JP3252554B2 - Processing method of polyolefin stretch blow molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a polyolefin stretch blow-molded product comprising a polyolefin containing 5 to 60 mol% of a cyclic olefin component such that the crystallinity is 20% or less.

[0002]

2. Description of the Related Art Conventionally, a polyester resin such as polyethylene terephthalate has been used as a material of a container formed by a stretch blow molding method, and the container has excellent physical properties (light weight, transparency, moderate rigidity, etc.). It is widely used as containers for beverages including carbonated beverages, seasonings, cosmetics, liquid detergents, and the like. Also, stretch blow containers obtained from polyolefin resins such as polypropylene,
It has excellent water vapor barrier properties and transparency, and is used as a container for contents (salts, seasonings, tablets, etc.) that dislike moisture.

However, stretch blow molding of a polyolefin resin is difficult to mold due to its high crystallinity (30 to 60%) and the like, and is practically used only with some polypropylene copolymer grades. However, since the polypropylene copolymer has a large amount of ethylene components, it has disadvantages such as low rigidity. Also, when the container is no longer needed, it is bulky or the polyolefin-based resin has a high calorie of burning, and is in trouble with the treatment method.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for treating a polyolefin stretch blow-molded article which is rigid and easy to stretch-mold.

[0005]

Means for Solving the Problems] ie, the present invention has a melting point higher than the glass transition point polyolefin Tona Lupo Li olefin manufactured stretch blow molded article having a 5 to 60 mol% cyclic <br/> shape olefin components This is a method for treating a stretch blow-molded product made of polyolefin, which is heated to a temperature less than that to return to a preform shape before stretch blow.

(Detailed Description) The details of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a preform used in the present invention. The preform is threaded (1)
And a flange portion (2) that plays a role of supporting the preform at the time of stretching and a cylindrical portion (3) having a bottom portion of the preform body. Examples of the method for producing the preform include methods such as injection molding, extrusion molding, compression molding, and machining, and a combination method thereof.

The material to be used is a polyolefin-based resin consisting only of hydrogen and carbon, and if there are factors such as a cyclic structure which inhibits the crystal structure and a high structure in the main chain skeleton or side chain. Although good, a polyolefin-based resin having a cyclic olefin component in the main chain skeleton “cyclic polyolefin copolymer” is preferably used. By having a cyclic olefin component in the main chain skeleton of the polyolefin resin, inhibits the crystal structure of the polyolefin resin,
Crystallinity can be controlled to 20% or less.

[0008] By increasing the content of the cyclic olefin component, an amorphous polyolefin can also be obtained. Also,
By increasing the content of the cyclic olefin component,
The heat deformation temperature can be increased, and 4.6 kg / cm ²
A cyclic polyolefin having a heat resistance of 180 ° C. under a load of is also obtained.

As the cyclic olefin component, for example,
Black (2.2.1) hept-2-ene or derivatives thereof
Body, tetracyclo (4.4.0.1^2,5. 1^7,10) -3
-Dodecene or a derivative thereof, hexacyclo (6.6.
1.1^3,6. 1^10,13. 0^2,7. 0^9,14) -4-hepta
Decene or a derivative thereof, octacyclo (8.8.0.
1^2,9. 1^4,7. 1^11,10. 1^13,16. 0^3,8. 0
^12,17) -5-Docosene or a derivative thereof, pentacyclo
B (6.6.1.1^3,6. 0^2,7. 0^9,14) -4 Hex
Decene or a derivative thereof, pentacyclo (6.5.1.
1^3,6. 0^2,7. 0^{9, 13}) -4-Pentadecene or its equivalent
Heptacyclo (8.7.0.1)^2,9.
1^4,7. 1^11,17. 0^3,8. 0^12,16) -5-eicose
Or a derivative thereof, heptacyclo (8.8.0.1
^2,9. 1^4,7. 1^11,16. 0^3,8. 0^12,17) -5-f
Eicosene or a derivative thereof, tricyclo (4.4.
0.1^2,5) -3-undecene or a derivative thereof, tri
Cyclo (4.3.0.1^2,5) -3-Decene or its
A derivative, pentacyclo (6.5.1.1)^3,6. 0^2,7.
0^9,13) -4,10-Pentadecadiene or derivatives thereof
Body, pentacyclo (4.7.0.1 ^2,5. 0^8,13. 1
^9,12) -3-Pentadecene or a derivative thereof heptacycline
B (7.8.0.1^3,6. 0^2,7. 1^10,17.
0^11,16. 1^12,15) -4-Eicosene or its induction
Body, nonacyclo (9.10.1.1)^4,7. 0^3,8. 0
^2,10. 0^{12 ,twenty one}. 1^13,20. 0^14,19. 1^15,19) -5
-Pentasecon or its derivatives, etc.
You.

Examples of the polyolefin component containing a cyclic olefin component include ethylene and propylene, 1-butene, 1-pentene, 4-methyl-pentene, 3-methyl-pentene, 1-hexene, 1-heptene, 1 -Octene, 1-nonene, 1-decene and the like.
Copolymers composed of more than one component may be used.

In the cyclic polyolefin copolymer containing a cyclic olefin component, the structural unit derived from the olefin component such as the ethylene component is in the range of 40 to 95 mol%, preferably 50 to 80 mol%, derived from the cyclic polyolefin component. The structural unit is effective from the addition of 1 mol%, but from the viewpoint of heat resistance, usually 5 to 60 mol%, preferably 20 to 20 mol%.
The range of 50 mol% is appropriate, and structural units derived from an olefin component such as an ethylene component and structural units derived from a cyclic olefin component are randomly arranged to form a cyclic polyolefin copolymer.

Since it is a polyolefin resin, it has excellent water vapor barrier properties and resistance to chemicals such as acids and alkalis. As a method for stretch-molding the preform, heating is performed by heating with an infrared heater or contact heating, and the preform body cylindrical portion (3) is heated to 80% depending on the content of the annular structure.
After the temperature is raised to 220 ° C to 220 ° C, the preform is gradually cooled to lower the temperature to 60 to 190 ° C to make the temperature distribution of the cylindrical section (3) having the bottom of the preform uniform. Thereafter, by performing stretch blow molding using both the stretching rod (4) and the compressed air, a final molded product can be obtained.

The pressure and speed of the stretching rod depend on the shape of the preform used and the shape of the final molded product, but are usually 3 to 20 kgf / cm ² and 2 to 5 kgf / cm 2.
The stretching rod can be moved at a speed of 0 cm / s. The compressed air used can set the primary blow pressure and the secondary blow pressure, and the primary blow pressure is 1 to 10 kg.
f / cm ² Secondary blow pressure is 10 to 40 kgf / cm ²
A pressure setting of about The primary blow pressure and the secondary blow pressure do not always need to be separated, and stretch blow molding can be performed by a single pressure, and the forming method is not limited.

FIG. 2 shows a drawing of a stretch-formed cyclic polyolefin.
A conceptual diagram is shown. FIG. 3 shows another pre-format used in the present invention.
A cross-sectional view of the arm (forming precursor) is shown. Figure 3
The arm has a disk-like shape, and a thick portion is provided at the central thick portion (6).
And a rib (5) on the periphery of the disk.
You. The central thick part (6) of the preform is selectively infrared
Heat with a wire heater, and at 80 ° C by the same method as above.
~ 220 ° C, then slowly cooled to 60-190 ° C
Temperature, and set the temperature of the central thick part (6) to be uniform
I will do it. Thereafter, the stretching rod (4) and the compressed air
By performing stretch blow molding with the use of air,
The final molded product shown can be obtained. Also stretch blow
The preform temperature during molding is controlled uniformly, and several kgf /
cm ^TwoStretch blow molding at a pressure of
Even in the hot parison method where molding of
Molding of the olefin copolymer is possible.

[0015] Further, by having a cyclic olefin component in the main chain skeleton of the polyolefin-based resin constituting the obtained final molded article, the polyolefin resin has excellent shrink properties, and the final molded article is obtained. When the final molded article becomes unnecessary after use, the final molded article is easily returned to the preform shape and is not bulky by heating it at a temperature from the glass transition point to the melting point but below the melting point.

Specifically, the heating temperature varies depending on the content of the cyclic olefin component,
If it is 30 mol%, the molded article can be returned to the preform by heating at 70 ° C to 100 ° C, and can be easily returned to the preform simply by immersing it in boiling water. If the cyclic olefin component is 30 to 60 mol%, the container is not deformed when it is immersed in boiling water, and is returned to the preform by storing it in an oven at 100 ° C to 200 ° C.

As described above, by changing the content of the cyclic olefin, the heat resistance of the molded article and the ease of returning to the preform can be easily changed. The returned preform is washed, stretch blow molded again, and can be used as a stretch blow molded product.
Compared with the bottle shape, it is less complicated, so that it is easy to wash, and it is more hygienic than reusing the bottle as it is.

Further, by utilizing the return to the preform shape, a complicated picture or sculpture can be decorated on a molded article. For example, blow molding,
Processed by injection molding or the like, the container is used as a preform, stretch blow-molded, printed, engraved, etc. on the stretch blow-molded product, and then reheated at a glass transition point or higher and a melting point or lower to obtain the preform shape. In other words, by returning to the shape of the container to be used, a container with a complicated pattern and engraving can be obtained.

[0019]

According to the present invention, since the stretch blow-molded article is a polyolefin stretch blow-molded article composed of a polyolefin having a cyclic olefin component of 5 to 60 mol%, the inherent properties of the polyolefin are water vapor barrier properties and transparency. A stretch blow-molded product made of polyolefin having heat resistance and rigidity in addition to heat resistance and chemical resistance can be obtained. In addition, since a polyolefin having a cyclic olefin component of 5 to 60 mol% is used as a material for a preform for stretch blow molding, the degree of crystallinity becomes 20% or less, and stretch blow molding becomes possible. A polyolefin stretch blow-molded product comprising a polyolefin having a cyclic olefin component of 5 to 60 mol% can be returned to a preform shape before stretch blow by heating at a temperature not lower than the glass transition point and lower than the melting point. .

[0020]

【Example】

<Example 1> A cyclic polyolefin copolymer (cyclic olefin component; 25%, ethylene component; 75 mol%) was injection-molded, a flange portion having a diameter of 30 mm and a diameter of 27.4 mm.
A preform (bottomed parison) having a body portion of 120 mm in length and 3.4 mm in thickness was obtained. The preform was reheated to 110 ° C. and gradually cooled to a uniform preform temperature of 90 ° C.
And stretching rod pressure; 7 kgf / cm ² , primary blow; 1.0 kgf / cm ² , 1 s, secondary blow; 20 k
Stretch blow molding at gf / cm ² , 3 s, longitudinal stretch ratio 2.0 times, transverse stretch ratio 2.4 times, bottle height 235 m
Thus, a 500 ml stretch blow container having a diameter of 65 mm and a diameter of 65 mm was obtained. It is a very rigid and rigid container with a transparent appearance and a thickness of 0.4 mm. Water vapor barrier property of the container,
The haze and the like were measured. Using the preform and the same stretch blow molding method, the longitudinal stretch ratio was 1.4.
A 300-ml stretch blow container having a draw ratio of 2.2 times, a draw ratio of 2.2 times, a bottle height of 165 mm, and a diameter of 60 mm was also obtained.

<Example 2> A cyclic polyolefin copolymer having a cyclic olefin component of 40 mol% and an ethylene component of 60 mol% in Example 1 was used, and injection molding was performed in the same manner as in Example 1 to obtain a similar preform. Then, the maximum heating temperature was set to 170 ° C. and the stretching temperature was set to 155 ° C., and the composition was stretched and blown in the same manner as in Example 1 to obtain a 500 ml container similar to that in Example 1. The resulting container was transparent, excellent in water vapor barrier properties, excellent in heat resistance, and did not undergo any significant change such as shrinkage even when stored in an oven at 120 ° C. for 2 hours or filled with boiling water.

Example 3 A cyclic polyolefin copolymer containing 5 mol% of a cyclic olefin component and 95 mol% of an ethylene component in Example 1 was injection-molded in the same manner as in Example 1, and the same preform was used. Was stretched and blown in the same manner as in Example 1 to obtain a 500 ml container similar to that in Example 1. The obtained container was transparent and had excellent water vapor barrier properties.

Example 4 Injection was carried out in the same manner as in Example 1 except that the cyclic polyolefin copolymer of Example 1 was 50 mol%, the ethylene component was 25 mol%, and the propylene component was 25 mol%. The preform was molded to obtain the same preform. The preheating was performed at a maximum heating temperature of 180 ° C. and a stretching temperature of 160 ° C., followed by stretching blow in the same manner as in Example 1. The obtained container was transparent and had excellent water vapor barrier properties.

<Comparative Example> In place of the cyclic polyolefin copolymer of Example 1, polyethylene having 0% of a cyclic structural component was used, and injection molding was performed in the same manner as in Example 1 to obtain a similar preform. Stretch-blowed in the same way as
No container was obtained. The above Examples to Comparative Examples are shown in (Table 1).

[0025]

[Table 1]

<Example 5> The container of Example 1 was returned to the preform shape and was not bulky simply by leaving it in hot water at 90 ° C for 5 minutes or in an oven at 80 ° C for 10 minutes. The preform left in an oven at 80 ° C. for 10 minutes was reheated again by the above method and stretch blow-molded under the same conditions to obtain a stretch blow container having a capacity of 500 ml. The appearance and rigidity were comparable to those of the first container.

<Embodiment 6> Even if stored in a 120 ° C. oven for 2 hours or filled with boiling water, a large change such as shrinkage does not occur and the container of Example 2 which is excellent in heat resistance is placed in a 150 ° C. oven. Even after standing for 10 minutes, it returned to the preform shape which was not easily bulky.

[0028]

As described in detail above, the invention using a cyclic polyolefin copolymer having a cyclic olefin component in a polyolefin as a material of a preform for stretch blow molding provides transparency, water vapor barrier properties, heat resistance, rigidity, etc. Excellent stretch blow molded products can be easily obtained. In addition, the use of the cyclic polyolefin copolymer has a specific gravity 2.5% smaller than that of a polyester molded product such as polyethylene terephthalate, so that the weight of the molded product can be reduced despite a tough molded product. In addition, organic solvents, acids,
It has excellent chemical resistance to alkalis, etc., so there is no restriction on the contents, and the range of use as a molded product is wide. Ideal for containers.

Further, when the stretch blow-molded article is no longer needed, it returns to a preform shape which is not bulky only by heating. In addition, a complicated pattern or engraving can be applied to a molded article by utilizing the property of shrinking to the original preform by heating the stretch blow molded article.

[0030]

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a preform used in the present invention.

FIG. 2 is a conceptual explanatory view of stretch molding of a cyclic polyolefin copolymer.

FIG. 3 is an explanatory sectional view of another preform (forming precursor) used in the present invention.

FIG. 4 is a view showing a final molded product obtained by stretch blow molding the preform of FIG. 3;

[Description of Signs] 1 ... Screw part 2 ... Flange part 3 ... Cylindrical part with bottom 4
... Stretched rod 5 ... Rib 6 ... Central thick part 7 ... Final molded product

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kiyoshi Wada 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. Examiner Yasuhide Nomura (56) References JP 3-726 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 49/00-49/80 B65D 1/00-1/48 B09B 3/00

Claims (1)

(57) [Claims] (1) a cyclic olefin component having 5 to 60 mol%;
Stretch blow made of polyolefin
Heat the molded product at a temperature between the glass transition point and the melting point
To return to the preform shape before stretch blow
Stretch blow molded product made of polyolefin
Processing method.