obtained mixed dispersion was produced into a 0.8 mm thick sheet using a 50 mm extruder with a width of 500 mm and a JIS K-6
We attempted to measure its mechanical properties using 758.
However, in the obtained film, granular agglomerates of calcium carbonate were observed with the naked eye, and the film was broken due to insufficient dispersion, so that no measurement values could be obtained. Comparative Example 2 A blend having the same composition as described in Comparative Example 1 was charged into a Banbury mixer, kneaded and melted at 210°C for 11 minutes, and the molten mixture was pelletized using an extrusion pelletizer. A 0.8 mm thick sheet (sheet A) was produced from the pellets using a 50 mm extruder with a width of 500 mm and a T-die, and its mechanical properties were measured according to JIS K-6 758.
The results are shown in the table below. In addition, a resin compound was produced by treating a formulation having the same composition as described in Comparative Example 1 in the same manner as described in Example 1, and this resin compound was molded into a sheet in the same manner as above. (Sheet B). The mechanical properties of this sheet are also shown in the table below.

[Table] *There is some variation Further, the above sheets A and B were vacuum formed using a cup mold with a diameter of 60 mm and a depth of 30 mm, under the same heating cycle. As a result, sheet A (comparative example)
In the case of , the resulting cotsup had voids at the bottom corners where the elongation was significant, exhibited pearlescent luster, and decreased rigidity, making it unsuitable for practical use. On the other hand, in the case of sheet B (the present invention), the obtained cotsup did not have significant elongation or voids even at the bottom corners, had no stiffness or decreased rigidity, and had almost no defective rate. However, a product that can be put to practical use was obtained.

Claims (1)

[Claims] 1 70-98% by weight polypropylene and polystyrene
A solid fine powder of 30 to 2% by weight and 30 to 150 parts by weight per 100 parts by weight of polypropylene and polystyrene in total is charged into a high-speed rotating mixer, and the melting temperature of both the polypropylene and polystyrene resins is adjusted in the high-speed rotating mixer. The polypropylene is heated to a temperature above and mixed at high speed, and immediately cooled when a porous agglomerate of partially fused resin powder coated with the solid fine powder is formed. A method for producing a resin compound consisting of and polystyrene.