JPS6115827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention retains odorants such as fragrances inside plastic moldings, and prevents the volatilization of odorants little by little.
This relates to plastic moldings that are intended to last for a long period of time.

Conventionally, methods for imparting fragrance to plastics include methods in which solid powder fragrances, such as vanillin, synthetic musk, and coumarin, are directly kneaded into plastics, heated, and melted, plasticizers, or A method in which a filler or the like is used as a retention agent, kneaded into a plastic together with a fragrance, and then heated and melted; a fragrance crude oil is adsorbed into a porous fine powder such as silicic acid or silicic anhydride; There are methods such as preparing fine perfume particles and dispersing them in heat-molten plastic, and adding perfume to powdered plastic and sintering it, but the duration of volatilization of the odorant is from several weeks to 2 to 3 months. In many cases, it is almost impossible to control the odor. Generally, odorants have a threshold value of 5×10 ^-6 per 1 air for synthetic musk.
If the amount exceeding 5× ^-9 mg) is not always volatilized, the fragrance cannot be felt, but if too much is volatilized, it will be perceived as a bad odor, so the amount of odorants volatilized is It is necessary to keep it within a certain range. As in the past, when aromatic plastics are made from plastics with high permeability to odorants, such as low-density polyethylene or soft vinyl chloride resin, in single-layer plastic molded products, the volatilization rate of the odorants is fast; Therefore, in the early stage, the amount of odorants volatilized is too large, but on the other hand, the amount of odorants volatilized decreases in a short period of time, and its lifespan is short. In addition, when aromatic plastics are made from plastics with high barrier properties against odorants, such as polyacetal or polyamide resin, the volatilization rate of the odorants is slow, and therefore, although the odorants continue to volatilize for a long period of time, the amount of volatilization decreases. There is a problem that becomes too small.

The present invention was invented to solve these problems, and the first invention is a synthetic resin that is made by dispersing odorants such as fragrances in a synthetic resin that has high permeability. The second invention is an aromatic plastic molded product consisting of an inner core layer and a synthetic resin coating layer with low permeability to odorants. It is an aromatic plastic molded product consisting of a synthetic resin inner core layer with a high odour, and a synthetic resin coating layer with a low permeability to odorants.

In the first aspect of the present invention, in order to disperse the odorant in the resin, it is sufficient to knead the odorant and the resin, and in order to improve fragrance retention, adsorbent porous powder, such as white carbon, is used. By adsorbing fragrance crude oil into silicic acid, calcium carbonate, talc, clay, etc., and then kneading it with plastic, kneading micro-encapsulated odorants, or adding odorants to powdered resin. Alternatively, a surfactant may be added to make it easier for odorants to pass through.

In the second aspect of the invention, the odorant to be filled into the cavity inside the inner core layer is a natural or synthetic fragrance, or a fragrance crude oil prepared by adjusting the desired fragrance raw material according to the blended fragrance amount thereof.

In addition, resins used in the coating layer as barrier resins against odorants include nitrile resins, polyacetals, polyamide resins, saponified ethylene-vinyl acetate copolymers, polybutylene terephthalate, polyethylene terephthalate, and hard vinyl chloride. A resin or the like may be considered, but it is necessary to select it depending on the type of odorant contained in the inner core material.

To make the plastic molding of the present invention,
It can also be obtained by multi-stage injection molding in which the molded product is placed in successively larger molds and injected into multiple layers, but it is also possible by the Sand-German injection molding method. In other words, the resin for the inner core layer and the barrier resin are heated and melted in separate injection cylinders, and then passed through the same mold through the same gate. Injection filled with barrier plastic,
Before the center of the barrier plastic in the mold cavity has cooled and solidified, the transparent plastic for the inner core layer is injected and filled into the resin for the outer layer in the mold cavity. After that, you may further inject and fill the coating layer resin, or create a cavity inside.
Part of the mold may be moved.

As described above, the molded article according to the present invention can contain fragrance crude oil that exceeds the usage or molding limit in a single layer, such as 30 parts of rose fragrance oil per 100 parts of low-density polyethylene. The amount of fragrance diffused can be determined by cutting off part of the coating layer or the convex part according to your preference, so it is not only possible to maintain the desired amount of volatilization for a very long period of time. Barrier resins with excellent fragrance retention are generally rigid, so they are less likely to be damaged and less likely to generate static electricity, so they are less likely to get dirty. Furthermore, the fragrance-bearing properties can be immediately restored by washing with water or rubbing.

Since the molded product of the present invention is used by cutting off a portion of its coating layer, it is desirable that the molded product has a shape that is easy to cut. The examples shown in FIGS. 1a and 2a are examples of this. In other words, it is possible to make cuts in the coating layer 2 to make it easier to cut out, or to make a portion of the coating layer 2 convex to make it easier to cut out the convex part. can. FIG. 1b and FIG. 2b each show a state in which a portion of the covering layer 2 is cut away to expose the inner core layer 1.

In addition, the product of the present invention can hold odor substances in plastic at a high concentration, so it can be used for very small molded products.
It can also be applied to complex molded products and thin molded products, such as scented earrings, rings, and combs, as well as toilet products containing deodorant.
The practical effects of the present invention are significant.

Note that the object of the present invention can also be achieved even if an intermediate layer made of adhesive resin is provided between the coating layer and the inner core layer of the present invention.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention, and Fig. 1a and Fig. 2b are cross-sectional views of the molded product of the invention, and Fig. 1b and Fig. 2b are cross-sectional views of the molded product of the present invention when a part of the coating layer is cut away. FIG. 1...Inner core layer, 2...Coating layer.

Claims (1)

[Claims] 1. An aromatic plastic molded product consisting of an inner core layer made by dispersing odorants in a synthetic resin that has high permeability to odorants such as fragrances, and a synthetic resin coating layer that has cuts or protrusions and has low permeability to odorants. .