JP4061619B2 - Blow molding container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blow molded container, and more particularly to a container having a small blow ratio formed by a direct blow molding method.
[0002]
[Prior art]
As shown in FIG. 20, in the direct blow molding method, a parison P that is a cylindrical molten resin is extruded by an extruder 121, and this parison P is subjected to a mold clamping process of a split mold 101 divided into two for blow molding. In the lower part of the mold, the lower part of the molten resin is cut with a cutting blade disposed in the bottom pinch-off part 105 of the cavity 102 of the split mold 101 and thermally welded and sealed, and the upper part is a cylindrical molten resin with a parison cutter 122. The parison P having a bottomed cylindrical body is formed by cutting the upper portion of the mold, and then blow air is blown into the parison P from the top of the split mold 101 by the inserted air nozzle to form a molded product.
[0003]
FIG. 6 shows an example of a conventional blow-molded container, and FIGS. 7 and 8 show an example of a conventional split mold. The split mold 101 is entirely composed of one plane (the main body split surface 111). ), And is formed by a biting blade 106 on the bottom surface 104 of the bottom 103 of the mold cavity 102 in a flat cross section when the mold 101 is closed (see FIG. 8C). The pinch-off line 114 is positioned on a main body dividing line 113 formed by 111 on the main body dividing surface.
[0004]
In addition, the width of the pinch-off portion 105, that is, the length in the left-right direction of the biting blade 106 is usually about 1.6 Dp, which is a width obtained by flatly crushing a cylindrical parison with an outer diameter Dp into two. As a result, a pinch-off line 14 having a length of approximately 1.6 Dp is formed on the same line as the main body dividing line 13 on the bottom of the bottom of the container which is a molded product. (See Figure 6)
[0005]
Conventionally, with respect to the structure near the bottom pinch-off portion of the blow molded container, various improvements have been implemented from the viewpoint of improving the strength and appearance of the bottom seal portion of the container, which is a molded product. There is a description of a method for improving the strength of the bottom seal portion of the laminated container by forming uneven pressing recesses on both sides of the pinch-off portion, and Patent Document 2 discloses a pinch-off portion below the pinch-off portion of the molding die. There is a description of a method for controlling the thickness of the bottom seal part by providing a compression plate for sandwiching a resin protruding from the part (hereinafter referred to as a burr).
[0006]
[Patent Document 1]
JP-A-7-88943
[Patent Document 2]
JP-A-9-262902
[0007]
[Problems to be solved by the invention]
As described above, a pinch-off line of approximately 1.6 Dp is usually formed on the bottom bottom surface of a container that is a direct blow-molded product. However, in a container having a sufficiently large blow ratio, the formation range of the pinch-off line is at the periphery of the bottom surface. Since it does not reach, it is used for many purposes without problems in appearance. However, in blow molding of a container with a low blow ratio, the pinch-off part is close to or equal in width to the bottom diameter at the bottom of the mold cavity, so that the parison is crushed flatly in the pinch-off process. The resin is deformed in the horizontal direction along the main body mold dividing surface located on the left and right from the left and right ends of the part, or the resin forming the parison flows. In the vicinity of the line, the protruding resin remains, so-called burrs are formed, and burrs are left in the product container.
[0008]
For example, in a container having a blow ratio of about 2, the width of the pinch-off portion can be made smaller than the diameter of the bottom bottom surface of the container, but the resin forming the parison by being pinched off and crushed by the pinch-off portion Flowing laterally from the left and right ends of the body along the main body dividing surface, and there is no burrs or burr marks near the main body dividing line on the side of the barrel just above the bottom of the container, which is a molded product. Due to the change, glossy spots or colored spots due to factors such as stretch spots, orientation spots, and cooling spots occur.
[0009]
Further, when it is necessary to increase the wall thickness of the parison, even if the blow ratio is close to 3, the above-described gloss spots or color spots are generated.
[0010]
In addition, for example, in the field of cosmetics such as mascara and eyeliner, containers with a small size and a blow ratio of 1.6 or less are often used, and the appearance of the container is an important factor in merchantability. In such a container with a small blow ratio, the width of the pinch-off part that can be taken is the maximum diameter of the bottom surface of the mold cavity, so that it becomes smaller than 1.6 Dp, which is the width of the parison flattened, Since the parison is crushed not only in the pinch-off portion but also in the main body dividing surface in the vicinity of the pinch-off portion, burrs are inevitably generated in the vicinity of the main body dividing line on the side surface of the trunk portion immediately above the bottom.
[0011]
These burr marks, gloss spots, color spots, and the like are serious problems in terms of merchandise, especially in cosmetic containers, but no effective solution to such problems has been shown. Is the current situation. Even if the appearance is improved in the post-treatment process, a long process is required.
[0012]
The present invention was devised to solve the above-described problems of the prior art, and it is a technical problem to suppress the occurrence of burrs in the lateral direction from the right and left ends of the pinch-off portion, particularly at the bottom of the bottom in direct blow. An object of the present invention is to provide a blow molded container having a low blow ratio and excellent appearance without burr marks, gloss spots and color spots on the side of the container near the bottom.
[0013]
[Means for Solving the Problems]
Of the present invention for solving the above technical problem, the means of the invention according to claim 1 is:
Obtained by a direct blow molding method using a split mold that has a main body dividing surface perpendicular to the clamping direction and divided in the front and rear directions. It is a container with a cylindrical mouth portion continuously provided, and a blow ratio in the main body dividing line direction formed by the main body dividing surface of the portion directly above the bottom of the trunk portion is in the range of 1 to 3,
On the bottom bottom surface, a straight pinch-off line formed by a cutting blade disposed on the bottom pinch-off part of the split mold, a pair of main body dividing lines formed on the left and right peripheral edges, the left and right ends of the pinch-off line, and the main body One bottom parting line is formed from a pair of connecting lines that connect the left and right ends of the parting line,
The connecting wire is configured to form a stepped bent portion that is substantially perpendicular to the pinch-off line by the end split surfaces positioned at the left and right ends of the pinch-off portion of the split mold,
The range of formation of burr marks on the bottom bottom surface of the container with the split mold is set to the range from the center of the bottom surface to the stepped bent portion,
It is in.
[0014]
According to the configuration of claim 1, a straight pinch-off line is formed at the center of the bottom bottom surface of the container by a cutting blade disposed on the bottom pinch-off portion of the split mold, and the split mold is formed on the left and right peripheral edges. A pair of main body parting lines are formed by a main body dividing surface perpendicular to the mold clamping direction, and a connecting line connects the pinch-off line and the main body dividing line, and a single bottom parting line is formed on the bottom surface. Yes.
[0015]
In addition, the connection line is configured to form a stepped bent portion that is substantially perpendicular to the pinch-off line by means of the end split surfaces positioned at the left and right ends of the split mold pinch-off portion. That is, the conventional container has a configuration in which a stepped bent portion is inserted between the pinch-off line formed in a straight line and the main body dividing line.
[0016]
In such a container, the front and rear division of the portion below the bottom surface of the mold cavity bottom is at least at the main body division plane, the pinch-off portion, and the left and right ends of the pinch-off portion, and the ends positioned substantially perpendicular to the left-right direction of the pinch-off portion. The split part is blow-molded by a split mold composed of a part split surface, and the end split part is deformed in the lateral direction from the left and right ends of the pinch-off part in the process of deforming the cylindrical parison into a flat shape at the pinch off part. It functions as a weir surface that stops the lateral flow of the flattened resin due to the regulating function or the pressing of the cutting blade portion, and prevents the parison deformation and the resin flow between the main body dividing surfaces.
[0017]
Due to the effect of the stepped bent portion, that is, the end dividing surface as described above, the formation range of burrs generated near the bottom of the container during mold clamping of the split mold in blow molding is from the center of the bottom to the stepped bent portion. It is possible to provide a container free from burr marks, glossy spots, and color spots in the vicinity of the main body parting line on the side surface of the body portion immediately above the bottom.
[0018]
In addition, if the blow ratio in the body parting line direction formed by the body parting surface of the part directly above the bottom part of the trunk part is more than 3, even with conventional blow-molded containers, there are almost no problems in appearance, The effect of the present invention is not significant. Further, in a container having a blow ratio of less than 1, it is difficult to stably hold the parison with a split mold.
[0019]
According to a second aspect of the present invention, there is provided the invention according to the first aspect, wherein the blow ratio is in a range exceeding about 1.6.
[0020]
When the blow ratio exceeds approximately 1.6, the cylindrical parison is first folded into a flat shape at the pinch-off part, and then cut so as to be crushed by the cutting blade. It is possible to prevent the resin from flowing in the lateral direction from the left and right ends of the pinch-off portion due to the pressing at, and the formation of burr marks can be in the range up to the stepped bent portion.
[0021]
According to a third aspect of the present invention, there is provided the invention according to the first aspect, wherein the blow ratio is in the range of about 1.6 or less.
[0022]
Since the deformation of the parison in the lateral direction is restricted at the left and right ends of the pinch-off part, it is possible to crush the parison to a width of 1.6 Dp or less, the blow ratio is 1.6 or less, and just above the bottom part A container free from burrs, gloss spots, and color spots can be provided in the vicinity of the main body parting line on the side of the trunk.
[0023]
According to a fourth aspect of the present invention, in the first, second or third aspect of the invention, the step height of the stepped bent portion is at least twice the thickness of the parison in blow molding.
[0024]
When the blow ratio exceeds approximately 1.6, the cylindrical parison is first folded into a flat shape at the pinch-off part, and its thickness is approximately twice the thickness of the parison. Cut to crush. For this reason, by making the step height of the stepped bent portion at least equivalent to this thickness, it is possible to reliably prevent the resin from horizontally flowing from the left and right ends of the pinch-off portion due to the pressing force by the cutting blade. The burr mark can be reliably formed up to the stepped bend.
[0025]
When the blow ratio is approximately 1.6 or less, the pinch-off portion width needs to be approximately 1.6 Dp or less, and it is necessary to regulate the deformation of the parison in the lateral direction. Although set, this height can be determined according to conditions such as the shape of the container, the blow ratio, the parison diameter and the wall thickness.
[0026]
According to a fifth aspect of the present invention, in the first, second, third or fourth aspect of the invention, the direction of the pinch-off line passing through the center of the bottom bottom surface of the container forms a predetermined center angle with the direction of the main body dividing line. And the left and right ends of the pinch-off line and the left and right ends of the main body dividing line are connected in a substantially straight line to form a connecting line, and the bottom parting line is formed substantially symmetrically with respect to the center of the bottom surface.
[0027]
The structure of claim 5 is formed by inclining the formation direction of the pinch-off line from the direction of the main body dividing line, and by this inclination, the left and right ends of the pinch-off line and the left and right ends of the main body dividing line are positioned in steps. It is the structure which connected in substantially linear form and formed the step-shaped bending part. Further, the step height of the stepped bent portion can be adjusted by the inclination angle, that is, the center angle.
[0028]
According to the above configuration, the bottom parting line can be formed simply, that is, the parting plane below the bottom part of the mold cavity can be formed in a simple shape, and the pinch-off line is close to the full width of the bottom diameter. Therefore, a container having a lower blow ratio can be easily provided.
[0029]
According to a sixth aspect of the present invention, in the fifth aspect of the invention, the center angle is set to 45 ° or less.
[0030]
The above-described configuration determines the upper limit of the center angle. However, if the center angle is too large, that is, if the pinch-off line is inclined too much from the direction of the body parting line, the surface is greatly inclined in the blow-molding pinch-off process. In this case, the flat crushing of the parison is performed, and the pinch-off process cannot be smoothly achieved.
[0031]
As described above, the step height of the stepped bend is adjusted by the center angle, so the lower limit of the center angle is the required step height, the size of the container to be molded, the thickness of the parison, etc. Therefore, a value that can be used as a guideline geometrically can be determined.
[0032]
According to a seventh aspect of the present invention, in the first, second, third, or fourth aspect of the invention, the direction of the pinch-off line passing through the center of the bottom bottom surface of the container is the same as the direction of the main body dividing line. The step-shaped bent portion is formed substantially symmetrically from the left and right ends of the line.
[0033]
In the above-described configuration according to the seventh aspect, since the crushing of the parison by the pinch-off portion is achieved on a plane perpendicular to the mold clamping direction of the split mold, the pinch-off process can be achieved more stably. The step height of the bent portion can be made sufficiently high, and the deformation of the parison in the left-right direction can be reliably regulated.
[0034]
The means of the invention described in claim 8 is used as a primary molded product in the invention described in claim 1, 2, 3, 4, 5, 6 or 7, and is molded into a biaxial stretch blow molded container. It is in.
[0035]
According to the above configuration of claim 8, a biaxial stretch blow molded container can be obtained by using a direct blow molded container as a primary molded product, a so-called preform, to obtain a biaxial stretch blow molded container. Because it is possible to form a preform that does not exist in the injection-molded preform without considering the undercut property, the biaxial stretch blow container has various shapes and has a uniform thickness and stretch. In addition, it is possible to easily manufacture a laminated type biaxially stretched blow container by multilayer forming a parison.
[0036]
According to a ninth aspect of the invention, there is provided the invention according to the first, second, third, fourth, fifth, sixth, seventh or eighth aspect, wherein the wall has a laminated structure.
[0037]
According to the above-described configuration of the ninth aspect, the wall can be made into a laminated structure, and a container capable of effectively exhibiting desired physical properties and characteristics can be reliably obtained. Formation can be easily achieved.
[0038]
According to a tenth aspect of the present invention, there is provided a laminated structure including at least the outer layer and an inner layer formed of a synthetic resin having low compatibility with the synthetic resin forming the outer layer. To make up.
[0039]
According to the structure of claim 10, a container comprising a synthetic resin outer layer forming an outer shell and a synthetic resin inner layer forming an inner bag, which is detachably laminated with the outer layer is formed. Can be used as a delamination container.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 show a first embodiment of a blow-molded container according to the present invention, which has a shape in which a mouth portion 2 is continuously provided above a cylindrical barrel portion 3 and has a height of 120 mm and an outer diameter of the barrel portion 3 of 40 mm. The blow ratio of the body part 3 is 1.8.
[0041]
As shown in the bottom view of FIG. 2, on the bottom surface 5, the pinch-off line 14 formed at the center is formed with a center angle α inclined in the direction of the pair of main body dividing lines 13 positioned at the left and right peripheral edges, The left and right ends of the pinch-off line 14 and the left and right ends of the main body dividing line 13 are connected by a connecting line 16 in a substantially straight line along a circular fitting line 18 to be described later, so that one bottom dividing line 17 is connected to the bottom surface 5. It is formed to be axially symmetric with respect to the center.
[0042]
Further, the connecting line 16 forms a stepped bent portion 15 substantially perpendicular to the pinch-off line 14, and as will be described later, in the blow molding of the container of the first embodiment, the flat push of the parison P by the pinch-off portion 105 is performed. Since burr formation by crushing is limited below the pinch-off portion 105, the burr mark in the container of this embodiment is in the range from the center of the bottom surface to the step-shaped refracting portion 15, and further, the side surface of the body portion 3 just above the bottom portion 4 In the vicinity of the position of the main body parting line 13, the container has no appearance defects such as gloss spots and color spots.
[0043]
3 to 5 show an example of a blow molding split mold for molding the container of the first embodiment. FIG. 3 is an overall perspective view of the rear part mold 101b of the pair of split molds 101 divided into the front and rear, and one front part mold 101a is substantially axisymmetric with respect to the rear part mold 101b. Shape.
[0044]
Further, in the portion below the bottom surface 103 and the bottom surface 104 of the mold cavity 102, the dividing surface is formed by a stepped surface, and the arrangement direction of the cutting blade 106 is inclined at a certain angle from the main body dividing surface 111. A pinch-off portion 105 is formed.
[0045]
Further, an end split surface 112 is formed and arranged at the left and right ends of the pinch-off portion 105 so as to be substantially perpendicular to the left and right direction of the biting blade 106, and as shown in FIG. It is recessed from the dividing surface 111 and protrudes from the main body dividing surface 111 at the right end.
[0046]
In this embodiment, a part of the mold below the bottom surface 104 of the bottom 103 of the mold cavity 102 is formed by a separate substantially semi-cylindrical bottom block body 107 and is assembled and assembled. This combination facilitates the manufacture of the split mold, enables degassing during blow molding along the combination surface, and the vicinity of the pinch-off portion 105 including the cutting blade 106 by changing the metal material There is an advantage that the wear resistance can be improved.
[0047]
Due to the configuration of the split mold 101 described above, when the split mold 101 is in a closed state, a linear pinch-off line 114 formed on the bottom 103 bottom surface 104 of the mold cavity 102 by the butting of the cutting blade 106 is provided. , A pair of main body dividing lines 113 formed by the main body dividing surface 111 located at the left and right peripheral edge portions of the bottom surface 104, and a pair of connecting lines 116 connecting the left and right ends of the pinch-off line 114 and the left and right ends of the main body dividing line 113. A single bottom parting line 117 is formed so as to be axially symmetric with respect to the center of the bottom surface 104. (See Figure 4)
[0048]
And the marks of the pinch-off line 114, the main body dividing line 113, the connecting line 116 and the bottom parting line 117 formed on the bottom surface 104 of the mold cavity 102 remain on the bottom surface 5 of the container 1, and the pinch-off line 14 and the main body are respectively formed on the bottom surface 5. A dividing line 13, a connecting line 16, and a bottom dividing line 17 are formed.
[0049]
By fitting the bottom block body 107, a fitting line 118 is formed on the bottom 3 bottom surface 4 of the mold cavity 102, and a mark of the fitting line 118 remains on the bottom 4 bottom surface 5 of the container 1, and the bottom surface 5 In the first embodiment, the connecting line 16 is formed along the arc of the fitting line 18 so that the connecting line 16 is not conspicuous. Yes.
[0050]
FIG. 5 is an explanatory view showing a pinch-off process by the split mold 101 shown in FIGS. 3 and 4 in a plane sectional view. The parison P is sandwiched between the pinch-off portions 105 provided with the biting blades 106 as the mold clamping progresses, and is crushed flat. However, the stepped bent portions 115 formed at the left and right ends of the pinch-off line 114 are pinched off. Since the end dividing surfaces 112 formed at the left and right ends of the portion 105 serve as a weir, it is possible to prevent the flow of the flattened resin to the body dividing surface 111 in the left-right direction due to the pressing of the cutting blade 106. it can.
[0051]
As can be seen from FIGS. 4 and 5, the main body dividing surface 111 in which the direction of the cutting blade 106 is perpendicular to the clamping direction of the split mold 101 (the direction of the white arrow in FIG. 5A). Although the center angle α is deviated from this direction, the pinch-off process can be smoothly achieved if α is in the range of up to 45 °.
[0052]
In addition, by making the step height h of the step-shaped bent portion 115 formed from the end portion dividing surface 112 at least twice the thickness of the parison P, the flow of the resin to the lateral direction and the main body dividing surface 111 is ensured. Can be blocked. (See FIG. 5 (b))
[0053]
FIG. 6 shows a front view and a bottom view of an example of a conventional container for comparison with the first embodiment (hereinafter referred to as a first comparative example). The container of the first comparative example has the same shape as that of the first example, but the pinch-off line 14 is formed along the direction of the main body dividing line 13 on the bottom surface 5 and the burr mark is formed on the bottom surface. As a result, gloss spots and color spots are generated in the vicinity of the position of the body parting line 13 on the side surface of the body part 3 immediately above the bottom part 4 (the position of the white arrow in FIG. 6A).
[0054]
FIG. 7 shows an example of a conventional split mold, that is, a split mold 101 for molding the container of the first comparative example. As described above, the conventional split mold 101 is divided into two parts in the front and rear directions by the main body dividing surface 111 perpendicular to the clamping direction (the direction of the white arrow in FIG. 7), and along the main body dividing surface 111. A pinch-off portion 105 is formed by disposing the cutting blade 106.
[0055]
FIG. 8 is an explanatory view showing a pinch-off process by the split mold 111 of FIG. When the mold is closed (see FIG. 8C), the pinch-off line 114 and the main body dividing line 113 are formed in a straight line, so that the resin crushed in the pinch-off process also flows in the left-right direction and the main body is divided. It also flows into the surface 111, and causes burr marks, gloss spots, and color spots on the container 1.
[0056]
FIG. 9 is a bottom view of the second embodiment of the blow molded container of the present invention. The container of the second embodiment has the same shape as that of the first embodiment, but the blow ratio is 2, and on the bottom surface 5, the pinch-off line 14 formed at the center is a pair of left and right peripheral edges. It is formed on the same line as the main body dividing line 13, and the left and right ends of the pinch-off line 14 and the left and right ends of the main body dividing line 13 are connected by a connecting line 16 having an ear shape. Are formed in a symmetrical shape.
[0057]
Further, the connecting line 16 is formed at a right angle at the right and left ends of the pinch-off line 14 and has a stepped bent portion 15 having a step height h. As will be described later, in the blow molding of the container of the second embodiment, A burr mark due to burr formation at the time of crushing the parison P at the portion 105 is a range from the center of the bottom surface 5 to the step-shaped refracting portion 15, and the main body parting line 13 on the side surface of the body portion 3 immediately above the bottom portion 4. It is a container with no appearance defects such as burr marks, gloss spots, and color spots in the vicinity of the position.
[0058]
In this second embodiment, the length of the pinch-off line 14 in the left-right direction is approximately 1.2 Dp, which is shorter than the width 1.6 Dp where the parison is flattened. Since the deformation in the direction is restricted by a part of the split mold surface, the burr mark is in the range up to the step-shaped bent portion 15 as described above.
[0059]
10-13 shows the split mold 101 for shape | molding the container 1 of the 2nd Example. FIGS. 10 and 11 are overall perspective views of the rear mold 101b and the front mold 101a of the pair of split molds 101 divided in the front and rear directions, respectively.
[0060]
The split mold 101 is also configured by a surface where the split surface is bent stepwise in the portion below the bottom 103 bottom surface 104 of the mold cavity 102. However, the arrangement direction of the cutting blade 106 is the same as that of the conventional split mold. Similarly, a pinch-off portion 105 is formed as a direction along the main body dividing surface 111.
[0061]
In addition, end split surfaces 112 are formed and arranged at right and left ends of the pinch-off portion 105 substantially perpendicularly to the left-right direction of the cutting blade 106, and at the left and right ends of the pinch-off portion 105 as shown in FIGS. The rear split mold 101b is formed with an ear-shaped recess 108b from the main body split face, and the front split mold 101a is formed with a protrusion 108a. The mold clamping of the split mold 101 is achieved while fitting into the recess 108b.
[0062]
Due to the configuration of the split mold 101 described above, when the split mold 101 is in a closed state, a linear pinch-off line 114 formed on the bottom 103 bottom surface 104 of the mold cavity 102 by the butting of the cutting blade 106 is provided. A pair of body parting lines 113 formed by the body parting surfaces 111 located at the left and right peripheral edge portions of the bottom surface 104, and a pair of ear-like shapes connecting the left and right ends of the pinch-off line 114 and the right and left ends of the body parting lines 113. One bottom parting line 117 is formed from the connecting line 116 so as to be axially symmetric with respect to the center of the bottom surface 104. (See Figure 12)
[0063]
Traces of the pinch-off line 114, the main body dividing line 113 and the connecting line 116 on the bottom surface 104 of the mold cavity 102 remain on the bottom surface 5 of the container 1, and the pinch-off line 14, the main body dividing line 13 and the connecting line 16 are formed on the bottom surface 5, respectively. Is done.
[0064]
Also, in this split mold, a part of the mold below the bottom surface 103 of the bottom 103 of the mold cavity 102 is formed by separate block bodies 107a and 107b and assembled.
[0065]
FIG. 13 is an explanatory view showing a pinch-off process by the split mold 101 of FIGS. The cylindrical parison P is crushed into a flat shape and deformed into an oval shape. However, when the flat parison P is in a certain flat state, as shown in FIG. 13B, an ear shape of the front split mold 101a is formed. The end dividing surface 112 that forms a part of the protrusion 108a having the shape of the shape of the projection 108a functions as a weir surface, and further lateral deformation is prevented. Thereafter, the left and right end dividing surfaces The parison P is crushed within the width of 112, and the excess resin is forced to flow below the biting blade 106.
[0066]
In the configuration of the container according to the second embodiment, the pinch-off process is achieved by the pinch-off portion 105 in a plane perpendicular to the clamping direction of the split mold 101, so that the pinch-off process can be achieved more stably. In addition, the step height of the stepped bent portion 15 can be made sufficiently high, and the width of the pinch-off line 14 can be sufficiently made 1.6 Dp or less as described above.
[0067]
FIG. 14 is a front view and a bottom view of a third embodiment of the blow molded container of the present invention. It is a small container 1 obtained by direct blow molding, and has a shape in which a cylindrical body 3 is provided above a bottom 4 and a cylindrical mouth 2 is provided above the bottom. A cap having a brush with a shaft is assembled and fixed by screwing and used for a container body for mascara or eyeliner. In order to clarify the comparison with the second comparative example to be described later, FIG. 14 and FIG. 15 to be described later show a state before separating the burr 7 that is a portion where excess resin protrudes in the vicinity of the pinch-off portion. Is.
[0068]
The diameter of the trunk portion 3 of the container 1 is 15 mm and the height is 75 mm. A bottom parting line 17 having the same shape and configuration as the first embodiment is formed on the bottom surface of the bottom part 4.
[0069]
This container 1 is blow molded using a parison having an outer diameter of 10 mm, and the blow ratio from the body 3 to the bottom 4 is as small as 1.5 (15 mm / 10 mm). As can be seen, the burr mark is a range up to the stepped bent part 15 and is a container having no appearance defect such as a burr mark, a glossy spot, and a color spot in the vicinity of the position of the main body dividing line 13 on the side surface of the body part 3 immediately above the bottom part 4. is there.
[0070]
FIG. 15 is a second comparative example for comparing the third embodiment with a container obtained by a conventional split mold, and the shape of the container 1 is the same as that of the third embodiment. When a container 1 having a blow ratio smaller than 1.5 and 1.6 is formed with a conventional split mold, the burr 7 is not only the pinch-off line 14 part but also the body parting line of the body part 3 as shown in the shape of the burr 7. As a result, burr marks are inevitably formed also in the vicinity of the position of the main body parting line 13 on the side surface of the body part 3 immediately above the bottom part 4.
[0071]
FIG. 16 is a front view and a bottom view of a fourth embodiment of the blow molded container of the present invention. A small container 1 obtained by direct blow molding. For example, a cap with a small hand pump attached to the mouth 2 is assembled and fixed by screwing, and is used as a container body of a liquid cosmetic dispensing container. Is.
[0072]
The diameter of the barrel 3 of the container 1 is 23 mm and the height is 75 mm. A bottom parting line 17 having the same shape and configuration as in the first embodiment is formed on the bottom surface of the bottom part 4. The step height h of the stepped bent part 15 is 3 mm, and the center angle α is 15 °.
[0073]
This container 1 is blow-molded using a parison having an outer diameter of 19 mm. The blow ratio from the body 3 to the bottom 4 is as small as 1.2 (23 mm / 19 mm), but the burr mark is a stepped bent portion. This is a container having no appearance defects such as burr marks, gloss spots, and color spots in the vicinity of the position of the main body parting line 13 on the side surface of the body part 3 immediately above the bottom part 4.
[0074]
FIG. 17 shows a fifth embodiment of the blow molded container of the present invention, which is a test tubular container 1. The neck ring 8 is attached, the height is 105 mm, the diameter of the body part 3 is reduced from 24 mm at the upper end to 22 mm at the substantially central height position, and the bottom part 4 has a hemispherical shell shape with an outer diameter of 18 mm. The blow ratio directly above the bottom 4 of the body 3 is 1.2. Further, a bottom parting line 17 having substantially the same shape as that of the first embodiment is formed on the bottom surface 5, and the formation range is a range up to the stepped bent portion 15 of the hemispherical bottom surface 5.
[0075]
FIG. 18 shows a sixth embodiment of the blow-molded container of the present invention, in which the container wall of the fifth embodiment is multilayered. The container 1 shown in FIG. 19 is obtained by biaxially stretching blow-molding the container 1 of the fifth embodiment as a primary molded product 9, a so-called preform.
[0076]
The direct blow molded container can be easily formed into a laminated structure by forming a parison in multiple layers, and the laminated structure such as the wall thickness ratio can be achieved with high precision. As a result, it is possible to easily manufacture a laminated type biaxial stretch blow molded container.
[0077]
In direct blow molding, when air blows, a core guide having an air nozzle is inserted from above the parison. At this time, the upper end surface of the mouth can be sealed with the inner layer. When used, for example, even when a water-absorbing resin such as ethylene vinyl alcohol copolymer or nylon is used for the intermediate layer, it is possible to prevent moisture from entering from the upper end surface of the mouth, and biaxial stretch blow molding Preservation management of the previous preform becomes easy. Examples of specific laminated structures are shown below.
[0078]
The first example of the primary molded article 9 having a laminated structure is composed of a combination of a layer using PET and a layer using PEN, and the first is an outer layer 1a made of PET and an inner layer 1c made of PEN. No. 2 is a combination of an outer layer 1a made of PET, an intermediate layer 1b made of PEN and an inner layer 1c made of PET, No. 3 is a combination of an outer layer 1a made of PEN and an inner layer 1c made of PET, No. 4 Is a combination of an outer layer 1a made of PEN, an intermediate layer 1b made of PET, and an inner layer 1c made of PEN. In any combination, an adhesive layer 1d may be provided between the layers.
[0079]
In the first example, part 1 and part 4 use PEN for the inner layer 1c, so that a container having high chemical resistance (alkali resistance) can be obtained. All the configurations of the first example can obtain an ultraviolet blocking function capable of cutting ultraviolet rays of 370 nm or less by setting the thickness of PEN to 1 to 20%.
[0080]
A second example of the primary molded article 9 having a laminated structure is constituted by a combination of an outer layer 1a and an inner layer 1c using PET, and an intermediate layer 1b using a gas barrier resin. The intermediate layer 1b is made of an ethylene vinyl alcohol copolymer, No. 2 is made of an xylylene group-containing polyamide (MXD nylon), and No. 3 is an intermediate layer 1b of polyacrylonitrile. In this second example, a container 1 having barrier properties such as oxygen and carbon dioxide that are insufficient for PET alone can be obtained. The container 1 without delamination can be obtained reliably.
[0081]
The third example of the primary molded article 9 having a laminated structure is to join an outer layer 1a using polyethylene or polypropylene and an inner layer 1c using an ethylene vinyl alcohol copolymer or PET resin with an adhesive layer 1d. Therefore, the container 1 does not absorb the active ingredients such as limonene and vitamins stored in the container 1.
[0082]
The fourth example of the primary molded article 9 having a laminated structure is an outer layer 1a using polyethylene or polypropylene, an intermediate layer 1b using a xylylene group-containing polyamide as a gas barrier resin, and an inner side using polyethylene or polypropylene. The layer 1c is formed by bonding with an adhesive layer 1d, and the container 1 exhibits high oxygen barrier properties.
[0083]
A fifth example of the primary molded product 9 having a laminated structure is configured by joining an outer layer 1a using nylon 6 and an inner layer 1c using polyethylene or polypropylene with an adhesive layer 1d. A thin-walled container 1 having a piercing strength and a high surface gloss can be provided.
[0084]
In the sixth example of the primary molded product 9 having a laminated structure, a laminated structure is constituted by an outer layer 1a and an inner layer 1c using a PET virgin resin material, and an intermediate layer 1b using a recycled PET resin material. Therefore, the recycled resin material can be safely used in a state in which the layer thickness is easily controlled. Moreover, it can be handled as a PET single substance at the time of fractional collection.
[0085]
A seventh example of the primary molded article 9 having a laminated structure is an outer layer 1a in which an antistatic agent is added to PET, an intermediate layer 1b in which an ultraviolet absorber is added to PET, and an inner side using a PET virgin resin material. A layered structure is formed from the layer 1c, and since it is added to the intermediate layer with an effective antistatic effect, there is no loss due to bleeding out of the UV absorber, and the contents are safe regardless of the addition of the additive Storage can be obtained. The resin that can be used in this example is not limited to PET, and the same effect is exhibited with other resins.
[0086]
An eighth example of the primary molded product 9 having a laminated structure is an outer layer 1a formed of a synthetic resin material such as polyethylene, polypropylene, and PET, and formed as an outer shell body having a necessary self-shape retention capability; A synthetic resin material having low compatibility with the outer layer 1a, such as nylon, ethylene vinyl alcohol copolymer, polyethylene terephthalate, etc., and a laminated structure composed of an inner layer 1c that is molded into a flexible bag shape Thus, a delamination container can be provided.
[0087]
A ninth example of the primary molded article 9 having a laminated structure is one in which the outer layer 1a is made of glazed or matt polypropylene or polyethylene, and the appearance of the product is easily made glazed or matt. can do.
[0088]
The tenth example of the primary molded article 9 having a laminated structure is a laminated structure composed of an outer layer 1a made of an ethylene vinyl alcohol copolymer or PET and an inner layer 1c made of a polyolefin resin. Can be made.
[0089]
【The invention's effect】
Since the present invention has the above-described configuration, the following effects can be obtained.
In the first aspect of the invention, the burr is formed on the bottom surface by adopting a configuration in which a stepped bent portion is inserted between the pinch-off line formed in a straight line on the bottom surface and the main body dividing line in the conventional container. It is possible to provide a container having a low blow ratio and free from burrs, gloss spots, and color spots on the side surface of the body portion immediately above the bottom.
[0090]
In the invention of claim 2, the resin can be prevented from flowing laterally from the left and right ends of the pinch-off portion due to pressing at the cutting blade portion, and the formation of burr marks can be extended to the stepped bent portion. can do.
[0091]
In the invention of claim 3, it is possible to provide a container having a blow ratio of about 1.6 or less and having no burr marks, gloss spots, and color spots in the vicinity of the main body parting line on the side surface of the trunk portion immediately above the bottom. .
[0092]
In the invention of claim 4, by making the step height of the step-shaped bent portion at least twice the thickness of the parison in blow molding, particularly when the blow ratio exceeds approximately 1.6, It is possible to reliably prevent the flow of resin from the left and right ends of the pinch-off portion due to the pressing force generated by the cutting blade.
[0093]
In the invention of claim 5, the stepped bent portion is easily formed at the left and right ends of the pinch-off line by setting the direction of the pinch-off line to a direction that forms a predetermined center angle with the direction of the main body dividing line. In other words, it is possible to form a split surface of the portion below the bottom bottom surface of the cavity of the split mold with a simple shape, and it is possible to form a pinch-off line over the entire width of the bottom surface diameter. A container having a low blow ratio can be easily provided.
[0094]
In the invention of claim 6, the pinch-off process can be achieved smoothly by setting the center angle to 45 ° or less.
[0095]
In the invention according to claim 7, the pinch-off process is more stably achieved by setting the direction of the pinch-off line to be the same as the direction of the main body dividing line and forming the step-like bent portions substantially symmetrically. In addition, the step height of the stepped bent portion can be made sufficiently high, and the deformation of the parison in the left-right direction can be reliably controlled.
[0096]
In the invention of claim 8, since the biaxial stretch blow molding is performed using the direct blow molding container as a preform, a preform having a shape not found in the injection molding preform can be formed, and has various shapes. In addition, a biaxial stretch blow molded container having a uniform wall thickness and stretch ratio can be provided, and a multilayer type biaxial stretch blow molded product can be easily manufactured by multilayer forming the parison.
[0097]
According to the ninth aspect of the present invention, it is possible to easily provide a container that can effectively exhibit desired physical properties and characteristics by forming a wall into a laminated structure.
[0098]
In a tenth aspect of the present invention, a container comprising an outer layer made of a synthetic resin that forms a fixed outer shell, and an inner layer made of a synthetic resin that is detachably laminated with the outer layer and forms an inner bag. Can be used as a delamination container.
[Brief description of the drawings]
FIG. 1 is a front view showing a first embodiment of a blow molded container of the present invention.
FIG. 2 is a bottom view of the container of FIG.
FIG. 3 is an overall perspective view showing a rear mold of the mold for molding the container of FIG. 1;
4 is a cross-sectional plan view taken along the line AA in FIG. 3 in the mold closed state of the split mold in FIG. 3;
5 is an explanatory view showing a pinch-off process by the split mold of FIG. 3 in a plane sectional view similar to FIG.
FIG. 6 is a front view and a bottom view showing a container of a first comparative example.
7 is an overall perspective view showing a rear mold of the mold for molding the container of FIG. 6. FIG.
8 is an explanatory view showing the pinch-off process by the split mold of FIG. 6 in the same manner as FIG.
FIG. 9 is a bottom view showing a second embodiment of the blow molded container of the present invention.
10 is an overall perspective view showing a rear part mold among the molds for molding the container of FIG. 9. FIG.
11 is an overall perspective view showing a front part mold among the molds for molding the container of FIG. 9. FIG.
12 is a cross-sectional plan view taken along the line BB in FIG. 10 in the mold-closed state of the split mold shown in FIGS. 10 and 11. FIG.
13 is an explanatory view showing a pinch-off process by the split mold shown in FIGS. 10 and 11 in a plane sectional view similar to FIG.
FIG. 14 is a front view and a bottom view showing a third embodiment of the blow molded container of the present invention.
FIG. 15 is a front view and a bottom view showing a container of a second comparative example.
FIG. 16 is a front view and a bottom view showing a fourth embodiment of the blow-molded container of the present invention.
FIG. 17 is a front view and a bottom view showing a fifth embodiment of the blow-molded container of the present invention.
FIG. 18 is a partially longitudinal front view showing a sixth embodiment of the blow molded container of the present invention.
FIG. 19 is a half longitudinal front view showing an example of a biaxial stretch blow-molded container obtained by using the container of FIG. 18 as a primary molded product.
FIG. 20 is an explanatory view showing a mold clamping process of blow molding.
[Explanation of symbols]
1; mouth
1a; outer layer
1b: intermediate layer
1c; inner layer
1d: adhesive layer
2; mouth
3; trunk
4; Bottom
5; Bottom
7; Bali
8; Neck ring
9; Primary molded product
13; Body parting line
14 ： Pinch-off line
15; stepped bend
16; connecting line
17; bottom parting line
18; mating wire
101; split mold
101a; front split mold
101b; rear split mold
102; mold cavity
103; bottom
104; bottom
105; pinch-off part
106; biting blade
107; bottom block body
107a; bottom block body
107b; bottom block body
108a; protrusion
108b; recess
111; main body dividing surface
112; end dividing surface
113; body parting line
114; pinch-off line
115; stepped bend
116; connecting line
117; bottom parting line
118; grounding wire
122; Parison cutter
121; Extruder
P: Parison
α: Center angle
h; Step height

Claims (10)

It has a main body dividing surface (111) perpendicular to the clamping direction, and is obtained by a direct blow molding method using a split mold (101) divided back and forth, and a cylindrical body above the bottom (4) (3) is a continuous shape and a cylindrical mouth portion (2) is continuously provided above the trunk portion (3), and the main body dividing surface of the bottom portion (4) immediately above the trunk portion (3) (111) is a container (1) having a blow ratio in the direction of the main body parting line (13) in the range of 1 to 3, and the bottom mold (5) has the split mold ( 101) a straight pinch-off line (14) formed by a cutting blade (106) disposed on a bottom pinch-off part (105) of the bottom part, and a pair of the main body dividing lines (13) formed on the left and right peripheral parts. A pair of connecting lines (16) connecting the left and right ends of the pinch-off line (14) and the left and right ends of the main body dividing line (13), respectively, to form a single bottom dividing line (17), The line (16) is positioned at the left and right ends of the pinch-off part (105). The end split surface (112) forms the pinch-off line (14) and a stepped bent portion (15) substantially perpendicular to the bottom part (4) bottom surface (5) by the split mold (101). ) In which the burr mark is formed in the range from the center of the bottom surface (5) to the stepped bent portion (15). The blow molded container according to claim 1, wherein the blow ratio is in a range exceeding about 1.6. The blow molded container according to claim 1, wherein the blow ratio is in a range of about 1.6 or less. The blow molded container according to claim 1, 2 or 3, wherein the step height (h) of the step bent portion (15) is at least approximately twice the thickness of the parison (P) in blow molding. The direction of the pinch-off line (14) passing through the center of the bottom (4) bottom surface (5) is a direction that forms a predetermined center angle (α) with the direction of the main body dividing line (13), and the pinch-off line (14) The left and right ends and the left and right ends of the main body parting line (13) are connected in a substantially straight line to form a connecting line (16), and the bottom parting line (17) is formed substantially symmetrically about the center of the bottom surface (5) A blow molded container according to claim 1, 2, 3 or 4. The blow molded container according to claim 5, wherein the central angle (α) is 45 ° or less. The direction of the pinch-off line (14) passing through the center of the bottom (4) bottom surface (5) is the same direction as the direction of the main body dividing line (13), and is stepped substantially symmetrically from the left and right ends of the pinch-off line (14). The blow-molded container according to claim 1, 2, 3, or 4, wherein a bent portion (15) is formed. The blow-molded container according to claim 1, 2, 3, 4, 5, 6 or 7, which is used as a primary molded article (9) and molded into a biaxial stretch blow-molded container. The blow-molded container according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the wall forming the container has a laminated structure. The laminated structure comprises at least an outer layer (1a) and an inner layer (1c) formed from a synthetic resin having low compatibility with the synthetic resin forming the outer layer (1a). Blow molded container.

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