JP4846541B2 - Injection blow molding bottle and its mold - Google Patents

Description

  The present invention relates to an injection blow molded bottle and a mold for producing the injection blow molded bottle. More particularly, the present invention relates to a bottomed, generally cylindrical injection blow molded bottle having a feature at the bottom and a mold thereof.

  A bottomed shaped bottle filled with liquid food such as drinking water is easy to carry or easy to handle, especially if the user of the bottle is an infant or elderly person. In this case, it is desirable to be lightweight. Conventionally, plastic bottles have been used more favorably than glass bottles. In particular, polycarbonate has been widely used as a molding material for plastic molding bottles because of its excellent moldability and transparency. However, in recent years, elution of environmental hormones caused by polycarbonate has become a problem, and more safety has been achieved. High polyethersulfone is beginning to be used as a molding material to replace polycarbonate.

  Patent Document 1 discloses a baby bottle using such polyethersulfone as a molding material. Since this polyethersulfone does not have a bisphenol skeleton, there is no elution of environmental hormones, and it is excellent in heat resistance, thermal stability and oxidation stability as compared with polycarbonate. However, polyethersulfone is inferior in impact resistance, and as a molding material for molding bottles especially for infants or elderly people, it is vulnerable to frequent drop impacts, and damage to the molding bottle and occurrence of cracks. It cannot be suppressed sufficiently.

In order to improve the impact resistance of such a polyethersulfone, for example, Patent Document 2 proposes a baby bottle having a raised bottom shape in which the shape of the bottle bottom is curved in a spherical shape upward. However, even if the shape of the bottle bottom is changed in this way, the molded bottle made of polyethersulfone still has a problem that it is difficult to prevent breakage of the bottom and occurrence of cracks.
Japanese Patent No. 3506646 JP 2001-29433 A

  In particular, in the case of a bottomed molded bottle filled with liquid food such as a baby bottle, the impact during dropping tends to concentrate on the bottom, and in conventional molded bottles made of polyethersulfone, damage to the bottom and cracked bottom The occurrence of cracks cannot be avoided sufficiently.

  Accordingly, it is an object of the present invention to provide a bottomed shaped bottle, in particular, a shaped bottle with further enhanced impact resistance at the bottom, and a mold for forming the shaped bottle.

The injection blow molded bottle of the present invention is a bottomed substantially cylindrical injection blow molded bottle, and the molded bottle is made of a polyphenylsulfone resin having a repeating unit represented by the following formula (1):
The bottom outer wall of the molding bottle forms a concave portion that is raised to a gentle spherical shape from the outer peripheral side toward the center of the bottom, and
A concentric central sedimentation part is formed from the surface of the central part of the spherical concave part toward the upper part,
Furthermore, on the outside of the concentric central settling part, an annular outer settling part is formed via a concentric convex inner outer ring part,
And the bottom part inner surface wall of this shaping | molding bottle forms the smooth spherical surface without an unevenness | corrugation, It is characterized by the above-mentioned.

  And the said convex inner outer ring | wheel part protrudes concentrically toward the lower part from the center part surface of the said spherical recessed part, Furthermore, it is a lower part from the center part surface of the said spherical recessed part on the outer side of the said outer sedimentation part. It is preferable that a convex outer outer ring portion projecting concentrically is formed.

In addition, the injection blow-molded bottle of the present invention assumes a virtual bottom curve that is a smooth spherical shape without forming the central sedimentation portion and the outer sedimentation portion in the recess,
The most depressed position in the concentric central settling portion formed from the center surface of the spherical concave portion of the bottom outer surface wall of the molding bottle toward the top is 0.38 to 0.43 mm in height from the virtual bottom curve. The position of
In addition, the most depressed position in the annular outer settling portion formed through the concentric outer ring portion on the outer side of the concentric central settling portion is a position having a height of 0.28 to 0.33 mm from the virtual bottom curve. It is preferable that

The injection blow molded bottle of the present invention can be suitably used as a baby bottle, for example.
The mold used to mold the bottom of the bottomed substantially cylindrical shaped bottle of the present invention is a mold used to mold the bottomed substantially cylindrical shaped bottle,
The bottom outer surface wall of the mold forms a convex portion raised to a gentle spherical shape from the outer peripheral side toward the bottom center,
A concentric central protuberance is formed from the center surface of the spherical convex portion toward the top,
Furthermore, an annular outer raised portion is formed outside the concentric central raised portion via a concentric concave inner outer ring portion.

  The concave inner outer ring portion is concentrically settled from the surface of the central portion of the spherical convex portion toward the lower portion, and further, on the outer side of the outer protruding portion, the spherical convex portion. It is preferable that a concave outer ring portion that is concentrically settled from the center surface toward the lower portion is formed.

Further, the mold used for molding the bottom of the bottomed substantially cylindrical molding bottle of the present invention has a smooth spherical shape without forming the central raised portion and the outer raised portion on the convex portion. Assuming a hypothetical bottom curve,
The most raised position of the concentric central bulge formed from the center surface of the spherical convex portion of the bottom outer surface wall of the mold toward the top is 0.38-0. 43mm position,
In addition, the most prominent position of the annular outer bulge formed on the outer side of the concentric central bulge via the concentric outer ring portion is a position having a height of 0.28 to 0.33 mm from the virtual bottom curve. It is preferable that

  As described above, in the present invention, the use of polyphenylsulfone, which is superior in impact resistance to polyethersulfone, and imparting a specific shape to the bottom thereof, the weld around the gate trace that causes cracking or breakage is provided. The bottomed substantially cylindrical shaped bottle excellent in drop impact resistance can be realized. That is, the injection blow-molded bottle of the present invention is preferably capable of preventing cracking of the bottle bottom accompanying the occurrence of welds that are easily formed around the gate of the parison used during injection blow molding, using a predetermined bottom mold. . Although the molded bottle of the present invention is formed using polyphenylsulfone which is resistant to impact, it is possible to suppress the occurrence of weld which is a potential starting point of cracks generated in this molded bottle made of polyphenylsulfone. The excellent impact resistance of polyphenylsulfone can be used effectively.

  According to the molded bottle of the present invention, it is made of polyphenylsulfone resin excellent in impact resistance, and a specific shape is given to the bottom of the molded bottle, so that it is more resistant to drop impact than conventional polyethersulfone. An excellent molding bottle, particularly a molding bottle suitable for injection blow molding can be obtained.

  Moreover, according to the metal mold | die of this invention, since a specific shape is provided to the bottom part of substantially cylindrical shape with a bottom, the shaping | molding bottle excellent in the impact strength in a bottom part can be obtained.

The blow molded bottle of the present invention will be described in detail below with reference to the drawings.
1 and 2 are sectional views of a bottomed substantially cylindrical injection blow molded bottle of the present invention (hereinafter also referred to as “molded bottle of the present invention”). In FIG. 1 and FIG. 2, the example in the case of being a baby bottle is shown as a shaping | molding bottle of this invention.

  For example, as shown in FIG. 1A, a baby bottle that is a preferred embodiment of the molded bottle of the present invention comprises a protective cap 10, a nursing nipple 11, a cap 12, and a bottle body 16. And having a substantially cylindrical shape with a bottom. That is, the bottle main body 16 of the present invention has a neck portion 14, a body portion 18, and a bottom portion 20, and the body portion 18 extends from the upper shoulder 17 to form the body portion 18. 18 and has a bottom portion 20 formed through a lower shoulder 19. The body portion 18 has a substantially cylindrical shape, that is, a cross-sectional shape of a circle, an ellipse, or a substantially square shape with rounded corners. Presents. The bottom portion 20 is warped upward, and as shown in a rear view (B) of the bottom portion 20, a central sedimentation portion 21 is formed on the central surface of the bottom portion 20, and An annular outer settling portion 22 is formed outside. A convex inner outer ring portion 24 is formed outside the central sedimentation portion 21 and inside the outer sedimentation portion 22, and a convex outer outer ring portion 25 is formed outside the outer sedimentation portion 22. A screw groove 12a formed in the cap 12 for mounting the breast feeding nipple 11 and a screw groove 15 of the neck portion 14 are formed so that the nipple 11 is mounted on the bottle body 16 by screwing. .

The thickness T ₁ of the neck 14 in the baby bottle of the present invention is usually 3.0 to 3.8 mm, preferably 3.5 to 3.7 mm. Further, the thickness T ₂ of the body portion 18 is generally 0.4mm or more, preferably 0.5 to 1.0 mm. Further, the thickness T ₃ of the lower shoulder 19 is usually 0.4.
mm or more, preferably 0.5 mm or more, more preferably 0.75 mm or more. The bottom wall thickness T ₄ is usually 2.0 mm or more, preferably 2.2 to 2.5 mm.

The baby bottle shown in FIG. 2 has a curved cylindrical shape in which the body portion 31 of the bottle main body 30 is smoothly depressed so that a user's hand such as a mother feeding a baby can easily grip the handle. This is an example.

In the baby bottle of the present invention, the bottle body 16 and the bottle body 30 are made of polyphenylsulfone resin.
The injection blow molded bottle of the present invention has a generally bottomed cylindrical shape as described above, but the molded bottle of the present invention improves the yield due to the use of polyphenylsulfone resin. Therefore, the bottom is formed in a predetermined shape.

  The polyphenylsulfone resin used as a molding material in the molding bottle of the present invention has a repeating unit represented by the following formula.

  Typical physical properties of this polyphenylsulfone resin are: specific gravity (according to ASTM D792) is 1.3, tensile strength (according to ASTM D638) is 70 MPa, melt flow (according to ASTM D1238, under 380 ° C., 0.3 MPa) 15-30, preferably 17-25 g / 10 min. The glass transition temperature is 220 ° C. (according to ASTM D3418), and the resin temperature is usually 300 to 390 ° C., preferably 340 to 380 ° C. Polyphenylsulfone resin has extremely high heat resistance and excellent chemical resistance, so it can be boiled or sterilized by steam or microwave using a microwave oven, or disinfecting and sterilizing with chemicals such as sodium hypochlorite aqueous solution. In this case, deformation and erosion of the molded bottle can be prevented, and the impact resistance is excellent, and excellent toughness is exhibited even in a harsh environment.

It does not specifically limit as said polyphenyl sulfone resin, For example, RADEL R-5
000, RADEL R-5800 (manufactured by Solvay Advanced Polymers Co., Ltd.) and the like are commercially available and can be suitably used. In addition, the molded bottle of the present invention may be blended with other various additive materials such as an elastic member and a filler within the range that does not impair the object of the present invention, using the polyphenylsulfone resin as a main raw material. .

  There are very few resins that can be molded while having such physical properties, and there is a polyether sulfone resin (PES) as a resin having relatively close characteristics. A baby bottle using this resin has already been filed and patented. (See Japanese Patent No. 3506646).

  Since baby bottles made of polyethersulfone resin do not elute bisphenol, which is an environmental hormone, compared to polycarbonate and the like, they can be used with peace of mind for users such as infants and children. However, since the polyethersulfone resin itself is relatively hard, the baby bottle made of this polyethersulfone resin (PES) has a high probability of being damaged when dropped, and is molded using a resin with higher impact strength. A bottle is sought.

As a result of examining such resin for molded bottles, it was found that a polyphenylsulfone resin, which has higher impact strength than polyethersulfone resin (PES) and is not easily damaged by dropping, is suitable. That is, the polyphenylsulfone resin essentially exhibits higher impact resistance than the polyethersulfone resin (PES). However, since this polyphenylsulfone resin is harder to melt than a polyethersulfone resin, it is necessary to increase the heating temperature during molding as compared with the case of using a polyethersulfone resin (PES), and the difference is 10 It becomes close to ℃. Since the heating temperature at the time of molding in the case of using a polyethersulfone resin has already exceeded 300 ° C., in order to perform molding at a temperature even higher by about 10 ° C., a polyethersulfone resin ( There is a need to further improve the high temperature resin molding conditions employed in high melting point resins including PES).

For example, the molding bottle of the present invention can be manufactured by uniaxial stretching injection blow molding.
The parison used in the uniaxially stretched injection blow molding is formed from the polyphenylsulfone resin, and the length of the parison is approximately the length (depth) of the injection blow molded product to be obtained. Have the same length. Therefore, even if this parison is blow-molded, the resin hardly stretches in the longitudinal direction, and the parison expands in the circumferential direction and comes into contact with the inner peripheral wall surface of the mold to form the inner peripheral wall surface of the mold. A forming bottle is formed. Therefore, the molded bottle of the present invention is hardly stretched in the depth direction of the bottle.

  The molding bottle of the present invention is formed by an injection blow molding method using polyphenylsulfone resin. The parison used for blow molding the molding bottle is a gate for manufacturing the parison. The gate remains at the location (usually at the bottom of the parison). This gate trace is a projection of less than 1 mm that protrudes from the bottom of the parison, and if this projection is cut out and blow molded, welds caused by these projections are unlikely to occur and the starting point of the crack in the molding bottle is eliminated. It is possible. However, when the molding bottle of the present invention is manufactured by the injection blow molding method, since the melting point of the polyphenylsulfone resin is high, the use of cold parison reduces the yield, so use hot parison. However, when such a hot parison is used, it is very difficult to completely cut out the protrusion that is the gate trace.

  When using a hot parison, the molten resin is introduced from the gate toward the resin mold to form a predetermined parison mold, and then cooled to a temperature that can hold the mold body. A parison is inserted, air is fed while heating, and a resin forming the parison is expanded and pressed against the inner wall surface of the mold by this air pressure to form a molding bottle having a desired shape.

  In injection blow molding using a resin having a melting point lower than that of polyphenyl ether, such as production of a molding bottle using polyether sulfone resin (PES), the resin has a melt viscosity suitable for injection blow molding. Even if heated in this way, thermal deterioration of the resin due to heating hardly occurs, and injection blow molding can be performed at a relatively high speed. However, the polyphenylsulfone resin used in the present invention is suitable for injection blow molding unless the resin is heated to a temperature about 10 ° C. higher than the polyether sulfone resin, which is considered to be relatively difficult to blow. The melt viscosity cannot be increased. For this reason, even if the molding conditions employed in the polyethersulfone resin (PES) are applied as they are, it is difficult to stably produce a molding bottle made of a polyphenylsulfone resin.

  In the present invention, in order to blow-mold a molded bottle using a polyphenylsulfone resin, as shown in FIG. 6, it is not stretched in the depth direction of the bottle body but stretched in the circumferential direction, and is an injection blow of the uniaxial stretching method. A forming bottle is formed by molding. In addition, at this time, since the melting temperature of the polyphenylsulfone resin is high and there is no significant difference from the decomposition point, depending on the shape of the bottle main body 16 depending on the part by giving a difference in thickness in the thickness direction of the parison Heat to a temperature that makes it easy to deform. Furthermore, since the melt viscosity is low, when air is introduced rapidly, uneven thickness may occur and further damage may occur. Therefore, air is introduced at a high pressure adjusted so as not to cause significant uneven thickness. Give shape.

  By adjusting the blow pressure in this way, it is possible to obtain a molded bottle with a stable shape with little uneven thickness, but on the inner peripheral wall surface of the bottom of the molded bottle, probably due to the resin self-leveling property, Concavities and convexities are not formed on the inner peripheral wall surface of the bottom of the molding bottle, and a smooth spherical shape is obtained. That is, on the bottom outer surface wall of the bottle body of the present invention, there is a concentric central settling portion (concave portion) from the center surface of the spherical concave portion forming the bottom portion of the bottle body to the upper portion from the gate mark portion. Formed on the outer surface of the bottle body, and has a concavity and convexity that a concentric outer sedimentation portion (concave portion) is formed via an outer ring formed concentrically on the outer side. The unevenness formed on the bottom surface of the body is not formed.

Next, the shape of the bottom of the molding bottle of the present invention will be described in detail with reference to the drawings.
About the outline of the shape in the bottom part of the shaping | molding bottle of this invention, it is as having shown in the longitudinal cross-sectional view of FIG. 1 (A), and the bottom back view of FIG. 1 (B). As described above, the bottom portion of the molding bottle of the present invention has the bottom outer surface wall forming the concave portion 20 that is gently raised from the outer peripheral side toward the bottom center, and the concave portion 20 from the center surface to the top. A concentric central sedimentation portion 21 is formed toward the center, and an annular outer sedimentation portion 22 is formed outside the central sedimentation portion 21 via a concentric outer ring portion. A convex inner outer ring portion 24 is formed outside the central sedimentation portion 21 and inside the outer sedimentation portion 22, and a convex outer outer ring portion 25 is formed outside the outer sedimentation portion 22. On the other hand, the inner wall of the bottom of the forming bottle forms a smooth spherical surface 23 with no irregularities.

  The reason why the plurality of settling portions 21 and 22 and the convex outer ring portions 24 and 25 are formed at the bottom of the molding bottle is that the trace of the gate generated when the parison is injection molded causes cracking or breakage of the molding bottle. This is to obtain a molded bottle with higher impact resistance. This crack is caused by using a polyphenylsulfone resin that originates from fine welds or scratches that occur outside the gate trace when the bottom is molded so that it is pushed in while leaving the gate trace. In the case of a bottle made of polyphenylsulfone resin, the crack generated in this way further grows and the bottle itself is broken. Such bottle breakage is a condition often seen in polyphenylsulfone bottles, which is a factor that lowers the impact resistance of bottles made using polyphenylsulfone resin, which is inherently high in impact resistance. It has become.

  That is, as shown in the longitudinal sectional view of the bottom of the parison shown in FIG. 3, when the parison is injected, fine projections, so-called gate traces 41, are formed on the normal gate portion. When the gate finishes the injection and is stored in the injection cylinder, the molten resin is drawn from the parison to the gate side as the gate moves, and this is caused as a trace. There is a molding machine equipped with such a function of trimming the gate mark 41. However, when injection blow molding is performed using a hot parison, the temperature of the hot parison is as high as possible in order to prevent deterioration of the resin due to reheating. Since it is necessary to maintain the temperature and the shape of the hot parison is not stable, it is difficult to completely remove the gate trace, and the parison with the gate trace left is moved to the mold as it is and blow-molded.

  When a parison having such a gate trace 41 is blow-molded, the gate trace 41 receives a force a that is pushed into the cavity from the mold wall surface indicated by an arrow as the parison expands, and the gate trace having a thinner resin than the gate trace 41 is formed. The side periphery 42 is crushed together with the gate trace 41.

FIG. 4 is a vertical cross-sectional view of the bottom portion of the forming bottle after blow molding in the case where the bottom surface is formed without providing a sink portion or the like. Since the gate mark 41 is crushed when blown, a fine weld 43 tends to be formed from the outer surface of the molding bottle to the inside after the molding in the peripheral part 42 of the gate mark, and this weld 43 causes the molding indicated by the arrow. It is considered that the strength at the bottom of the bottle is reduced with respect to the stress b from the inside of the molded bottle. The stress b from the inside of the forming bottle toward the bottom of the forming bottle is a small weld in the peripheral edge portion 42 of the gate trace, particularly when the whole forming bottle is dropped with the liquid filled as the contents of the forming bottle. Cracks starting from 43 are likely to occur. That is, in the bottle body using polyphenylsulfone resin, cracks are likely to occur from the fine weld 43 formed on the gate trace side peripheral portion 42 as described above due to the drop impact, and the bottle body itself is damaged from the cracks. This causes damage inherent to polyphenylsulfone bottles.

  According to the present invention, by giving a specific shape to the bottom of the molded bottle, cracks and the like at the bottom of the molded bottle starting from the weld generated around the gate trace are prevented, and the polyphenylsulfone bottle Drop impact resistance is improved.

The shape at the bottom of the molding bottle of the present invention will be described more specifically. (C) and (D) shown in FIG. 5 are both partially enlarged views of the longitudinal sectional view 1 (A) of the molded bottle of the present invention.
As shown in FIG. 5 (C), the bottom outer surface wall of the bottle of the present invention forms a concave portion 50 that is raised in a smooth spherical shape from the outer peripheral side of the molded bottle toward the center of the bottom. By making the outer surface wall at the bottom part a gentle spherical surface instead of a flat surface, it is estimated that the recess 50 absorbs and relaxes the impact received during the fall, and higher impact resistance can be imparted. . Note that the concave portion raised to a spherical shape on the outer wall of the lower portion is raised to a curved surface even if the substantially central region where the bottom is raised is slightly flat as shown in FIG. Also included are those that are curvedly connected to the outer periphery. In general, when producing a bottle by injection blow molding, if the bottom shape retention force is low and the demolding timing is early, the bottom does not become a flat spherical shape as shown in FIG. A so-called “shrinkage” occurs in which the central portion falls downward. However, when such a “shrinkage” occurs, cracks from the fine weld 43 are likely to occur.

  In the bottle of the present invention, a concentric central settling portion 21 is formed on the surface of the central portion of the recess 50 that forms the bottom of the bottle. The center of the portion corresponds to the portion where the gate trace 41 is located.

Furthermore, an annular outer settling portion 22 is formed outside the central settling portion 21 via a concentric convex inner outer ring portion 24.
That is, in the bottom of the molding bottle of the present invention, the central sedimentation portion 21 and the outer sedimentation portion 22 form a convex portion 54 that is a convex inner outer ring portion 24 between them, and the gate 41 that originally tends to generate the weld 43 is formed. An annular convex portion 54 is formed at a position corresponding to the gate trace side peripheral portion 42 serving as the outer periphery. Since the convex portion 54 has an increased resin thickness compared to the resin thickness of the other bottom portion, the formation of the annular convex portion 54 increases the strength of the bottom portion of the bottle and The form retainability becomes high, and “bottoming” at the bottom is less likely to occur. Further, when the parison is pressed against the mold and deformed, the molten resin that contacts the central sedimentation portion 21 and the external sedimentation portion 22 is pushed out to the periphery thereof, so that the convex portions are projected from the central sedimentation portion 21 and the external sedimentation portion 22. Stress c indicated by a plurality of arrows acts toward 54 and presses the resin in the direction of the weld generation position, so that the weld 43 is less likely to be generated in the gate trace side peripheral portion 42. Therefore, it is possible to suppress the occurrence of the fine weld 43 in the gate trace side peripheral portion 42, which is considered to be a cause of cracks at the bottom, and to obtain a molded bottle having a higher drop impact property.

In this way, as shown in the bottom rear view of FIG. 1B, a convex inner outer ring portion 24 that is a convex portion 54 outside the central sedimentation portion 21, an annular outer sedimentation portion 22 outside, and an outer side thereof. Further, a convex outer outer ring portion 25 that further has a convex portion is formed. That is, the gate 41 is positioned at the center settling portion 21 and the gate trace peripheral portion 42 is positioned at the convex inner outer ring portion 24. By giving such a shape to the bottom portion, the stress c directed to the convex portion 54 can be effectively applied, and the weld 43 can hardly be generated by the gate trace side peripheral portion 42. That is, by forming the central sedimentation portion 21 and the outer sedimentation portion 22 at the bottom of the forming bottle, it is possible to suppress the generation of welds due to the gate marks and to effectively prevent cracks and the like starting from the welds. In addition, since the convex inner outer ring portion 24 and the convex outer outer ring portion 25 project in an annular shape, it also functions as a reinforcing portion, and it is possible to prevent cracking of the bottom surface portion together with the settling portions 21 and 22.

In FIG. 5 (D), in the concave portion 50 at the bottom of the bottle body, a vertical cross-section curve when assuming a state in which a smooth curved surface remains without forming the central sedimentation portion 21 and the outer sedimentation portion 22, that is, A virtual bottom curve _50a is shown. The height h ₂ is calculated from the virtual bottom curve 50 _a to the central settling part 2
The distance 1 to the most depressed position and the height h ₃ indicate the distance from the virtual bottom curve 50 _a to the most depressed position of the outer sedimentation part 22.

In FIG. 5, h ₂ is set to 0.3 mm, h ₃ is set to 0.41 mm, and the bottom wall thickness T ₄ is 2.4 m.
An example of a baby bottle is shown in which the distance 58 from the center of the central settling portion 21 to the center of the outer settling portion 22 is set to 3.6 mm. In this baby bottle, the distance 59 from the center of the central sedimentation portion 21 to the contact point between the outer sedimentation portion 21 and the virtual bottom curve 50 _a is 1.8 mm.
It is. The ratio of h ₂ to h ₃ is h ₂ / h ₃ = 0.7317. That is, in the baby bottle of the present invention, by setting the ratio of h ₂ and h ₃ to the above values, the depression formed by the outer sedimentation section 22 is more than the depression formed by the central sedimentation section 21. It becomes deeper, and it becomes possible to more effectively suppress the generation of the weld 43 in the gate trace side peripheral portion 42.

Structure of the bottom surface of the molded bottle of the present invention as described above, the height h ₂ is generally from 0.38 to 0.43
mm, preferably 0.39 to 0.42 mm, and the height h ₃ is usually 0.28 to 0.33 mm,
Preferably, it can be varied by 0.29 to 0.31 mm. The distance 58 is usually in the range of 3.4 to 3.8 mm, preferably 3.55 to 3.65 mm, and the distance 59 is usually 1.7 to 1.9 mm, preferably 1.75. Within the range of ˜1.85 mm, and the ratio of h ₂ to h ₃ is usually 0.68 <h ₂ / h ₃ <0.78, preferably 0.70 <h ₂ / h ₃ <0. It can be varied within a range of .75. Further, at this time, the convex inner outer ring portion 24 and a convex outer outer ring portion 25 is configured to slightly protrude from the lower bottom curve 50 _a,
The amount of protrusion is smaller than the amount of depression in the center settling portion 21 and the outside settling portion 22.

In FIG. 1, the height (h ₁ ) at the highest position of the bottom of the molded bottle is set to 4.7 to 4.8 mm in the case of the baby bottle of the present invention. Thus, when the height (h ₁ ) at the highest position of the bottom of the forming bottle is set as described above, a spherical surface that can be smoothly curved can be provided on the outer wall of the bottom of the forming bottle, thereby forming a flat surface. It is possible to absorb and relieve stress in the case of dropping than a molded bottle having a bottom portion, and the impact resistance of the bottom portion is further improved. In the present invention, the height (h ₁ ) at the highest position of the molded bottle bottom is usually 4.3 to 5.2 mm, and preferably can be varied in the range of 4.6 to 5.0 mm.

  As described above, since the molding bottle of the present invention is blown and then slowly cooled and then demolded, even in the case of polyphenylsulfone resin, sufficient self-form retention is exhibited during that time, and after demolding Thus, there is no so-called “shrinkage” of the bottom part, in which the center part of the bottom outer surface wall of the molding bottle falls downward, and a molded bottle having a bottom outer wall having a gentle spherical shape can be obtained.

The bottom outer surface wall of the molded bottle of the present invention is formed in an uneven shape as described above, but the unevenness formed in the bottom outer peripheral wall surface is not reflected on the bottom inner peripheral wall surface, and there is no unevenness. A smooth spherical surface 56 is formed. By making the bottom inner peripheral wall surface a spherical surface 56 with no irregularities,
It is possible to suppress the occurrence of uneven thickness in the resin thickness in the vicinity of the outer periphery of the bottom portion, and to maximize the effect of the uneven shape of the bottom outer surface wall formed to suppress the weld generation in the peripheral portion 42 of the gate trace side. it can. In addition, the smooth spherical surface having no irregularities on the inner wall surface of the bottom portion includes the presence of a protruding portion or the like that slightly protrudes during molding. Moreover, since there is no unevenness | corrugation in the inner peripheral wall surface of a bottom part, even if the content with which a molding bottle is filled adheres, it is easy to wash | clean.

  Thus, in order to make the bottom inner peripheral wall surface into the spherical surface 56 without unevenness, for example, it can be formed by adjusting the pressure of the air introduced during blow molding. Furthermore, by adjusting the pressure of air at the time of blow molding or by deforming by applying pressure to the gate 41 in advance as will be described later, first, irregularities on the bottom outer surface wall are formed so as to erase the weld trace, Further, the resin is uniformly distributed over the entire inner wall of the bottom without reflecting unevenness formed on the outer peripheral wall surface of the bottom by being uniformly stretched over the entire bottom, and can be formed into a smooth spherical shape.

The molding bottle of the present invention can be produced by the injection blow molding method as described above.
FIG. 6 shows an example of an injection blow mold for producing the molding bottle of the present invention.

  The molding bottle of the present invention can be usually produced by a uniaxially stretched injection blow molding method using a hot parison. Either injection blow molding or biaxial stretching (extension blow molding) may be used, but biaxial stretching tends to cause uneven thickness in the resulting molded bottle, and therefore, uniaxial stretching is preferred in the present invention. In particular, polyphenylsulfone resin has a high melting point and a high melt viscosity, so that uneven thickness is likely to occur. However, a uniaxial stretching can provide a molded bottle having a more uniform thickness.

  When adopting a uniaxial stretching method as an injection blow molding method, first, a polyphenylsulfone resin pellet is kneaded and melted as a raw material, from a gate (not shown) arranged at a position corresponding to the center of the bottom of the parison. The molten resin is extruded and a cylindrical parison 60 is injection molded. Next, the parison 60 is moved to a blow molding machine 70 shown in FIG.

  The blow molding machine 70 includes a mold 72 that forms a blow cavity 71, and a rod portion 66 that includes a rod 75 and a blowing means for blowing air into the parison 60. The mold 72 has a parting line (divided surface) at the longitudinal center, and includes left and right molds 77 and 78 and a bottom mold 79.

  A receiving mold 64 corresponding to the lip mold 62 is provided at the upper part of the left and right molds 77, 78, and a receiving mold 68 fitted from the left and right side surfaces of the bottom mold 79 is provided at the lower part. The rod 75 is on the same axis as the bottom mold 79 and is disposed at the center of the left and right molds 77 and 78.

  The blowing means 76 has a columnar blow core 66 that is detachably fitted to the inner periphery of the lip mold 62. An air blowing hole is provided at the tip of the blow core 66, and high pressure air is blown into the bottomed parison 60 from an air pressure feeding device connected to the blow core 66.

  Note that the blow molding machine 70 may include a cooling means for cooling the baby bottle after blow molding, and the rod 75 is provided with a blow cavity so that, for example, the molded bottle body can be removed. An operating mechanism capable of reciprocating up and down in the axial direction of 71 may be provided.

The parison 60 is uniaxially stretched by the blow molding machine 70 as follows. First, the left and right molds 77, 78 and the bottom mold 79 are clamped to form the mold 72, and then the parison 60
The lip mold 62 holding the rim is fitted to the receiving mold 64, and the parison 60 is disposed in the blow cavity 71.

  At this time, the parison 60 is substantially the same as the length of the blow cavity 71 in the vertical direction. Similarly, the parison 32 in the baby bottle shown in FIG. 2 is formed to be substantially the same as the length of the blow cavity 71 in the vertical direction. That is, as shown in FIG. 6, the bottom surface of the parison 60 is configured to contact the top surface of the bottom mold 79, and at this time, the gate 41 located at the center of the bottom surface of the parison 60 is connected to the rod 75 and the bottom portion. The mold 79 is crushed by the top surface.

FIG. 7E is an enlarged view of the bottom mold 79, and FIG. 7F is a sectional view thereof.
As shown in FIG. 7 (E), the mold of the present invention is a bottom mold 79 capable of molding the molding bottle of the present invention, and increases the strength of the bottom of the bottomed substantially cylindrical molding bottle. Therefore, it has unevenness corresponding to the shape of the bottom of the forming bottle to be formed. That is, the outer surface wall of the bottom mold 79 forms a convex portion 80 that is raised in a gentle spherical shape from the outer peripheral side toward the center of the bottom portion, and is concentric from the center surface of the convex portion 80 toward the top. A central raised portion 82 is formed, and an annular outer raised portion 83 is formed outside the central raised portion 82 via a concentric outer ring portion. Then, a concave inner outer ring portion 87 that is concentrically settled from the surface of the central portion of the convex portion 80 toward the lower portion is formed outside the central raised portion 82, and the center of the convex portion 80 is formed outside the outer raised portion 83. A concave outer ring portion 88 that is concentrically settled from the surface of the portion toward the lower portion is formed.

FIG. 7 (F) shows a vertical cross section curve in a case where the convex portion 80 is assumed to be a smooth curved surface without forming the central raised portion 82 and the outer raised portion 83, that is, the virtual bottom curve. It shows the 80 _a. The height h ₄ indicates the distance from the virtual bottom curve 80 _a to the most raised position of the central raised portion 82, and the height h ₅ indicates the distance from the virtual bottom curve 80 _a to the highest raised position of the outer raised portion 83.

In FIG. 7 (F), h ₄ is set to 0.3 mm, h ₅ is set to 0.41 mm, and the distance 84 from the center of the central raised portion 82 to the center of the outer raised portion 83 is set to 3.6 mm. ing. Distance 86 from the center of the central elevated portion 82, to the contact point between the outer ridges 83 and the virtual base curve 80 _a is
It is set to 1.8 mm. Ratio of the h ₄ and h ₅ are set to h ₄ / h ₅ = 0.7317. In other words, in the baby bottle mold of the present invention, by setting the ratio of h ₄ and h ₅ to the above values, the protrusion formed by the outer raised portion 83 rather than the protrusion formed by the central raised portion 82. Thus, the generation of the weld 43 in the gate trace side peripheral portion 42 can be more effectively suppressed.

In the mold of the molding bottle of the present invention, the height h ₄ is usually 0.38 to 0.43 mm, preferably 0.39 to 0.42 mm, and the height h ₅ is usually 0.28 to 0.48 mm. 0.33 mm, preferably 0.29 to 0.31 mm, and the distance 84 is usually 3.4 to 3.8 mm, preferably 3.55 to 3.65 mm, and the distance 86 is Usually, it can be varied within a range of 1.7 to 1.9 mm, preferably 1.75 to 1.85 mm. Further, the height (h ₆ ) of the mold is usually varied within a range of 4.0 to 5.5 mm, preferably 4.5 to 5.0 mm, more preferably 4.7 to 4.8 mm. Is possible. Further, the value of the ratio between h ₄ and h ₅ is usually 0.68 <h ₄ / h ₅ <0.78, preferably 0.70 <h ₄ / h ₅ <0.75. be able to. Within this range, it is possible to give a substantially curved shape that curves smoothly at the bottom of the molded bottle, and it is possible to disperse the stress at the time of dropping rather than a molded bottle having a bottom that forms a flat surface. Therefore, the impact resistance at the bottom of the molded bottle is further improved. Further, the concave inner outer ring portion 87 and the concave outer outer ring portion 88 is configured recessed slightly from the virtual base curve 80 _a.

  The bottom mold of the present invention has the above-described configuration, but the shape of the mold of the body part is not particularly limited, so the parting line (divided surface) of the mold is arbitrarily set depending on the shape of the body part and the like. it can. The mold shown in FIGS. 6 and 7 is an embodiment in which parting lines are provided on the bottom and the body.

Moreover, if the metal mold | die of this invention is used, the molding bottle which raised the intensity | strength of the bottom part can be shape | molded, without being limited to the molding material of the molded product obtained. Furthermore, the material of the mold is not limited.
After the left and right molds 77 and 78 and the bottom mold 79 are installed, high-pressure air is blown into the parison 60 from the blow hole of the blow core 66 to extend the parison, and the left and right molds 77 and 78 and the bottom mold 79 are formed. Form in desired shape. When air with adjusted pressure is blown, the polyphenylsulfone resin can be properly stretched, and uneven feeding can be suppressed to obtain a baby bottle with a uniform wall thickness. Further, as described above, a molded bottle having a bottom inner wall that has a smooth spherical shape can be obtained.

  After cooling, the molded product is taken out from the mold. This cooling is also performed at a low speed. By slowly cooling, the polyphenylsulfone resin can sufficiently exhibit self-form retention, and after taking out the molding bottle from the mold, it suppresses the occurrence of “shrinkage” at the bottom, It is possible to obtain a molded bottle having a concave shape whose outer wall is raised to a gentle spherical shape.

As a result of a drop strength test on the molded bottle of the present invention, it was found that the bottle has a very high drop height.
This drop strength test was performed using a baby bottle with a dose of 240 ml having the shape shown in FIG. This baby bottle is made of polyphenylsulfone resin (trade name: RADEL R-5000,
And manufactured by injection blow molding as described above using Solvay Advanced Polymers).

That is, the thickness of the baby bottle is T ₁ = 3.6 mm, T ₂ = 0.6 mm, T ₃ = 0.8 mm
T ₄ = 2.4 mm, the height of the bottom of the baby bottle is h ₁ = 4.8 mm. The value of h ₂ in the recess (B) at the bottom was 0.3 mm, the value of h ₃ was 0.41 mm, and the distance 58 was 3.6 mm. The bottom mold of the blow mold used to manufacture such a baby bottle has an h ₄ value of 0.3 mm, an h ₅ value of 0.41 mm, and a distance 84 of 3.6 mm. .

  Twenty baby bottles manufactured in this manner were filled with water at room temperature up to the maximum indicated dose of 240 ml, and a baby bottle nipple, cap and hood were attached to the baby bottle, and a drop test was conducted. A vinyl tile with a thickness of 2.8 mm stretched on the concrete floor is placed at the drop point, and the surface hardness measured with a Type A hardness meter specified in ASTM D2240 is about 90 degrees Shore A at maximum. there were.

  The 20 baby bottles were dropped from the height of 1.37 m onto the vinyl tile 10 times from the bottle bottom direction, and the damage state was investigated from the appearance. As a result, there was no abnormality such as cracking or breakage for all baby bottles. For comparison, a drop test was performed on baby bottles that did not form irregularities on the bottom. The baby bottle broke along the cracks that occurred from the trace. Further examination of baby bottles that did not break revealed that cracks occurred from the gate trace near the center of the bottom.

  Thus, the molded bottle of the present invention has a very high strength by making the shape of its bottom part a predetermined shape, and has a very high strength and is not easily damaged by dropping.

  The molded bottle of the present invention is preferably used as a baby bottle used by infants, which has a high fall frequency. However, the molded bottle of the present invention is not limited to a baby bottle, and can be used as a bottle for filling various liquids such as soft drinks, drinks, carbon dioxide-containing beverages, beer, and alcoholic beverages.

The molded bottle of the present invention is formed from a polyphenylsulfone resin having higher impact characteristics than polyethersulfone resin (PES) as resin characteristics. Polyphenylsulfone is a high-strength resin, but it has a problem inherent to a polyphenylsulfone resin-molded bottle in that cracks are likely to occur from the bottom due to moldability. According to the present invention, by forming the shape of the bottom of the polyphenylsulfone molding bottle into a specific shape, it is possible to prevent the occurrence of cracks from the peripheral edge of the gate trace. Therefore, according to the present invention, a highly practical molded bottle using polyphenylsulfone is provided. Molded bottles formed from such polyphenylsulfone are not only high in strength, but also have no bisphenol skeleton, so environmental hormones are not generated and have very high safety.

It is a longitudinal cross-sectional view of the feeding bottle which is one aspect | mode of the bottomed substantially cylindrical injection blow molding bottle of this invention. It is a longitudinal cross-sectional view of the feeding bottle which is one aspect | mode of the bottomed substantially cylindrical injection blow molding bottle of this invention. It is a bottom longitudinal section of a parison. It is a longitudinal cross-sectional view of a molding bottle bottom part after blow-molding a parison. It is a center part longitudinal cross-sectional enlarged view of the bottomed substantially cylindrical injection blow molding bottle of this invention. It is a longitudinal cross-sectional view which shows the state by which a bottomed parison is inserted in a blow molding machine and blow-molded to a molded object. It is the enlarged view and longitudinal cross-sectional view of the bottom part metal mold | die of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Protective cap 11 Feeding nipple 12 Cap 12 _a Screw groove 13 Opening part 14 Neck part 15 Screw groove 16 Bottle main body 17 Upper shoulder 18 Body part 19 Lower shoulder 20 Bottom part 21 Central sedimentation part 22 Outer sedimentation part 23 Spherical surface 24 Convex inner outer ring Part 25 Convex outer outer ring part 30 Bottle body 31 Body part 32 Parison 41 Gate trace 42 Gate trace side peripheral part 43 Weld 50 Recess 50 _a Virtual bottom curve 54 Convex part 56 Spherical surface 58 From the center of the central sedimentation part 21 to the outer sedimentation part 22 receiving mold 66 blow core 68 receiving mold 70 blow molding machine 71 blow cavity 72 gold distance 59 center precipitation unit 21 to the center corresponding to the distance 60 parison 62 lipped 64 lip mold 62 to contact with the virtual bottom curve 50 _a of Mold 75 Rod 76 Blowing means 77 Left mold 78 Right mold 79 Bottom mold 80 Convex 80 _a Contact from the center of the virtual bottom distance from the center of the curve 82 the central elevated portion 83 outer ridge 84 central raised portion 82 to the center of the outer ridges 83 86 central elevated portion 82, an outer ridge 83 and the virtual base curve 80 _a Distance to 87 Concave inner outer ring part 88 Concave outer outer ring part

Claims (7)

A bottomed substantially cylindrical injection blow molded bottle, the molded bottle comprising a polyphenylsulfone resin having a repeating unit represented by the following formula (1):
The bottom outer wall of the molding bottle forms a concave portion that is raised to a gentle spherical shape from the outer peripheral side toward the center of the bottom, and
A concentric central sedimentation part is formed from the surface of the central part of the spherical concave part toward the upper part,
Furthermore, on the outside of the concentric central settling part, an annular outer settling part is formed via a concentric convex inner outer ring part,
An injection blow molded bottle characterized in that the inner wall of the bottom of the molded bottle forms a smooth spherical surface without irregularities;

The convex inner outer ring portion projects concentrically from the center surface of the spherical concave portion toward the lower portion,
2. The injection blower according to claim 1, wherein a convex outer outer ring portion that is concentrically protruding from a central surface of the spherical concave portion toward a lower portion is formed outside the outer settling portion. Molded bottle. In the case where a hypothetical bottom curve that is a smooth spherical shape is assumed without forming the central sedimentation portion and the outer sedimentation portion in the recess,
The most depressed position in the concentric central settling portion formed from the center surface of the spherical concave portion of the bottom outer surface wall of the molding bottle toward the top is 0.38 to 0.43 mm in height from the virtual bottom curve. The position of
In addition, the most depressed position in the annular outer settling portion formed through the concentric outer ring portion on the outer side of the concentric central settling portion is a position 0.28 to 0.33 mm in height from the virtual bottom curve. The injection blow-molded bottle according to claim 1 or 2, wherein   The injection blow-molded bottle according to any one of claims 1 to 3, wherein the molded bottle is a baby bottle. A mold used for forming a bottomed substantially cylindrical molding bottle,
The bottom outer surface wall of the mold forms a convex portion raised to a gentle spherical shape from the outer peripheral side toward the bottom center,
A concentric central protuberance is formed from the center surface of the spherical convex portion toward the top,
Further, the bottom portion of the bottomed substantially cylindrical shaped bottle is formed, wherein an annular outer raised portion is formed on the outer side of the concentric central raised portion via a concentric concave inner outer ring portion. Mold used for. The concave inner outer ring portion is concentrically settled from the center surface of the spherical convex portion toward the lower portion,
6. The gold outer ring according to claim 5, further comprising a concave outer outer ring portion that is concentrically settled from a surface of a central portion of the spherical convex portion toward a lower portion outside the outer protruding portion. Type. In the case where a hypothetical bottom curve that is a smooth spherical shape is assumed without forming the central raised portion and the outer raised portion on the convex portion,
The most raised position of the concentric central bulge formed from the center surface of the spherical convex portion of the bottom outer surface wall of the mold toward the top is 0.38-0. 43mm position,
In addition, the most prominent position of the annular outer bulge formed on the outer side of the concentric central bulge via the concentric outer ring portion is a position having a height of 0.28 to 0.33 mm from the virtual bottom curve. The mold according to claim 5 or 6, which is used to mold the bottom of the bottomed substantially cylindrical shaped bottle according to claim 4.

Images