JPH0657085A - New rubber-modified styrenic resin composition - Google Patents

Abstract

PURPOSE:To provide a styrenic resin composition having excellent strength, transparency and moldability. CONSTITUTION:The styrenic resin composition is produced by adding a terpenic resin to a rubber-modified styrenic resin containing a rubbery elastomer as dispersed particles and a continuous phase consisting of a styrenic monomer and an acrylic (or methacrylic) acid ester monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel styrene resin composition containing a terpene resin in a rubber-modified styrene resin. More specifically, the present invention is obtained from the above novel styrene-based resin composition, which shortens the vacuum cycleability, the molding cycle at the time of pressure molding, and enhances the toughness so that the die cracks during trimming of the molded article. A novel styrene-based resin sheet and a biaxially stretched styrene-based resin sheet with excellent transparency, which are provided with prevention;
It is intended to provide a novel styrene resin molded article which is obtained by molding the above novel styrene resin composition and has excellent transparency and strength.

[0002]

2. Description of the Related Art Styrene resins have been widely used as molding materials for household products, electric appliances, etc. since they are excellent in transparency, moldability and rigidity.
As the fields of use have expanded, there has been a strong demand for improved strength and moldability of styrene resins.

It is a known fact that the average molecular weight should be increased to obtain a styrene resin having high strength. However, increasing the average molecular weight inevitably results in a decrease in moldability. Although the use of a plasticizer to supplement the moldability is a known method, the addition of the plasticizer lowers heat resistance and rigidity, and also lowers strength.
In some fields, high-speed molding is desired in order to improve the productivity of products, and it cannot be dealt with only by increasing the molecular weight and improving strength and moldability by using a plasticizer.

Further, in a styrene resin to which a plasticizer such as white mineral oil is added, the plasticizer bleeds out during molding,
It is a well-known fact that it causes a sweating phenomenon, which lowers the productivity and the quality of molded products. On the other hand, a styrene resin obtained by copolymerizing a comonomer such as butyl acrylate is also known. Although the drawbacks of the styrenic resin to which the white mineral oil is added are improved, the strength is greatly reduced. A styrene-based resin obtained by copolymerizing methyl methacrylate is also known, but the good moldability, which is a characteristic of the styrene-based resin, is sacrificed.

[0005]

As described above, in order to improve the strength of the styrene resin, there is a styrene polymer containing a rubber-like elastic material as dispersed particles, that is, a rubber-reinforced styrene resin (HIPS). But this resin is a sheet,
It is opaque even when formed into a film, and cannot be used in fields requiring transparency. Further, it has a defect that the strength, particularly the folding endurance strength, is weak.

Sheets and films of vinyl chloride resin are often used for food packaging and packaging applications. Vinyl chloride resin sheets and films have good moldability and excellent strength of molded products, but due to recent environmental problems, vinyl chloride resin substitute resins have been demanded. Although various improvements have been made to styrene resins consisting of styrene monomers alone, they have not yet been able to satisfy market demands.

On the other hand, a styrene resin obtained by blending polystyrene and a styrene-butadiene block copolymer satisfies the market demand, and is therefore widely used in the market. However, this styrene-based resin has a drawback that the direction dependence of the strength with respect to the orientation during molding is very large. In addition, the molded product has a drawback that the surface of the molded product is easily damaged due to its soft surface and that it is very brittle against salad oil. Further, since a sheet, a film or the like is reworked, the styrene-butadiene block copolymer is cross-linked to form a so-called gel substance, which has a drawback that the surface characteristics of the sheet or the film are significantly deteriorated. And there are problems in fields where strict transparency is required.

As long as polystyrene is used, moldability,
There are limits to strength and surface characteristics. In order to break this limit, by blending a resin containing a second monomer copolymerizable with a styrene-based monomer and a rubber-like elastic body, for example, a styrene-butadiene block copolymer, Although it is expected that the requirements can be satisfied, the strength is actually lower than that of a blend of polystyrene and a rubber-like elastic material, which is not practical. And the styrene-
It has similar drawbacks due to the butadiene block copolymer.

JP-A-62-169812 describes a method of polymerizing a mixed solution of styrene, butyl acrylate, methyl methacrylate and a styrene-butadiene block copolymer. However, the thermoplastic resin polymerized by such a method is transparent and shows a high elongation, but the effect of rubber reinforcement is not recognized at all as seen in the Izod impact strength. That is, the transparency and the elongation are improved, but the strength is not improved.

Conventional styrene-based resin sheets obtained by molding these styrene-based resins are widely used in food packaging containers and the like because of their excellent rigidity, transparency and moldability. Styrenic resin sheets are thermoformed into various containers by vacuum forming machines and pressure forming machines, but shortening the molding cycle during thermoforming improves productivity, so there is a demand for styrene resin sheets that can be shortened. There is. Further, there is a demand for a styrene-based resin sheet that does not cause trouble such as cracking of the molded product when the molded products are stacked and trimmed, and the surface of the molded product is not easily scratched.

As described above, the existing styrene-based resin sheet using the styrene-based resin has not satisfied this market demand. On the other hand, as a food storage container, a hard vinyl chloride resin sheet is often used, and due to recent environmental problems, an alternative resin is required, but there is no one that can be molded under the same conditions as the hard vinyl chloride resin sheet. The current situation.

Since styrene resins are inexpensive and have excellent transparency, moldability, and rigidity, molded products obtained by molding these styrene resins are audio cassette halves and plastics containing cassette halves. Audio products such as cases, office supplies such as trays for storing documents, fish bowls, trays for storing clothes, bird cages, daily miscellaneous goods such as beverage cups, etc. are used in a wide variety of applications. Therefore, the required performance for molded products is becoming more sophisticated. For example, in the case of cassette halves and plastic cases, measures to reduce costs by requesting cost reduction, shortening the molding cycle as much as possible to improve productivity, and reducing the thickness of molded products to the utmost limit are being considered. Therefore, it is required to improve the strength of the styrene resin molding. The trays of the storage boxes are also oriented toward increasing size,
In order to cope with this, it is required to improve the strength of the molded body. Further, it is also required to improve the surface characteristics (hardness to scratches) of the molded product.

Up to now, the above-mentioned styrene resin has been used in order to obtain a molded product having high strength, but it is the current situation that it has not satisfied the market demand.

[0014]

Means for Solving the Problems In view of the present situation, the present inventors have made earnest studies, and as a result, introduced an acrylic acid (methacrylic acid) ester copolymerizable with a styrene monomer,
By adding a terpene-based resin composed of an aromatic vinyl hydrocarbon and a terpene to a styrene-based resin in which a polymer composed of these monomers is used as a continuous phase and a rubber-like elastic material is dispersed as a disperse phase, moldability, strength and rigidity can be improved. A styrene resin composition having an excellent balance of transparency can be obtained, and a sheet or film molded from this styrene resin composition can be molded at a low temperature, and the strength of the molded product is excellent. In addition to shortening the molding cycle at the time of secondary heat molding, it is possible to obtain a styrene-based resin sheet having excellent transparency and surface characteristics, in which the toughness is increased to prevent cracking during molding trimming. And transparency,
The inventors have found that a styrene resin molded product having excellent strength and surface characteristics can be obtained, and completed the present invention.

That is, according to the present invention, a rubber-like elastic material is contained as dispersed particles, and the continuous phase comprises 20 to 20 styrenic monomers.
A styrene-based resin composition comprising 80 parts by weight and a rubber-modified styrene-based resin consisting of 20 to 80 parts by weight of an acrylic acid (methacrylic acid) ester monomer and a terpene-based resin.

The present invention also includes the following embodiments. A styrene resin sheet comprising the styrene resin composition. A styrene-based resin molded product comprising the styrene-based resin composition. Hereinafter, the present invention will be described in detail. The amount of styrenic monomer forming the continuous phase is 20 to 80% by weight, preferably 30.
Is about 70% by weight. If it is less than 20% by weight, the amount of moisture absorbed is large, a drying step is required at the time of molding, and productivity is significantly deteriorated, which is not preferable. Also, 80% by weight
If it exceeds, it is not preferable because a resin excellent in balance of high transparency, strength and moldability cannot be obtained. Also, strength improvement,
It is not preferable because the effect of improving the surface characteristics (hardness to scratches) becomes small and the cost also increases.

The proportions of the styrene monomer and the acrylic acid (methacrylic acid) ester monomer are set so that the refractive index of the continuous phase matches the refractive index of the rubber-like elastic body used. For applications requiring high transparency, it is preferable to control the difference in refractive index between the continuous phase and the rubber-like elastic body to be within 0.010, preferably within 0.008. For applications that do not require transparency, it is not necessary to consider the difference in refractive index.

The degree of polymerization of the continuous phase of the styrenic resin of the present invention is not particularly limited, but at 25 ° C. in consideration of the shape of the styrenic resin composition, sheet, film, molded product, purpose of use and the like. The viscosity of the 10% by weight toluene solution can be set in the range of 15 to 80 centipoise, more preferably in the range of 20 to 70 centipoise.

The total amount of unreacted styrene monomer, acrylic acid (methacrylic acid) ester monomer, and polymerization solvent in the styrene resin of the present invention is 0.15% by weight or less, preferably 0.10% by weight. It is the following. If it exceeds 0.15% by weight, it is not preferable for food hygiene. The total amount of dimers and trimers produced from these monomers is 0.8% by weight or less, preferably 0.6% by weight or less. In the present invention, when the amount exceeds 0.8% by weight, it causes a mold sweat phenomenon at the time of forming a sheet or a molded body, impairs the appearance of a molded product, and causes a decrease in productivity. As such, styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene and the like are used. They may be used alone or as a mixture of them.

In the present invention, as the acrylic acid (methacrylic acid) ester monomer, butyl acrylate, ethyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like are used. When used as a sheet or a film, butyl acrylate and methyl methacrylate are preferably used, and the butyl acrylate content in the continuous phase is preferably 3 to 20% by weight for improving moldability.

When used in a molded product, the content of butyl acrylate and butyl methacrylate in the continuous phase is 0% by weight to 10% by weight depending on the heat resistance required of the molded product.
It is preferable to use in the range of. At this time, methyl methacrylate or butyl methacrylate is preferably used as the acrylic acid (methacrylic acid) ester monomer used in combination.

The rubber-like elastic material of the present invention may be any one that exhibits rubber-like properties at room temperature, and examples thereof include polybutadienes, styrene-butadiene copolymers and styrene-
Butadiene block copolymers are used. More preferred are styrene-butadiene copolymers and styrene-
Butadiene block copolymers. Particularly, those having a styrene content of 10% by weight to 45% by weight are preferable.
Further, the molecular weight and the degree of branching of the rubber-like elastic material are not particularly limited.

The particle size of the dispersed phase of the present invention is from 0.1 μm to
The thickness is 2.0 μm, preferably 0.1 μm to 1.5 μm. If it is less than 0.1 μm, the effect of strengthening the strength is not exhibited,
On the other hand, when it exceeds 2.0 μm, the appearance of the sheet surface and the surface of the molded product is deteriorated, which is not preferable. The particle size referred to in the present invention means the number average particle size observed with a transmission electron microscope unless otherwise specified. The particle size distribution state is not particularly limited, but the following two types are preferable. One is a distribution state in which the particle size distribution (weight average particle size / number average particle size) is 3 or less, and the other is a distribution state having a bimodal distribution. At this time,
The distribution of each of the large and small particle diameters is preferably 2 or less. In addition,
The total average particle size is controlled to be in the range of 0.1 μm to 2.0 μm.

The amount of the rubber-like elastic material in the styrene resin of the present invention is 1 to 20% by weight. It is preferably 3 to 15% by weight. If it is less than 1% by weight, even if a terpene-based resin is added, the effect of reinforcing the strength will not be exhibited, and if it exceeds 20% by weight, the rigidity will be lowered and the usage will be greatly restricted. . In order to obtain the rubber-modified styrenic resin of the present invention, a method often used in the production of rubber-reinforced polystyrene (HIPS resin) can be used.

That is, the rubber-like elastic material was dissolved in a raw material solution containing a styrene-based monomer or an acrylic acid (methacrylic acid) ester-based monomer, a polymerization solvent or a polymerization initiator, and the rubber-like elastic material was dissolved. The raw material solution is supplied to a reactor equipped with a stirrer to carry out polymerization. The particle size of the dispersed particles is controlled by a commonly used method, by changing the stirring number. Also, as a method of maintaining transparency,
A general method is used, for example, a method in which a monomer is added during the polymerization, if necessary, or a method in which additional monomers are continuously added is used.

The content of the rubber-like elastic material can be achieved by adjusting the raw materials and the polymerization rate so as to reach the target content, but a rubber-modified styrene-based material containing a high concentration of the rubber-like elastic material. It can also be achieved by producing the resin by the above method and mixing with a separately produced styrene resin which does not contain a rubber-like elastic material. However, it goes without saying that all the constituent requirements of the present invention are satisfied.

At this time, a polymerization solvent such as ethylbenzene, toluene or xylene can be used.
Further, an organic peroxide often used for the polymerization of styrene-based polymers may be used or may be added midway. The polymerization method is a bulk polymerization method that is commonly used in the production of styrene-based polymers,
Alternatively, a solution polymerization method is used. Either a batch polymerization method or a continuous polymerization method can be used.

The polymerization solution that has left the reactor is guided to a recovery device. As the recovery device, a device commonly used in the production of styrene-based resins, for example, a flash tank system, an extruder with a multistage vent, or the like can be used. The operating conditions may be the same as those used for producing the styrene resin. In the present invention, the terpene resin is a Friedel-Crafts-type catalyst (for example, di-pentene and aromatic hydrocarbon obtained by isomerization of d-limonene obtained from citrus cortex or α-pinene obtained from raw pine resin). It can be obtained by carrying out cationic polymerization using aluminum chloride or boron trifluoride).
Styrene, vinyltoluene and the like are preferably used as the aromatic hydrocarbon.

The degree of polymerization of the copolymer is not particularly limited, but the degree of polymerization is 500 or less, preferably 200 or less, more preferably 100 or less. When the degree of polymerization exceeds 500, the compatibility with the rubber-modified styrene-based resin decreases, and as a result, the transparency decreases, which is not preferable. As a terpene resin,
For example, YS Hara Chemical Co., Ltd. YS resin TO-
125, TO-115, TO-105, TO-85, etc. can be used.

The terpene-based resin may be added by dissolving in a styrene-based monomer or a mixture of a styrene-based monomer and an acrylic acid (methacrylic acid) ester monomer and polymerizing, or by polymerizing a styrene-based polymer. A method in which the terpene-based resin is added in the middle of melting or dissolved in the solvent, or the terpene-based resin is added before or after the unreacted monomer and the solvent are removed after the polymerization is completed is used. be able to. Alternatively, a styrene resin and a terpene resin may be mixed and kneaded with an extruder, a molding machine, or the like.

The mixing ratio of the styrene resin and the terpene resin is 0.5 to 30 parts by weight, more preferably 1 to 2 parts by weight per 100 parts by weight of the rubber-modified styrene resin.
The amount is 0 parts by weight, more preferably 1 to 15 parts by weight. If it is less than 0.5 parts by weight, the effect of improving strength and moldability is not recognized, and if it exceeds 30 parts by weight, the rigidity is lowered and the cost of the resin composition is increased, which is not preferable.

In the present invention, the rubber-modified styrene-based resin and the terpene-based resin are mixed at any stage before or after collecting the unreacted monomer and / or the polymerization solution during the production of the rubber-modified styrene-based resin. In the step of molding, or the step of extruding or molding the styrene resin composition, additives commonly used in styrene resins, such as antioxidants, lubricants, plasticizers, colorants, antistatic agents, etc., can be added. .

The styrenic resin composition thus obtained can be prepared by various known methods generally used for molding thermoplastic resins, for example, injection molding, extrusion molding, compression molding and the like. Molded into a molded body. Further, in the present invention, after being formed into a film, a biaxially stretched film, a sheet or the like, it can be formed into a desired formed body. Further, an antistatic agent and a lubricant such as silicone may be applied to the surface of the obtained styrenic resin molded article, particularly a film or a sheet, in order to improve the surface characteristics.

It is also possible to mix and use the specific styrenic resin composition used in the present invention with other styrenic resins and the like within a range not impairing the intended purpose of the present invention. <Styrene-based resin sheet> To prepare the styrene-based resin sheet according to the present invention, a general method that has been widely used in the past, for example, a method of melting from an extruder and then extruding from a T-die is used. . The thickness of the sheet is not particularly limited, but a thickness in the range of 0.05 to 2 mm is preferably used.

Further, the sheet molded by the above method can be preferably used as a biaxially stretched styrene resin sheet having a stretching ratio of 2 to 5 by employing a generally known tenter system, inflation system or the like. Can be done. The styrene-based resin sheet according to the present invention has good moldability, and vacuum molding,
Alternatively, by a conventionally used molding method such as hot plate pressure molding (contact heating pressure molding) or indirect heating pressure molding, the molding cycle can be shortened when molding a lightweight container, a lid or the like.

The styrene-based resin sheet of the present invention has a high sheet strength and does not cause cracking of the molded product during trimming. Further, since the strength of the molded product is improved, it is possible to make the thickness thinner than the conventional molded product. Further, since the styrene resin composition of the present invention has a good elongation at the time of molding, it can be molded at a lower temperature than conventional styrene resins. The heating time of the sheet is shortened, and as a result, the molding cycle can be shortened.

In obtaining the styrene resin sheet, a plasticizer, a lubricant, a pigment, an antistatic agent, a flame retardant and the like may be mixed and used. Also, the surface of the obtained styrene resin sheet,
Alternatively, an antistatic agent, silicone, antibacterial agent or the like may be applied to the surface of the sheet molded article. The specific styrene resin composition used in the present invention may be mixed with another styrene resin within a range not impairing the function of the styrene resin sheet intended in the present invention. <Styrene-based resin molded product> The styrene-based resin molded product of the present invention is characterized by being excellent in strength. The shape of the molded body is not particularly limited, but the styrene-based resin composition of the present invention has an excellent balance between fluidity and strength, so that it is a large molded product, for example, a storage tray for office equipment, a paper storage tray, Copy paper tray, fishbowl, bird cage, breeding box,
It is optimally used for costume cases, audio product storage cases, toys, computer tape storage equipment, food storage cases, electric refrigerator crispers, office machine parts, audio equipment parts, cosmetics storage cases, etc. It is also suitably used for a storage medium storage container, for example, a storage container for audio tape / video tape, a storage case for an audio cassette, a video cassette tape, an audio disc, a video disc, a floppy disc, or the like. It can also be used for housings of thin products, video cassette tapes, audio tapes and the like.

In the present invention, 10 is a measure of the degree of polymerization.
The viscosity of the wt% toluene solution is measured using an Ostwald Cannon-Fenske viscous tube # 350 in a thermostat at 25 ° C. The particle size of the dispersed particles was determined by the following formula by taking a magnifying power of 10,000 times in a transmission electron microscope photograph by a resin ultra-thin section method, measuring the number of dispersed particles in the photograph of about 1000 to 2000, It is a thing.

Particle size of dispersed particles = ΣDi / n Di =
i-th particle diameter n = number of measured particles Since the dispersed particles shown in the electron micrograph are not perfectly circular, the particle diameter is measured by measuring the long axis (a) and the short axis (b) of the particles. It is calculated by the following formula using the measured value of the height.

Particle size = (a + b) / 2 The amount of the rubber-like elastic material in the styrene resin is measured by an infrared absorption spectrum method which is generally used for rubber-reinforced polystyrene.

[0041]

EXAMPLES The present invention will be described in more detail below. However,
The invention is in no way limited by these examples. (Production of rubber-modified styrene resin-1) 31 parts by weight of styrene, 9.3 parts by weight of butyl acrylate, 36.7 parts by weight of methyl methacrylate were added to a reactor equipped with a stirrer.
Charge 15 parts by weight of ethylbenzene, and add 8 parts by weight of Sorprene 308 (styrene-butadiene block copolymer having a styrene content of 30%) manufactured by Asahi Kasei Corporation.
After the rubber-like elastic material has dissolved, 0.03 part by weight of organic peroxide Perhexa C from NOF CORPORATION is charged and the temperature is 120 ° C.
2 hours, 135 ° C. for 2 hours, and 145 ° C. for 2 hours. After completion of the polymerization, the reaction solution was introduced into a twin-screw extruder with a two-stage vent to remove unreacted monomers and the polymerization solution and pelletized. (Production of Rubber Modified Styrene Resin-2) 30 parts by weight of styrene, 9.2 parts by weight of butyl acrylate, 37.8 parts by weight of methyl methacrylate, Tafden 2000 manufactured by Asahi Kasei Corporation (styrene-butadiene block containing 25% styrene). (Copolymer) Except for 8 parts by weight, the same operation as in the rubber-modified styrene resin-1 was carried out to obtain a rubber-modified styrene resin-2. (Production of Rubber Modified Styrene Resin-3) Styrene 39.
Rubber-modified styrenic resin-1 was operated in the same manner as rubber-modified styrene-based resin-1, except that 3 parts by weight, 37.7 parts by weight of methyl methacrylate, and 8 parts by weight of Sorprene 308 were used.
Got 3. (Production of Rubber Modified Styrene Resin-4) Rubber Modified Styrene Resin-1 except 40 parts by weight of styrene, 4.8 parts by weight of butyl acrylate, 32.2 parts by weight of methyl methacrylate and 8 parts by weight of Sorprene 308. The same operation was performed to obtain rubber-modified styrene resin-4. (Production of Rubber Modified Styrene Resin-5) 50 parts by weight of styrene, 27 parts by weight of methyl methacrylate, Sorprene 3
08 except 8 parts by weight except rubber-modified styrene resin-
The same operation as in 1 was carried out to obtain a rubber-modified styrene resin-5. (Production of Rubber Modified Styrene Resin-6) Rubber Modified Styrene Resin-1 except that 51 parts by weight of styrene, 4.8 parts by weight of butyl acrylate, 21.2 parts by weight of methyl methacrylate, and 8 parts by weight of Sorprene 308. The same operation was performed to obtain a rubber-modified styrene resin-6. (Production of Rubber-Modified Styrene Resin-7) The procedure of Rubber-Modified Styrene Resin-1 was repeated except that 77 parts by weight of styrene, 0 parts by weight of butyl acrylate, 0 parts by weight of methyl methacrylate, and 8 parts by weight of Sorprene 308 were used. A rubber-modified styrene resin-7 was obtained.

The resin compositions of the rubber-modified styrene resins-1 to 7 are shown in Table 1.

[0043]

[Table 1]

[0044]

Example 1 100 parts by weight of rubber-modified styrene resin-1 and 2 parts by weight of terpene resin YS resin TO-115 of Yasuhara Chemical Co., Ltd. were pellet blended and granulated with a twin-screw extruder to obtain styrene resin. Composition-1 was obtained.
The physical property values are shown in Table 2.

[0045]

Example 2 100 parts by weight of rubber-modified styrene-based resin-1 and 5 parts by weight of terpene-based resin YS resin TO-115 from Yasuhara Chemical Co., Ltd. were pellet-blended and granulated with a twin-screw extruder to obtain styrene-based resin. Composition-2 was obtained.
The physical property values are shown in Table 2.

[0046]

Example 3 100 parts by weight of rubber-modified styrene resin-1 and 10 parts by weight of terpene resin YS resin TO-115 of Yasuhara Chemical Co., Ltd. were pellet blended,
The mixture was granulated with a twin-screw extruder to obtain a styrene resin composition-3. The physical property values are shown in Table 2.

[0047]

[Example 4] 100 parts by weight of rubber-modified styrene resin-1 and 15 parts by weight of terpene resin YS resin TO-115 from Yasuhara Chemical Co., Ltd. were pellet blended,
The mixture was granulated with a twin-screw extruder to obtain a styrene resin composition-3. The physical property values are shown in Table 2.

[0048]

Example 5 100 parts by weight of rubber-modified styrene-based resin-2 and 5 parts by weight of terpene-based resin YS resin TO-115 from Yasuhara Chemical Co., Ltd. were pellet-blended, granulated by a twin-screw extruder, and styrene-based resin. Composition-4 was obtained.
The physical property values are shown in Table 2.

[0049]

Example 6 100 parts by weight of rubber-modified styrene-based resin-3, 5 parts by weight of terpene-based resin YS resin TO-115 of Yasuhara Chemical Co., Ltd. were pellet blended, granulated by a twin-screw extruder, and styrene-based resin. Composition-5 was obtained.
The physical property values are shown in Table 2.

[0050]

[Example 7] 100 parts by weight of rubber-modified styrene-based resin-4, 5 parts by weight of terpene-based resin YS resin TO-115 of Yasuhara Chemical Co., Ltd. were pellet-blended, granulated by a twin-screw extruder, and styrene-based resin. Composition-6 was obtained.
The physical property values are shown in Table 2.

[0051]

[Example 8] 100 parts by weight of rubber-modified styrene resin-5 and 5 parts by weight of terpene resin YS resin TO-115 of Yasuhara Chemical Co., Ltd. were pellet-blended and granulated with a twin-screw extruder to obtain styrene resin. Composition-7 was obtained.
The physical property values are shown in Table 2.

[0052]

[Example 9] 100 parts by weight of rubber-modified styrene resin-6, 5 parts by weight of terpene resin YS resin TO-115 from Yasuhara Chemical Co., Ltd. were pellet blended, granulated by a twin-screw extruder, and styrene resin was added. Composition-8 was obtained.
The physical property values are shown in Table 2.

[0053]

Comparative Example 1 Physical properties were measured using a rubber-modified styrene resin-1. The physical property values are shown in Table 2.

[0054]

Comparative Example 2 Physical properties were measured using a rubber-modified styrene resin-2. The physical property values are shown in Table 2.

[0055]

Comparative Example 3 Physical properties were measured using a rubber-modified styrene resin-3. The physical property values are shown in Table 2.

[0056]

[Comparative Example 4] Physical properties were measured using a rubber-modified styrene resin-4. The physical property values are shown in Table 2.

[0057]

Comparative Example 5 Physical properties were measured using a rubber-modified styrene resin-5. The physical property values are shown in Table 2.

[0058]

Comparative Example 6 Physical properties were measured using a rubber-modified styrene resin-6. The physical property values are shown in Table 2.

[0059]

[Comparative Example 7] 100 parts by weight of rubber-modified styrene resin-7, 5 parts by weight of terpene resin YS resin TO-115 from Yasuhara Chemical Co., Ltd. were pellet blended, granulated by a twin-screw extruder, and styrene resin. Composition-7 was obtained.
The physical property values are shown in Table 2.

[0060]

Comparative Example 8 100 parts by weight of rubber-modified styrenic resin-7 and 2 parts by weight of mineral oil were blended, granulated with a twin-screw extruder and pelletized. The physical property values are shown in Table 2.

[0061]

[Reference Example] Rubber-modified styrene resin-7 was used to measure the physical properties. The physical property values are shown in Table 2. The physical properties were measured based on the following methods. (1) MFR: According to ISO R1133. (2) VICAT: According to ASTM D1525. (3) Tensile strength: According to ASTM D623. (4) Izod impact strength: According to ASTM D256. (5) Impact strength per shot: 5 cm x 8.8 cm by injection molding machine
A test piece of × 2 mm is molded, and a height of 20 c is obtained by using a “falling weight type graphic impact tester” manufactured by Toyo Seiki Seisakusho.
The maximum load (N: Newton) at the time of destruction is determined by allowing a missile with a mass of 6.5 kg to fall naturally from m.

[0062]

[Table 2]

It can be understood that the styrene resin composition of the present invention has a markedly improved strength, and in particular, the impact strength, which is a substantial strength. If the acrylic acid (methacrylic acid) ester monomer is not contained, even if the terpene resin is added, the improvement of the single impact strength is not recognized. Further, by adding the terpene resin, it is possible to improve the fluidity without substantially lowering the heat resistance. Addition of mineral oil, which has been generally used in the past, causes a large decrease in heat resistance, and also a reduction in the practical impact strength of one-shot impact.

It should be noted that, except for Examples 8 and 9, it is transparent, but Examples 8 and 9 are slightly cloudy, and cannot be used in applications requiring high transparency. However, although Comparative Examples 7 and 8 are completely opaque, Examples 8 and 9 show transparency when brought into contact with water or the like, and thus are suitable for beverage containers and the like whose contents are required to be visible. It can be used sufficiently. <Styrene resin sheet>

[0065]

Example 9 Using the styrene resin composition used in Example 2, a sheet having a thickness of 0.30 mm was prepared with a 30 mm extruder. The physical properties of this sheet are shown in Table 3. This sheet was thermoformed using a hot plate pressure air forming machine. Heating the sheet at a heating pressure 1.0 kg / cm ^2, molding pressure 2.5 kg / cm ^2, molding time 2 seconds, and molded under the conditions of mold temperature 60 ° C., the hinge 3R mold (Food Pack) The heating time and the physical properties at a hot plate temperature of 110 ° C. and 120 ° C. that can be reproduced as a mold were determined. The results are shown in Table 3.

[0066]

Example 10 Using the styrene resin composition used in Example 5, the same evaluation as in Example 9 was performed. The results are shown in Table 3.

[0067]

Example 11 Using the styrene resin composition used in Example 7, the same evaluation as in Example 9 was performed. The results are shown in Table 3.

[0068]

Comparative Example 9 The same evaluation as in Example 9 was performed using the styrene resin composition used in Comparative Example 1. The results are shown in Table 3.
Shown in.

[0069]

Comparative Example 10 Using the styrene resin composition used in Comparative Example 2, the same evaluation as in Example 9 was performed. The results are shown in Table 3.

[0070]

Comparative Example 11 The same evaluation as in Example 9 was carried out using the styrene resin composition used in Comparative Example 4. The results are shown in Table 3.

[0071]

Comparative Example 12 Using the styrene resin composition used in Comparative Example 8, the same evaluation as in Example 9 was performed. The results are shown in Table 3.

[0072]

Comparative Example 13 50 parts by weight of Asahi Kasei Polystyrene 666, Asaflex 810, 50 manufactured by Asahi Kasei Corporation
Part by weight was blended and granulated with a twin-screw extruder to obtain pellets. The same evaluation as in Example 9 was performed using this pellet. The results are shown in Table 3.

[0073]

[Table 3]

The physical properties were measured by the following methods. (1) Impact strength per shot: A sample of 5 cm × 8.8 cm is cut out from the sheet and measured in the same manner as the injection-molded product in Table 2. (2) Transparency: Judged with the naked eye. "Blueness" of Comparative Example 13
Means the color tone of the sheet. All others are colorless.

◎: transparent ○ to △: slightly cloudy ×: opaque The styrene-based resin sheet of the present invention is significantly improved in transparency and strength as compared with the conventional styrene-based resin sheet (transparent polystyrene / thermoplastic elastomer mixture sheet). I can understand that. It can also be understood that the sheet strength is remarkably improved by adding the terpene resin.

The styrene resin sheet of the present invention can shorten the heating time as compared with the conventional styrene resin sheet. or,
The styrene-based resin sheet of the present invention to which the terpene-based resin is added can shorten the heating time as compared with the resin sheet to which the terpene-based resin is not added. That is, it can be understood that the styrene resin sheet of the present invention can shorten the molding cycle and improve the productivity. <Styrene resin molding>

[0077]

Example 12 Using the styrene resin composition used in Example 2, an injection molding machine IS800B-75 (manufactured by Toshiba Machine Co., Ltd.) was used and an injection pressure was 100 kg / cm ² and a mold temperature was 60 ° C. Under the conditions of, the tray shown in FIG. 1 was molded. At this time, the molding temperature was changed to determine the minimum molding temperature at which the tray could be molded. Next, 40g in the center of this tray
The steel ball was dropped, the height at which cracking occurred was measured, and the breaking energy was obtained. In addition, the obtained molded product was visually evaluated for transparency. The results are shown in Table 4.

Further, the tray was molded under the same conditions except that the molding temperature was 250 ° C., and the number of injections until the sweating substance was transferred to the surface of the molded product (the occurrence of mesiness) was determined. The results are shown in Table 4.

[0079]

Example 13 Using the styrene resin composition used in Example 6, the same evaluation as in Example 12 was performed. The results are shown in Table 4.

[0080]

Example 14 Using the styrene resin composition used in Example 7, the same evaluation as in Example 12 was performed. The results are shown in Table 4.

[0081]

Comparative Example 14 Using the styrene resin composition used in Comparative Example 1, the same evaluation as in Example 12 was performed. The results are shown in Table 4.

[0082]

Comparative Example 15 Using the styrene resin composition used in Comparative Example 3, the same evaluation as in Example 12 was performed. The results are shown in Table 4.

[0083]

Comparative Example 16 The same evaluation as in Example 12 was performed using the styrene resin composition used in Comparative Example 8. The results are shown in Table 4.

[0084]

Comparative Example 17 Using the styrene resin composition used in Comparative Example 13, the same evaluation as in Example 12 was performed. The results are shown in Table 4.

[0085]

[Table 4]

The styrene resin molding of the present invention is transparent,
It can be seen that the strength is excellent. It can be understood that the transparency is improved and the strength is also improved as compared with the conventional strength-improved product of transparent polystyrene (thermoplastic elastomer blend type). Further, it can be understood that the addition of the terpene resin of the present invention improves the moldability and the strength of the molded product.

The generation of sweating substances due to the conventionally used mineral oil is not found in the styrene resin composition of the present invention containing a terpene resin.

[0088]

[Effects of the Invention] A rubber-modified styrene resin containing a styrene polymer composed of a styrene monomer and an acrylic acid (methacrylic acid) ester monomer as a continuous phase and a rubber-like elastic body as a dispersed phase, and a terpene resin. By containing a styrene-based resin composition having excellent strength, transparency, and low-temperature moldability (shortening molding cycle), (reducing transparency for applications that do not require high transparency) A styrene-based resin composition obtained by molding the styrene-based resin composition can be secondary-molded at a low temperature, and the molding cycle can be shortened. By giving a sheet, a styrene-based resin molded article obtained by molding a styrene-based resin composition and having excellent strength and transparency is provided.

[Brief description of drawings]

1 is a diagram of the manufactured tray of Example 12 of the present invention. FIG.

Claims (3)

[Claims] 1. A rubber-like elastic material is contained as dispersed particles,
Styrene characterized in that the continuous phase is composed of a rubber-modified styrene resin and a terpene resin, the styrene monomer being 20 to 80 parts by weight and the acrylic acid (methacrylic acid) ester monomer being 20 to 80 parts by weight. -Based resin composition. 2. A styrene resin sheet comprising the styrene resin composition according to claim 1. 3. A styrene-based resin molded product comprising the styrene-based resin composition according to claim 1.