JP2001062828A - Manufacture of plastic molding for emitting fragrance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding made of a homogeneous thermoplastic plastic while maintaining dissipating of fragrance for a long period by incorporating an aromatic in the molding. SOLUTION: A pellet of a thermoplastic plastic such as an ethylene-vinyl acetate copolymer resin (EVA) or the like is mixed with a liquid-like aromatic, and the pellet is impregnated with the aromatic, and thereafter the mixture is molded by a molding machine. The pellet and the aromatic are agitated and mixed in a container, and the container is left to stand while holding the container in a hermetically sealed state to impregnate the pellet with the aromatic, and thereafter the mixture is molded. After the pellet and the aromatic are mixed in a hopper 2 of the molding machine 1, the mixture may be then molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic molded article emitting fragrance. More specifically, the present invention relates to a method for producing a fragrant plastic molded product used for, for example, a key ring, a mobile phone strap, a figurine, a doll, a part of a home appliance, a fragrance accessory, and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a plastic molded article emitting fragrance, after molding using a thermoplastic plastic such as acrylic or vinyl chloride, a fragrance is directly sprayed on the molded article or a liquid fragrance is applied to the molded article. There is known a method of immersion in the inside. However, according to this method, the fragrance is impregnated only near the surface of the molded article, and the scent attached to the molded article is impaired in a short period of time.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. H10-179707, a method has been proposed in which a porous powder carrying a fragrance is mixed into a thermoplastic and injection molding or the like is performed. However, according to this method, since the porous powder is dispersed in the thermoplastic molded article, a problem in appearance and a problem in strength may occur.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, the present invention relates to a molded article made of a homogeneous thermoplastic plastic while containing a fragrance to the inside of the molded article for a long period of time to maintain the emission of fragrance. It is an object of the present invention to provide a method for producing a plastic molded article which emits a fragrance capable of obtaining a fragrance.

[0005]

In order to achieve the above-mentioned object, a feature of the method for producing a plastic molded article emitting fragrance according to the present invention is a method for producing a plastic molded article emitting fragrance, comprising the steps of: It is to mix pellets or powder (hereinafter, referred to as “pellets or the like”) with a liquid fragrance to impregnate the pellets or the like with the liquid fragrance, and then form the mixture with a molding machine.

In particular, it is desirable to use ethylene-vinyl acetate copolymer resin (EVA) as the plastic.

[0007] It has been found that the content ratio of vinyl acetate in the plastic is suitably from 2% to 40% by weight.

Further, the pellets and the like and the liquid fragrance are stirred and mixed in a container, and the container is left in an airtight state to be impregnated with the fragrance and the pellets. May be performed. The leaving time at this time may be about 1 hour to 72 hours.

When it is desired to increase the production speed, the molding may be performed after mixing the pellets and the like and the liquid fragrance with a hopper of the molding machine instead of using a sealed container.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to the attached drawings,
The present invention will be described in more detail. In the present embodiment, pellets of ethylene-vinyl acetate copolymer resin (EVA) are used as the thermoplastic material. This EV
This is because A has a relatively low melting point and excellent gas permeability. This is because, if the gas permeability is excellent, the fragrance contained in the center of the molded product is also effectively radiated to the outside. The gas permeability, the impregnation rate of the liquid fragrance, the melting point of the plastic and the flexibility of the molded article depend on the content of vinyl acetate in the EVA. That is, as the content of vinyl acetate in the EVA increases, the gas permeability increases, the impregnation rate of the liquid fragrance increases, the melting point of the plastic decreases, and the molded product becomes more flexible.

According to the inventor, the content ratio of vinyl acetate in plastic is 2% to 40% by weight.
% Has been found to be appropriate. More desirably, it has been found that it is practically appropriate that the content ratio of vinyl acetate is 20% to 33% by weight. According to this latter weight ratio range, the melting point of the entire EVA is as low as 59 to 83 degrees Celsius, and it is sufficient to increase the temperature only within 20 degrees Celsius during injection molding, and to perform the molding with only increasing the temperature. This is because the volatilization of the compound can be minimized.

On the other hand, as the liquid fragrance, it is desirable to use a material having a high boiling point and excellent retention in plastics. By impregnating a plastic pellet having a low melting point with an aromatic having a high boiling point and molding, it is possible to prevent wasteful evaporation of the aromatic during molding.

In order to sufficiently impregnate the plastic pellets with the fragrance without waste, the following procedure is desirable.

First, about 100 to 500 g of the pellets are divided into nylon or polyethylene bags. Then, 2% or more and 3% by weight of the liquid fragrance, which is the compounded flavor
Inject below and mix them immediately within one minute.
If they are not immediately mixed, the fragrance will be absorbed in a part of the pellets, and the molded article will have uneven scent.

Thereafter, the bags are sealed and left at room temperature for at least 1 hour and up to 72 hours. Immediately after stirring, the fragrance may become droplets and adhere to the inner surface of the bag,
By this sealing, the fragrance in the form of droplets is almost completely absorbed by the plastic pellets. The higher the content of vinyl acetate, the higher the impregnation rate of the liquid fragrance. Therefore, the standing time may be appropriately adjusted depending on the type of the liquid fragrance and the content of vinyl acetate.

Next, the above-mentioned plastic pellets which have been left and impregnated with the fragrance are put into a hopper 2 of an injection molding machine 1 shown in FIG. 1, and an appropriate amount of a pigment or a luminous agent is put in if necessary and stirred. Next, the agitated material is melted via the screw portion 3 whose inside is forcibly rotated by the screw driving portion 4 and injected into the mold 5 to form a molded product.

Incidentally, in order to improve the production speed by omitting the above-mentioned bag-packing step, the liquid fragrance is also directly charged after the plastic pellets are charged into the above-mentioned hopper 2, and the two are stirred by the hopper 2. Is also possible. Then, after the mixture is left for several minutes after the stirring to impregnate the fragrance into the pellets, injection molding may be performed. It should be noted that the practice of this manufacturing method will be limited to the case where the vinyl acetate content is high to some extent, the liquid fragrance is easily impregnated, and a relatively large lot is produced.
If it is difficult to impregnate the fragrance in a small lot, use hopper 2
This is because expensive liquid fragrances remain inside and waste is increased, and the hopper 2 also needs to be cleaned.

Now, embodiments of the present invention will be listed below.

Example 1 In this example, a molded product for a key ring was prepared. Oranges, lavenders and peaches were prepared using the following high-boiling materials as fragrances. EVA having a melting point of 83 degrees Celsius and containing 20% by weight of vinyl acetate was used as the resin pellet.

Raw materials of orange: acetoeugenol, acetoisoeugenol, olivanol, ferrandrin, aliphatic aldehyde, thymol, carvacrol,
Bornyl methkin cyclohexanol Lavender Ingredients: Bornyl methkin cyclohexanol, eugenol, cinnamaldehyde, benzaldaldehyde, californum, coumarin, macrocyclic musk, ethyl crocodile, evelic acid, cinnamic acid, crocodile, guayol, furfural, acetophenone peach Ingredients: gamma undecalactone, benzaldehyde, crocodile, gamma decalactone

First, 500 g of the pellets are stored in separate nylon bags, and then about 16 g of each of the above fragrances.
Each was put into each bag. After the addition of the fragrance, each bag was rubbed by hand, and the pellets and the fragrance were mixed within one minute.

The mixture was allowed to stand at room temperature for 3 days (72 hours), and the inside of the bag was checked. As a result, the fragrance attached to the inside of the bag in the form of droplets was almost completely absorbed by the pellets.
About 0.1 to 0.3% by weight of a pigment was mixed into the pellets and molded by the above-mentioned injection molding machine. The resin temperature of the molding machine was 100 degrees Celsius or less.

[0022] The resulting molded article had a sufficient orange, lavender or peach aroma. The obtained molded article was subjected to an accelerated weathering test for 3 months under an environment of 40 degrees Celsius, but no sharp decrease in scent intensity was observed.

[0023]

Embodiment 2 In the description of the second embodiment and other embodiments, basically the same manufacturing steps as those in the first embodiment are employed, and only different materials and different steps will be described.

In the second embodiment, a molded product for a key holder which is more flexible than in the first embodiment was obtained by using EVA containing 33% by weight of vinyl acetate. In the present example, the pellets impregnated with the fragrance before molding were added with the luminous agent in a weight ratio of 0.5%.
%, And the resin temperature during molding was set to 80 ° C. or less. According to this example, as in the first example, it was possible to obtain a molded article whose fragrance hardly attenuated in the accelerated weathering test.

[0025]

Embodiment 3 In the third embodiment, a molded article which is a harder part of a home appliance than in the first and second embodiments was obtained by using EVA containing 2% by weight of vinyl acetate. According to this example, as in the first and second examples, it was possible to obtain a molded article in which the fragrance was hardly attenuated in the accelerated weathering test and the strength was not reduced. By providing the components of the present embodiment at or near the movable portion, it is possible to make the fragrance drift with each operation.

[0026]

Embodiment 4 In the fourth embodiment, a doll toy softer than in the first to third embodiments was obtained by using EVA containing 40% by weight of vinyl acetate. According to this example, as in the first to third examples, it was possible to obtain a molded article whose fragrance hardly attenuated in the accelerated weathering test.

Finally, the possibility of still another embodiment of the present invention will be listed. In the above embodiment, the case where the injection molding is performed has been described. However, the present invention can be applied not only to injection molding but also to extrusion molding, blow molding and the like.

In the above embodiment, EVA pellets were used as the thermoplastic material. However, in connection with the liquid fragrance, other types of thermoplastics may be used, and not only pellets but also powdery raw materials can be used.

In the above embodiment, the mixture of the pellets and the fragrance was stored in a container and allowed to stand at room temperature and room temperature. But,
It is possible to further promote the impregnation by leaving the device in an environment of about 40 to 50 degrees Celsius heated to room temperature or in a pressurized atmosphere.

In the above embodiment, a plastic bag such as nylon or polyethylene is used as the sealed container. However, the sealed container is not limited to these plastic bags, and a plastic or metal container of another shape may be used. However, it is desirable to use a plastic bag as the sealed container because the washing of the fragrance permeated by disposable can be omitted.

[0031]

As described above, according to the features of the present invention, it is possible to obtain a molded article made of a homogeneous thermoplastic while maintaining the emission of fragrance for a long period of time by including a fragrance into the interior of the molded article. It has become possible to provide a method for producing a plastic molded article that emits an aroma that can be used. Moreover, according to the present invention, the fragrance and the plastic pellets and the like may be mixed as needed, which is very suitable for small lot production.

Further, by using an ethylene-vinyl acetate copolymer resin as the plastic, the liquid fragrance can be impregnated without waste, and the fragrance in the center can be effectively diffused due to the air permeability of the plastic. It became possible to maintain the scent sufficiently long for the amount of the fragrance used.

Further, by leaving the mixture in a sealed container after stirring, it is possible to absorb the fragrance into plastic pellets and the like without waste. Further, the mixing in the hopper has made it possible to improve the production speed.

It should be noted that the reference numerals described in the claims are merely for convenience of comparison with the drawings, and the present invention is not limited to the configuration of the attached drawings by the description. .

[Brief description of the drawings]

FIG. 1 is a schematic side view of an injection molding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Hopper 3 Screw part 4 Screw drive part 5 Die

Claims (6)

[Claims] 1. A method for producing a plastic molded article which emits a fragrance, comprising mixing a pellet or powder (hereinafter referred to as “pellet or the like”) of a thermoplastic and a liquid fragrance into said pellet or the like. Impregnated with fragrance,
Thereafter, the mixture is molded by a molding machine. 2. The method according to claim 1, wherein the plastic is an ethylene-vinyl acetate copolymer resin (EVA). 3. The method according to claim 2, wherein the content ratio of vinyl acetate in the plastic is 2% to 40% by weight. 4. The pellet or the like and the liquid fragrance are stirred and mixed in a container, and the container is left in an airtight state to be impregnated with the fragrance into the pellet and the like. The method for producing a plastic molded article emitting fragrance according to any one of claims 1 to 3, wherein 5. The method according to claim 4, wherein the standing time is 1 hour or more and 72 hours or less. 6. The plastic molded article emitting fragrance according to claim 1, wherein the molding is performed after the pellets and the like and a liquid fragrance are mixed in a hopper (2) of the molding machine (1). Manufacturing method.