JPS602473A - Tape cassette vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention relates to a container for storing tape cassettes containing magnetic tape, such as ICRO cassettes, compact cassettes, and VTR cassettes.

More specifically, the present invention relates to a tape cassette container made of a specific styrene resin composition and having excellent strength and appearance.

The tape cassette container is required to have the following characteristics.

In other words, (1) If you accidentally drop it on the floor or hit it against something with all the tape cassettes stored inside,
(2) The container must not be contaminated with oil and adhere to the magnetic tape from the cassette opening, or the beauty of the container may be lost. It is necessary that the Such tape cassette containers have conventionally been manufactured by injection molding using materials such as polystyrene and rubber-reinforced polystyrene, but these conventional materials have advantages and disadvantages.

That is, although rubber-reinforced polystyrene has high drop strength, it has a drawback of low surface hardness and being easily damaged. In addition, the polystyrene traditionally used has low drop strength,
There was a drawback that the index card placed inside the container was contaminated with the oil that had bleed out, reducing the product value.

As a result of intensive research to overcome these drawbacks of the prior art, the present inventor has developed a material using a styrenic resin composition containing a styrene polymer having a specific molecular weight and a white mineral oil having a specific initial boiling temperature. By doing so, it was discovered that all the drawbacks of conventional tape cassettes could be overcome, and the present invention was completed. - In other words, the present invention provides a styrene-based polymer having an intrinsic viscosity (hereinafter referred to as "intrinsic viscosity") of 0.7 to 1.1 in toluene at 30°C, with an initial boiling temperature of 200°C under a reduced pressure of 10mmHg. White mineral oil whose temperature is above ℃
This invention relates to a tape cassette container characterized by being made of a styrene resin composition containing 0.1 to 10 parts by weight.

In the present invention, the styrenic polymer includes not only a polymer obtained by polymerizing a styrene monomer, but also a copolymer containing a styrene monomer as a main component and other copolymerizable vinyl monomers. include. Here, the styrenic monomers are styrene,
Refers to one or more types of nuclear substituted styrenes such as α-methylstyrene, tertiary-butylstyrene, and p-methylstyrene.

It needs to be in the range of 0.7 to 1.1, preferably in the range of 0.8 to 1.0. If the intrinsic viscosity is less than 0.7, the strength will be weak and cause breakage. ], if it exceeds 1, the moldability will be relatively low and molding distortion will remain, resulting in poor practical heat resistance such as when placed in a car in the summer and causing deformation.
I don't like it.

In the styrenic resin composition that is the material for the cassette container of the present invention, the content of white mineral oil whose initial boiling temperature under IornTnHg reduced H- is 200°C or higher is based on 100 parts by weight of the styrenic polymer. 0.1 to 10 parts by weight,
A suitable amount is 0.5 to 6.5 parts by weight. If it is less than 0.1 part by weight, the container will not easily slip, and the entry card will not be inserted smoothly. do not have.

This white mineral oil must have an initial distillation temperature of 200° C. or higher; if a white mineral oil with an initial distillation temperature lower than 200° C. is used, the mineral oil will ooze out of the product container, reducing the commercial value.

Methods for producing this styrenic resin composition include a mechanical mixing method such as kneading white mineral oil into a styrenic polymer, and a method of mechanical mixing such as kneading white mineral oil into a styrenic polymer. Although there are methods for doing this, it is preferable to use an addition method in which the styrene monomer is mixed in advance with the styrene monomer when the styrenic polymer is impregnated and polymerized.

The method of polymerizing the styrenic polymer is not particularly limited, and bulk, suspension, or bulk-suspension polymerization methods are preferred, but are not limited to these. It is also possible to add all molecular weight regulators such as mercaptans and α-methylstyrene dimer during polymerization.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples. However, the invention is not limited to these examples.

Example] 100 kg of pure water, 32 y of sodium todenlebenzene sulfonate, and 600 y of tertiary calcium phosphate were added to an autoclave with an internal volume of 230 t, and stirred at 150 rpm.

Next, 90 kg of styrene mixed in advance and IOaHg
1.8 kg of white mineral oil with an initial boiling temperature of 264°C under reduced pressure
Then, benzoyl peroxide 1627 and tert-butyl peroxyhenzoate 1362 were added, and the inside of the autoclave was purged with nitrogen gas and then sealed. Thereafter, the temperature was raised, and after the internal temperature reached 90°C, it was maintained for 8 hours, at 115°C for 1 hour, and at 135°C for 2 hours to complete polymerization, and then cooled. Then, according to a specific method, the mixture was neutralized, dehydrated, dried, and extruded to obtain a styrenic resin composition in the form of a normal pellet.

The intrinsic viscosity of this product was 0.96. This resin composition was molded into a cheese cassette container using a 902 in-line screw injection molding machine FS-1703E manufactured by Nissei Resin. The appearance of the container is good, with no oil stains etc. This container was fitted with a commercially available tape cassette and dropped 95 times from a height of 1 meter onto a PVC tile surface, but there was no damage such as a single crack to the container, and there was no change in the tape cassette body inside. was not seen.

Comparative Example 1] A styrenic resin composition was obtained in the same manner as in Example 1, except that white mineral oil having an initial distillation temperature of 178° C. under reduced pressure of OmmHg was used.

The intrinsic viscosity of this product was 0.94. Oil leakage was observed on the tip of the lip and the mating area of the tape container. There was no difference in drop strength from the composition obtained in Example 1.

Comparative Example 2 Example except that the amount of white mineral oil used was 9 for i9.5]
A styrene resin composition was obtained in the same manner as above.

The intrinsic viscosity of this product was 0.91. Oil leakage was observed on the tip of the lip and the mating area of the Cheeve cassette container. There was no difference in drop strength from the composition obtained in Example 1.

Comparative Example 3 270y of benzoyl peroxide and 45Pk of ter/y-phthyl peroxybenzoate were added and heated at 90°C for 5 hours.
A styrenic resin composition was obtained in the same manner as in Example except that the reaction was carried out at 115°C for 1 hour and at 135°C for 1 hour.

The intrinsic viscosity of this product was 0.65. The appearance of the Chive cassette container is good and there are no oil stains or the like. Regarding the drop strength, part of the corner of the container was damaged during the second fall, and cracks were also observed on the ref of the container.

Patent applicant Denki Kagaku Kogyo Co., Ltd. 4C

Claims (1)

[Claims] Intrinsic viscosity at 30'C in toluene is 0.7-1.1
]00 parts by weight of the styrenic polymer, ]OaH
g A tape cassette container made of a styrene resin composition containing 0.1 to 10 heavy parts of white mineral oil having an initial boiling temperature of 200° C. or higher under reduced pressure.