JP6534313B2 - Manufacturing method of resin container - Google Patents

Description

  The present invention relates to a method for producing a resin container having a pearly luster (pearl luster).

  BACKGROUND ART Conventionally, a resin-made container having a pearly luster has been used, for example, as a container for containing a content liquid such as a lotion and a container for the refill thereof. Such a resin container is generally produced by giving a pearly luster to the surface of the container after molding by a post-process such as painting or vapor deposition, but such a manufacturing method is expensive Since it is necessary to use a pearl pigment, there is a problem that the production cost is increased.

  As what solves such a problem, for example, in patent document 1, while mixing the pellet of polyethylene naphthalate resin and the pellet of polyethylene terephthalate resin in a predetermined ratio, the mixed pellet made into the predetermined dry state is It is a technology to manufacture a resin container having a pearly gloss by preparing and heating, melting and kneading the mixed pellet at a predetermined temperature and extrusion blow molding (direct blow molding) at a predetermined blow ratio. Have been described. According to such a production method, it is possible to produce a resin container having a pearly luster at low cost without using an expensive pearl pigment.

JP, 2010-89319, A

  However, while the resin container manufactured by the above-mentioned conventional manufacturing method has a pearly luster, the water barrier property is not sufficient, and when it is stored for a long time after filling with the content liquid, the container is There has been a problem that decompression deformation such as a dent or the like may cause composition change (deterioration) of contents.

  This invention is made in view of such a subject, The objective is the manufacturing method of the resin-made container which can manufacture the resin-made container which has a pearl-like luster and has high water-barrier property at low cost. To provide.

The method for producing a resin container according to the present invention comprises the drying step of drying a polyester resin, and the cyclic polyolefin resin having a glass transition temperature of less than 100 ° C. and a cyclic olefin content of 50 to 100 wt%. A material mixing process for obtaining a mixed resin material by mixing in a ratio of 3 to 20 wt% with the polyester resin after drying at the following temperature, and a mixed resin material obtained in the material mixing process is injection molded to obtain a preform And a blow molding step of blow molding the preform heated to a temperature capable of drawing into a container of a predetermined shape having a pearly luster .

  In the method for producing a resin container according to the present invention, in the above configuration, the polyester-based resin is preferably polyethylene terephthalate.

  In the method for producing a resin container according to the present invention, in the above configuration, the cyclic polyolefin resin is preferably a cycloolefin copolymer.

  In the method for producing a resin container according to the present invention, in the above configuration, the cyclic polyolefin resin is preferably a cycloolefin polymer.

  In the method for producing a resin container according to the present invention, in the above configuration, the polyester resin is heated and dried and then cooled to a temperature equal to or less than the glass transition temperature of the cyclic polyolefin resin in the drying step. can do.

  In the method for producing a resin container according to the present invention, in the above configuration, the polyester-based resin can be dried at a temperature lower than the glass transition temperature of the cyclic polyolefin-based resin in the drying step.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the resin-made containers which can manufacture cheaply the resin-made container which has pearl glossiness and has high water-barrier property can be provided.

It is a front view which shows an example of the resin-made containers manufactured by the manufacturing method of the resin-made containers which are one embodiment of this invention. It is a figure which shows the procedure of the manufacturing method of the resin-made containers which are one embodiment of this invention. It is a figure which shows the measurement result of the moisture permeability in, when the resin-made containers of Example 1, 2 and the resin-made containers of a comparative example are stored on storage conditions of 22 degreeC-55% RH of air temperature. It is a figure which shows the measurement result of the moisture permeability in, when the resin-made containers of Example 1, 2 and the resin-made containers of a comparative example are stored on storage conditions of air temperature 40 degreeC-55% RH. It is a figure which shows the measurement result of the moisture permeability in, when the resin-made containers of Example 1, 2 and the resin-made containers of a comparative example are stored on storage conditions of air temperature 50 degreeC-55% RH.

  Hereinafter, the method for producing a resin container according to an embodiment of the present invention will be more specifically described with reference to the drawings.

The method for producing a resin container according to the present invention comprises the drying step of drying a polyester resin, and the cyclic polyolefin resin having a glass transition temperature of less than 100 ° C. and a cyclic olefin content of 50 to 100 wt%. The mixed resin material obtained in the material mixing process to obtain a mixed resin material by mixing in a proportion of 3 to 20 wt% with the polyester resin after drying at the following temperature, and injection molding of the mixed resin material obtained in the material mixing process to form a preform And a blow molding step of blow molding the preform heated to a temperature capable of drawing into a container of a predetermined shape having a pearly luster .

  According to such a manufacturing method, it is possible to inexpensively manufacture a resin container having a pearly luster (pearly luster) and a high moisture barrier property. An example of the resin-made container manufactured by FIG. 1 by the manufacturing method of the resin-made containers of this invention is shown.

  The resin container 1 shown in FIG. 1 can be used, for example, as a container for food, medicine and cosmetics and its refill container, and is a cylinder connected to the cylindrical opening 2 and the opening 2 via the shoulder 3. And a bottom 5 for closing the lower end of the trunk 4. The body 4 is provided with two concave ribs 6 for reinforcing the body 4, and a neck ring 7 is provided below the mouth 2. In addition, a thread 8 for fixing a cap (not shown) to the opening 2 is provided on the outer peripheral surface of the opening 2. In addition, it changes to the screw thread 8 and can provide an annular protrusion in the opening 2, and it can also be set as the structure which pierces and fixes the cap provided with the undercut shape to the opening 2. FIG.

  The resin container 1 blows a preform formed of a mixed resin material in which a cyclic polyolefin resin having a glass transition temperature of less than 100 ° C. is added at a predetermined weight ratio to a polyester resin as a base material. By molding, it is formed into a container having a pearly luster (pearly luster). The resin container 1 has high water barrier properties, for example, 1% or less of water permeability after one month when the storage conditions are 40 ° C. and 55% relative humidity.

  As shown in FIG. 2, the method for manufacturing a resin container according to an embodiment of the present invention is performed in the following procedure.

  First, a polyester-based resin and a cyclic polyolefin-based resin having a glass transition temperature of less than 100 ° C. are prepared as raw materials of a resin-made container.

  Although various types of polyester resins can be used as the base resin, it is particularly preferable to use polyethylene terephthalate (PET).

  On the other hand, a cycloolefin copolymer (COC) having a glass transition temperature of less than 100 ° C. can be used as the cyclic polyolefin resin to be an additive. As the cycloolefin copolymer, for example, "TOPAS (registered trademark) 8007" sold by Polyplastics Co., Ltd. can be used. The glass transition temperature of this cycloolefin copolymer is 78 ° C. and the cyclic olefin (norbornene) content is about 65 wt%.

  The cyclic polyolefin resin is not limited to the above-described cycloolefin copolymer, but may be other cyclic polyolefin resin such as cycloolefin polymer (COP) as long as the glass transition temperature is less than 100 ° C. it can.

  Moreover, as cyclic polyolefin resin, it is preferable to use that whose cyclic olefin content rate is 50-100 wt%. By using such a cyclic polyolefin resin, a resin container having high moisture barrier properties can be manufactured.

  Each of these polyester resins and cyclic polyolefin resins can be pelletized.

  When the raw material is prepared, first, in the drying step, the polyester-based resin is dried to a predetermined dry state that enables injection molding.

  This drying step can be performed, for example, by heating and drying a polyester resin to a predetermined temperature and drying. When the drying step is carried out by heating and drying, the drying step is heated to a temperature above the glass transition temperature of the cyclic polyolefin-based resin to be mixed with the polyester-based resin, to a predetermined dry state After drying, the polyester resin after drying can be cooled to a temperature equal to or lower than the glass transition temperature of the cyclic polyolefin resin.

  The drying step is not limited to heating and drying as described above, but may also be performed by low temperature drying in which a polyester resin is dried at a temperature below the glass transition temperature of the cyclic polyolefin resin to be mixed therewith. it can. In this case, vacuum drying may be employed as the low temperature drying.

  In the drying step using any drying method, the polyester resin after drying is at a temperature equal to or less than the glass transition temperature of the cyclic polyolefin resin to be mixed therewith.

  Next, in the material mixing step, the cyclic polyolefin resin having a glass transition temperature of less than 100 ° C. is dried to a predetermined dry state in the drying step and mixed with the polyester resin having a temperature not higher than the glass transition temperature. To produce a mixed resin material. The polyester-based resin and the cyclic polyolefin-based resin can be mixed, for example, by uniformly mixing (dispersing) the polyester-based resin and the cyclic polyolefin-based resin in the pellet state, and then melting and kneading them. .

  Here, when the heat-dried polyester-based resin has a temperature equal to or higher than the glass transition temperature of the cyclic polyolefin-based resin, the cyclic polyolefin-based resin mixed with the polyester-based resin is glass transitioned by the heat of the polyester-based resin The cyclic polyolefin resin melts to one another, or the cyclic polyolefin resin melts to the polyester resin to form a mass, and the mass blocks the supply path to the melt-kneaded portion. It becomes difficult to mix the polyester resin and the cyclic polyolefin resin uniformly. On the other hand, in the present invention, the polyester resin after drying is set to a temperature equal to or lower than the glass transition temperature of the cyclic polyolefin resin, so the cyclic polyolefin resin mixed with the polyester resin has a glass transition temperature. The polyester resin and cyclic polyolefin resin are uniformly mixed while being uniformly mixed, and reliably supplied to the melt-kneaded part through the supply passage, and the polyester resin and the cyclic polyolefin resin are homogeneously mixed. can do. That is, even if a cyclic polyolefin resin having a relatively low glass transition temperature, ie, a glass transition temperature of less than 100 ° C., is used, the temperature of the polyester resin after drying is made lower than the glass transition temperature. The base resin and the cyclic polyolefin resin can be homogeneously mixed. Therefore, the manufacturing method of this resin-made container can be made easy, without impairing the productivity of resin-made containers.

  In this material mixing step, it is preferable to mix the cyclic polyolefin resin with the polyester resin in a proportion of 3 to 20 wt%, and more preferably in the proportion of 5 to 10 wt%. By setting the ratio as such, it is possible to manufacture a resin container having an appropriate pearly luster and moisture barrier property.

  Next, in the preform forming step, the mixed resin material obtained in the material mixing step is injection-molded to form a preform having a predetermined shape. This preform molding process can be performed using an injection molding machine. In this case, the mixed resin material mixed in the material mixing step can be automatically supplied to the injection molding machine by a conveyor or the like using a screw.

  The preform to be formed in this preform forming step is a resin container after production, such as a bottomed cylindrical (substantially test tubular) one having a mouth, a body and a bottom and a rectangular cylinder with a bottom. It can be formed into various shapes according to the shape of.

  Next, in the blow molding step, the preform molded in the preform molding step is heated to a temperature at which it can be stretched, and blow molded into a container of a predetermined shape in that state. As a result, a resin container having a pearly luster (pearly luster) and a high water barrier property is completed.

  The blow molding can be performed by air blow molding using pressurized air as a pressurized medium (pressurized fluid), but can also be performed by liquid blow molding using a pressurized liquid as a pressurized medium.

  In the blow molding step, the preform is heated to a stretchable temperature, which is preferably set to 100 ° C to 120 ° C. If the temperature of the preform is less than 100 ° C., the drawability of the preform is insufficient, and the formability of the container is reduced. On the other hand, if the temperature of the preform is higher than 120 ° C., the polyethylene terephthalate may become cloudy, and the pearly gloss may be impaired.

  Thus, according to the resin container manufacturing method of the present invention, since a resin container having a pearly luster can be manufactured without using an expensive pearl pigment, the manufacturing cost can be reduced. it can. Further, according to the method for producing a resin container of the present invention, the resin container is produced from a mixed resin material in which a cyclic polyolefin resin is mixed with a polyester resin, so that the moisture barrier of the produced resin container Can be enhanced.

  As a resin container manufactured by the method for manufacturing a resin container according to the present invention, a polyethylene terephthalate (polyester resin) is used as a substrate, and a cyclopentadiene resin having a glass transition temperature of 78 ° C. and a cyclic olefin content of about 65 wt% The resin container of Example 1 using a mixed resin material in which 10 wt% of an olefin copolymer (cyclic polyolefin resin) is mixed, and polyethylene terephthalate as a base material, and having a glass transition temperature of 78 ° C. and a cyclic olefin content of While manufacturing the resin container of Example 2 using the mixed resin material which mixed 5 wt% of cycloolefin copolymer of about 65 wt%, the resin container which manufactured only polyethylene terephthalate as a raw material as a comparative example is manufactured, and these Resin volume of each of Examples 1 and 2 and Comparative Example An evaluation of the moisture barrier properties were performed on.

  Each of the resin containers of Examples 1 and 2 and Comparative Example had the shape shown in FIG. 1 and had a total height of 135.8 mm, a full dose volume at 20 ° C. of 138.2 ml, and an inner diameter of the mouth portion The maximum diameter of 14.9 mm and the body is 42.0 mm.

  For evaluation of the moisture barrier property, storage conditions are: temperature (storage temperature) 22 ° C., relative humidity 55%, temperature (storage temperature) 40 ° C., relative humidity 55% and temperature (storage temperature) 50 ° C. 55 The temporal change of water permeability was measured under each condition. The water permeability is a measure of the initial weight and the weight after a certain period of time for a resin container filled with water, and the amount of change is represented by the rate of change with respect to the initial weight. The change in moisture permeability is shown in Figure 3 when the storage condition is 22 ° C and 55% RH, and the measurement result is shown in Figure 4 when the storage condition is 40 ° C and 55% relative humidity. The measurement results are shown in FIG. 5 when the storage conditions are an air temperature of 50.degree. C. and a relative humidity of 55%.

  From the experimental results shown in FIGS. 3 to 5, the resin of the present invention can be used under the storage conditions of temperature 22 ° C., relative humidity 55%, temperature 40 ° C. relative humidity 55% and temperature 50 ° C. relative humidity 55%. It was found that the resin containers of Examples 1 and 2 manufactured by the method for manufacturing a container had a moisture barrier property higher than that of the resin container of the comparative example. For example, the moisture permeability (reduction rate) after one month has elapsed under the storage conditions of an ambient temperature of 40 ° C. and a relative humidity of 55% is 0.77% for the resin container of Example 1 and the resin container of Example 2 It became clear that each had 0.91% or less and 1% or less, and had sufficient moisture barrier properties. On the other hand, in the case of the resin container of the comparative example, the moisture permeability after one month is 1.32% when the storage condition is 40 ° C. and 55% relative humidity, and the moisture barrier property is low. I understand.

  In addition, it was confirmed that the resin containers of Examples 1 and 2 were all formed in a container having a pearly luster. On the other hand, the resin container of the comparative example had no pearly luster.

  The present invention is not limited to the configuration described in the above embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.

  For example, in the above embodiment, although the resin container manufactured according to the method for manufacturing a resin container according to the present invention is illustrated in FIG. 1, the resin container manufactured according to the method for manufacturing a resin container is exemplified. The container can be of various shapes, volumes or sizes.

  Further, the pearly luster of the resinous container produced by the method for producing a resinous container according to the present invention is not limited to the white color, and is colored by, for example, adding a pigment or the like to the mixed resin material in the material mixing step. It can also have a pearly luster.

  Furthermore, the permeability of the resin container 1 manufactured by the method of manufacturing a resin container of the present invention can be appropriately set according to the mixing ratio of materials, etc., and has transparency (for example, transparent or translucent) And opaque, etc. can be set according to the purpose.

1 resin container 2 mouth 3 shoulder 4 barrel 5 bottom 6 concave rib 7 neck ring 8 thread

Claims (6)

A method of manufacturing a resin container, wherein
A drying step of drying the polyester resin,
A cyclic polyolefin resin having a glass transition temperature of less than 100 ° C. and a cyclic olefin content of 50 to 100 wt% is mixed with the polyester resin in a proportion of 3 to 20 wt% after drying at a temperature not higher than the glass transition temperature. Material mixing step to obtain a mixed resin material;
A preform molding step of injection molding the mixed resin material obtained in the material mixing step to form a preform;
A blow molding step of blow molding the preform, which has been heated to a stretchable temperature, into a container of a predetermined shape having a pearly gloss, and manufacturing the resin container.   The manufacturing method of the resin-made containers of Claim 1 whose said polyester-type resin is a polyethylene terephthalate.   The manufacturing method of the resin-made containers of Claim 1 or 2 whose said cyclic polyolefin resin is a cycloolefin copolymer.   The manufacturing method of the resin-made containers of Claim 1 or 2 whose said cyclic | annular polyolefin-type resin is a cycloolefin polymer.   The resin container according to any one of claims 1 to 4, wherein, in the drying step, the polyester resin is cooled to a temperature not higher than the glass transition temperature of the cyclic polyolefin resin after being heated and dried. Manufacturing method.   The method for producing a resin container according to any one of claims 1 to 4, wherein in the drying step, the polyester-based resin is dried at a temperature lower than the glass transition temperature of the cyclic polyolefin-based resin.

Images