CN111531847A

CN111531847A - Special-shaped section bottle blank structure and forming method thereof

Info

Publication number: CN111531847A
Application number: CN202010518427.6A
Authority: CN
Inventors: 谢国基; 姜晓平; 胡青春; 罗国泉; 陈境钰; 卢佳
Original assignee: GDXL Precise Machinery Co Ltd
Current assignee: GDXL Precise Machinery Co Ltd
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2020-08-14

Abstract

The invention discloses a special-shaped section bottle blank structure and a forming method thereof, wherein a blank body of the special-shaped section bottle blank structure comprises an annular section, a section changing section and a special-shaped section, the special-shaped section has a special-shaped section, the shortest distance between an inner closing line and an outer closing line of the special-shaped section is the wall thickness of the bottle blank structure, the outer closing line is a fold line shape, and compared with the annular section bottle blank structure with the same length and the same gram weight of the special-shaped section bottle blank structure, the annular section bottle blank structure is provided with an annular section, the circumference of the special-shaped section is larger than the circumference of the annular section on the premise that the bottle blowing stretch ratio of the special-shaped section bottle blank structure is equal to the bottle blowing stretch ratio of the annular section bottle blank structure, and the wall thickness of the special-shaped section bottle blank structure. The special-shaped cross-section bottle blank structure can effectively shorten the cooling time of the injection molding of the bottle blank and the preheating time before bottle blowing, thereby shortening the whole processing period of the bottle and improving the production efficiency.

Description

Special-shaped section bottle blank structure and forming method thereof

Technical Field

The invention relates to the technical field of bottle blanks, in particular to a bottle blank structure with a special-shaped cross section and a forming method thereof.

Background

Due to the characteristics of high efficiency and manufacturability of injection molding, injection molding has become the most common method for manufacturing plastic products, and has a very important position in the plastic processing industry. The cooling is the most important stage in the injection molding process, and has a great influence on the quality and the production efficiency of the product, the cooling time occupies about 2/3 of the whole injection molding time, and the cooling time is a key influence on the product forming period and the energy consumption. At present, the research on the cooling technology for accelerating the formed part at home and abroad mainly focuses on accelerating the heat dissipation part of the mold, however, because the heat conductivity coefficient of the bottle blank material is extremely small, the self heat resistance is far greater than the heat resistance of a cooling system and the mold in the cooling process, the self heat resistance of the bottle blank is the main factor influencing the cooling efficiency, and the reduction of the cooling time is substantially limited by improving the heat exchange coefficient of cooling water and the heat conductivity coefficient of the mold material in the prior art.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a bottle blank structure with a special-shaped cross section and a forming method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a bottle blank structure with a special-shaped section comprises a bottle mouth, a blank body and a blank bottom, wherein the blank body comprises an annular section, a section changing section and a special-shaped section, the annular section is connected with the bottle mouth, the special-shaped section is connected with the blank bottom, the section changing section is a transition section between the annular section and the special-shaped section,

the special-shaped section is provided with a special-shaped section, the special-shaped section is composed of an inner closing line and an outer closing line, the shortest distance between the inner closing line and the outer closing line is the wall thickness of the bottle blank structure, the outer closing line is in a fold line shape and comprises a plurality of wave crests and wave troughs,

compared with the annular-section bottle blank structure with the same length and the same gram weight of the special-shaped-section bottle blank structure, the annular-section bottle blank structure is provided with the annular section, the circumference of the special-shaped section is larger than that of the annular section on the premise that the bottle blowing stretching ratio of the special-shaped-section bottle blank structure is equal to the bottle blowing stretching ratio of the annular-section bottle blank structure, and the wall thickness of the special-shaped-section bottle blank structure is smaller than that of the annular-section bottle blank structure.

The invention also provides a forming method of the bottle blank structure with the special-shaped section, which comprises the following steps:

s1 provides a conventional bottle blank structure, which comprises a bottle mouth, a blank body and a blank bottom, wherein the blank body is hollow and cylindrical and has a circular cross section consisting of an outer closed line and an inner closed line, the outer diameter and the inner diameter of the circular cross section are m and n respectively, and the area of the circular cross section is S_{Ring (C)}；

S2, changing at least the shape of the outer closed line of the circular ring-shaped section into a fold line shape, wherein the fold line shape is provided with a plurality of wave crests and wave troughs so as to form a special-shaped section,

specifically, the number of wave crests is preset, an included angle theta between the wave crests and a connecting line of wave troughs and the center of the circular ring shape is obtained, and a special-shaped section model is established on the premise that the area of the special-shaped section is not changed relative to the area of the circular ring-shaped section;

s3, obtaining a bottle blank structure with a special-shaped section according to the special-shaped section model, wherein the gram weight and the bottle blowing stretch ratio of the bottle blank structure with the special-shaped section are equal to those of the conventional bottle blank structure, but the section perimeter of the bottle blank structure with the special-shaped section is larger than that of the conventional bottle blank structure, and the wall thickness of the bottle blank structure with the special-shaped section is smaller than that of the conventional bottle blank structure.

The invention improves the conventional bottle blank structure with the annular cross section in the prior art, keeps the length and the gram weight of the bottle blank unchanged while improving, changes the bottle blank structure with the annular cross section into the bottle blank structure with the special-shaped cross section, and compared with the annular cross section of the bottle blank structure with the annular cross section, the special-shaped cross section of the bottle blank structure with the special-shaped cross section has the same cross section area, increased cross section circumference and reduced bottle blank wall thickness, and the characteristics of the invention ensure that the bottle blank structure with the special-shaped cross section has the following beneficial effects:

(1) because the circumference of the section is increased, the contact area of the bottle blank and the blowing mold is increased, thereby shortening the cooling time of injection molding of the bottle blank, shortening the whole injection molding period and improving the production efficiency of the bottle blank;

(2) the wall thickness of the bottle blank is reduced, so that the heat conductivity of the bottle blank is better, the bottle blank is more uniformly preheated before blow molding, and the heating time is shortened, so that the energy consumption in the preheating process is reduced;

(3) the invention changes the bottle blank structure with the annular section into the bottle blank structure with the special-shaped section, but the stretch ratio of the bottle blank is kept unchanged, so the blow molding performance of the bottle blank is not changed, and the quality of a bottle formed by blow molding is not influenced.

Drawings

The present invention will be further described and illustrated with reference to the following drawings.

Fig. 1a is a schematic representation of a prior art bottle preform.

FIG. 1b is a cross-sectional view A-A of FIG. 1 a.

Fig. 2 is a schematic diagram of the structure of the bottle preform with the irregular cross section of the invention.

FIG. 3a is a sectional view of a deformed cross-sectional segment of the deformed cross-sectional bottle preform structure of example 1.

Fig. 3b is a schematic diagram of the modeling of the profiled cross-section of fig. 3 a.

FIG. 4a is a sectional view of a deformed cross-sectional portion of the deformed cross-sectional preform structure in example 2.

Fig. 4b is a schematic diagram of the modeling of the profiled cross-section of fig. 4 a.

FIG. 5a is a sectional view of a shaped section segment of the shaped section preform structure in example 3.

Fig. 5b is a schematic diagram of the modeling of the profiled cross-section of fig. 5 a.

Fig. 5c is a partial enlarged view of fig. 5 b.

FIG. 6a is a sectional view of a shaped section segment of the shaped section preform structure in example 4.

Fig. 6b is a schematic modeling diagram of the profiled cross-section of fig. 6 a.

Fig. 7 is a graph of cooling temperature data for prior art preforms and preforms of the present invention during injection molding testing.

Fig. 8 is an infrared cloud of cooling temperatures of prior art bottle preforms and bottle preforms of the present invention during injection molding testing.

Fig. 9 is an infrared cloud of the heating temperature of prior art preforms and preforms of the present invention in a blow molding test.

Detailed Description

The technical solution of the present invention will be more clearly and completely explained by the description of the preferred embodiments of the present invention with reference to the accompanying drawings.

The prior art shown in fig. 1a and 1b is a conventional preform structure, and the conventional preform structure 10 ' includes a bottle opening 1 ', a body 2 ', and a base 3 ', and the body 2 ' is located between the bottle opening 1 ' and the base 3 '. As shown in fig. 1b, when the blank 2 ' has a circular cross section, the outer diameter of the circular cross section is m, the inner diameter of the circular cross section is n, the thickness t ' of the blank 2 ' is m-n, and the area of the circular cross section is:

in order to shorten the cooling time of plastic bottle injection molding, the invention researches and designs the shape of a bottle blank structure.

As shown in fig. 2, the bottle preform structure 20 with a special-shaped cross section of the present invention includes a bottle mouth 1, a preform body 2, and a preform bottom 3, wherein the preform body 2 is located between the bottle mouth 1 and the preform bottom 3. Specifically, the blank body 2 includes a ring-shaped section 21, a section changing section 22, and a deformed section 23. Wherein, the ring-shaped section 23 is connected with the bottle mouth 1 and has a ring-shaped section shape; the shaped section segment 23 is connected to the blank bottom 3 and has a shaped cross-sectional shape, where "shaped" is a cross-sectional shape different from the circular cross-sectional shape with respect to the circular shape; the cross-sectional variation 22 is a transition between the annular cross-sectional section 21 and the profiled cross-sectional section 23, which transitions from a circular shape to a profiled contour.

The blank bottom 3 comprises an arc changing section 31 and a spherical section 32, wherein the arc changing section 31 is connected with the special-shaped section 23, gradually changes from a special-shaped contour to a circular contour, and is in arc transition connection with the spherical section 32. The maximum diameter d of the spherical segment 32 is not less than φ 8.

The principle of shortening the cooling time of injection molding of the invention is as follows: on the premise of not changing the gram weight of the conventional bottle blank, the cross section perimeter of the bottle blank structure is increased and the wall thickness of the bottle blank is reduced by changing the cross section shape of the bottle blank, so that the contact area between the bottle blank and a bottle blowing mold is substantially increased, the cooling time is shortened, the injection molding period and even the whole production period are shortened, the energy consumption is reduced, and the production efficiency is improved.

Based on the principle, the invention provides several embodiments of the bottle blank structure with the special-shaped section, and the embodiments are described in detail below.

Example 1

As shown in fig. 3a and 3b, in this embodiment, the cross-sectional shape of the shaped cross-section 23 is formed by an outer closing line 210a and an inner closing line 220a, and the outer closing line 210a and the inner closing line 220a are both zigzag-shaped and include a plurality of folding lines, and the folding lines of the outer closing line 210a and the inner closing line 220a are parallel to each other. The outer and

inner closing lines

210a and 220a composed of the folding lines include

several peaks

211a, 221a and

valleys

212a, 222 a.

To ensure that the stretch ratio of the preform structure with the irregular cross-section is equal to that of the preform structure with the circular cross-section shown in fig. 1a and 1b, the outer closed line 210a and the inner closed line 220a are respectively located near the outer ring and the inner ring of the circular cross-section, preferably, the outer folding line (i.e., the outer closed line 210a) and the inner folding line (i.e., the inner closed line 220a) respectively extend on the outer ring and the inner ring of the circular cross-section, and the area of the cross-section (hereinafter, referred to as "the inner-outer folding line cross-section") formed by the outer closed line 210a and the inner closed line 220a with the folding line shape and the area S of_{Ring (C)}The outer diameter m and the inner diameter n of the circular ring-shaped cross section are known, and the diameter D of a circle passing through the vertexes of all the wave crests 211a of the outer closed line 210a can be obtained by presetting the number of wave crests and α angles₁So as to establish a model of the inner and outer polygonal cross sections.

The process of establishing the model of the inner and outer polygonal sections is as follows:

if BE ═ AD, DF ═ BC, BG | | | | CD are taken, BE ═ DF ═ t, and t represents the shortest distance between 210a and the inner closed line 220a, i.e., the wall thickness of the irregular cross-section segment 23.

Let < ODA > be equal to beta and < OAD > be equal to alpha, then

And also

Wherein the content of the first and second substances,

β＝π-(θ+α) (2-4)

as a result of this, the number of the,

BM＝BCcosα (2-8)

AM＝AB+BM (2-9)

as a result of this, the number of the,

then a quadrangle S_□ABCDHas an area of

S_□ABCD＝S_□BCDG+S_ΔABG(2-11)

The area of the quadrangle □ ABCD requires an annular area S corresponding to the concentric angle θ_{Ring theta}Equal, annular area S_{Ring theta}Comprises the following steps:

order S_□ABCD＝S_{Ring theta}Is simplified to obtain

To ensure the draw ratio, the

Combine two formulas 2-13 and 2-14 to obtain

Get it solved

Thus, a model with an inside and outside polygonal cross section is obtained.

Example 2

As shown in fig. 4a and 4b, in this embodiment, the cross-sectional shape of the shaped cross-section 23 is formed by an outer closed line 210b and an inner closed line 220b, both the outer closed line 210b and the inner closed line 220b are corrugated, and the outer closed line 210b and the inner closed line 220b formed by the corrugated lines include a plurality of

peaks

211b, 221b and

valleys

212b, 222 b.

The ripple shape in this embodiment is substantially composed of a plurality of arc segments, the number of ripples is determined by the included angle corresponding to the arc segments, and the amplitude of the ripples is directly influenced by the position and the diameter of the center of the arc. As shown in fig. 4b, a method for generating a curve model will be described below by taking one of the curves as an example.

D1 and D2 are preset, D4 and D6 control the circular diameter of the outer lines of the corrugations, D3 and D5 control the circular diameter of the inner lines of the corrugations, and the size of theta is determined by the number of the corrugations.

To ensure that the stretch ratio of the preform structure with the irregular cross-section is equal to that of the preform structure with the circular cross-section shown in fig. 1a and 1b, the outer closed line 210b and the inner closed line 220b are respectively located near the outer ring and the inner ring of the circular cross-section, preferably, the outer folding line (i.e., the outer closed line 210a) and the inner folding line (i.e., the inner closed line 220a) extend respectively on the outer ring and the inner ring of the circular cross-section, and the area of the cross-section (hereinafter, referred to as "inner and outer corrugated cross-section") formed by the corrugated outer closed line 210b and the corrugated inner closed line 220b and the area S of the circular cross-section_{Ring (C)}Equals to give the number of wave crests x, D₁、D₂，D₃、D₄The unique corrugated section can be obtained by the three values in the step (a). The process of establishing the model of the inner and outer corrugated sections is as follows:

radius of the left end and the right end of the outer corrugation:

external corrugation tip radius:

order to

Wherein m and n are respectively the outer diameter and the inner diameter of the annular section bottle blank structure.

Circle D₄And D₅Tangency, the sum of radii equal AB:

2-26 to 2-29 solution in a combined vertical mode

The corrugated cross-sectional area is:

the corrugated section has the same area as the section of the circular ring:

S_{wave (wave)}＝S_{Ring theta}(2-33)

Circle D₃And D₆Tangency, the sum of radii equal AB:

2-20, 2-32-2-34 of the formula

Order to

Then there is

D₃＝2AB-D₆(2-39)

The thickness of the corrugation is:

thus, a model of the inner and outer corrugated cross-section was obtained.

Example 3

As shown in fig. 5a to 5c, in this embodiment, the sectional shape of the irregularly-shaped sectional segment 23 is constituted by an outer closed line 210c and an inner closed line 220c, the outer closed line 210c is a polygonal line, and the inner closed line 220c is a corrugated line. The outer and inner closing lines 210c and 220c, which are composed of folding lines, include

several peaks

211c, 221c and

valleys

212c, 222 c.

In order to ensure that the stretch ratio of the bottle preform structure with the irregular cross section is equal to that of the bottle preform structure with the circular cross section shown in fig. 1a and 1b, the outer closed line 210c and the inner closed line 220c are respectively positioned near the outer ring and the inner ring of the circular cross section, preferably, the broken line (i.e. the outer closed line 210c) and the corrugated line (i.e. the inner closed line 220c) respectively extend on the outer ring and the inner ring of the circular cross section, and the area of the cross section (hereinafter, referred to as the "outer-folded inner-corrugated cross section") formed by the outer closed line 210c and the corrugated inner closed line 220c is equal to the area of the circular cross section.

D1 is a preset value in the case of the inner and outer corrugated cross sections in embodiment 2, D3 and D6 are diameters of circles controlling the outer corrugations in the corrugated cross section, the size of the theta angle is determined by the number of wave crests, and gamma is an included angle between an outer folding line and a connecting line of the wave crests and the wave troughs. Only the number of wave crests, gamma, D1 and D2 are needed to determine the unique solution of D. The modeling process of the corrugated section inside the external fold is as follows:

let AO₃And d, m and n are respectively the outer diameter and the inner diameter of the ring. Taking the area of the annulus within the angle theta to be

As can be seen from the derived formula of the corrugated shape,

and also

∠AO₃E＝θ+α (2-46)

∠AEO₃＝180-θ-α-γ (2-47)

Then

sin∠AEO₃＝sin(θ+α+γ) (2-48)

Thus, the

And also

sin∠BEO₂＝sin∠AEO₃＝sin(θ+α+γ)，

sin∠O₂BE＝sin(θ+γ)，

Thus, the

Let the area of the quadrilateral ABCD and the annular area S of the concentric angle theta_{Ring theta}Equal, AB fluctuates around the original circular outer line, there is

Move item, have

Order to

Then there is

Order to

Get it solved

Thus, a model of the corrugated cross-section inside the outer folds is obtained.

Example 4

As shown in fig. 6a and 6b, in this embodiment, the sectional shape of the shaped section 23 is constituted by an outer closed line 210d and an inner closed line 220d, the outer closed line 210d is a polygonal line shape, and the inner closed line 220d is a circular shape. The outer closing line 210d composed of the folding lines includes several peaks 211d and valleys 212 d.

In order to ensure that the stretch ratio of the irregular-section bottle preform structure is equal to that of the circular-section bottle preform structure shown in fig. 1a and 1b, the outer closed line 210d and the inner closed line 220d are respectively located near the outer ring and the inner ring of the circular-section, preferably, the broken line (i.e., the outer closed line 210d) extends on the outer ring of the circular-section, and the area of the section (hereinafter referred to as "outer-folded inner-circular-section") formed by the broken-line-shaped outer closed line 210d and the circular inner closed line 220d is equal to the area of the circular-section. Knowing that the outer diameter m and the inner diameter n of the circular ring-shaped section and the size of theta are determined by the number of corrugations, under the condition of meeting the two conditions, giving the number x and alpha of wave crests to obtain a model of the externally-folded and internally-circular section, wherein the model establishing process is as follows:

cross-sectional area of bottle preform with annular cross-section corresponding to concentric angle theta

Order to

Get it solved

Wherein the content of the first and second substances,

thus, a model of an outwardly-folded inner circular cross-section is obtained.

According to the invention, the conventional bottle blank structure with the annular section is improved, and the annular section of the bottle blank structure with the annular section is changed into the special-shaped section on the premise of not changing the gram weight of the bottle blank, so that the section perimeter of the bottle blank structure is increased, the contact area between the bottle blank and a bottle blowing mold is substantially increased, and the cooling time of injection molding of the bottle blank can be effectively shortened; and the wall thickness of the bottle blank with the special-shaped cross section is reduced compared with that of the bottle blank with the conventional annular cross section, so that the bottle blank with the special-shaped cross section has better heat conductivity, when the bottle blank is blown into a bottle, the bottle blank is uniformly preheated, the heating time is shortened, and the energy consumption of heating the bottle blank and the energy consumption of bottle blowing pressure are reduced. In addition, the change of the sectional shape of the bottle blank does not affect the stretch ratio of the bottle blank, and the stretch ratio is kept unchanged from the original conventional bottle blank, so that the blow molding property of the bottle is kept unchanged, and the bottle with the same quality requirement can be formed by blow molding.

The following is a comparative test of the irregular-section bottle preform structure of the present invention and the conventional circular-section bottle preform structure in the bottle preform injection molding and blow molding processes.

Test environment of injection molding:

cooling effect of injection molding:

in the test, the temperature of 22 groups of bottle blanks is measured, and the result is shown in fig. 7 under the test environment, the average maximum temperature of the conventional bottle blank after cooling is 80.2 ℃, after the abnormal point is removed, the maximum average temperature of the inner and outer polygonal-section bottle blanks (referred to as "inner and outer polygonal-section bottle blanks") after cooling is 67.78 ℃, and the maximum average temperature of the outer and inner polygonal-section bottle blanks (referred to as "inner and outer polygonal-section bottle blanks") after cooling is 62.175 ℃.

As shown in the infrared cloud chart of fig. 8, it can be known that the positions of the inside-outside zigzag-shaped bottle blank and the outside-outside zigzag-shaped bottle blank with the highest temperature are at the blank body parts of the bottle blanks, the cooling efficiency of the bottle blanks with the two special-shaped structures is better than that of the conventional 22.28g bottle blank, and the cooling efficiency is improved by more than 15.49% compared with that of the conventional bottle blank.

According to the test results of the injection molding process, it can be obtained that: compared with the prior bottle blank with the annular cross section, the bottle blank with the special-shaped cross section has the advantages that the temperature is reduced more, the cooling time is shorter, and the cooling efficiency is higher.

And (3) blow molding test:

and carrying out blow molding tests on the conventional bottle blanks with the annular cross sections, the bottle blanks with the inside and outside fold line shapes and the bottle blanks with the outside fold and inside circular shapes, and carrying out heating analysis and comparison on the bottle blanks.

As shown in FIG. 9, when the three preforms were heated for 103 seconds under the same heating conditions, the temperatures of the three preforms were measured. In the picture shown in fig. 9, the left side is a conventional bottle preform with a circular cross section, the middle is a bottle preform with an inside-outside zigzag shape, and the right side is an outside-folded inside-circle bottle preform. It can be seen that the temperature of the externally folded and internally folded round preform is 109.5 deg.c, the temperature of the internally and externally folded line-shaped preform is 104.8 deg.c, and the temperature of the conventional ring-shaped cross-section preform is the lowest, 100.3 deg.c. Therefore, under the same heating condition, compared with the existing bottle blank with the annular cross section, the bottle blank with the special-shaped cross section has the advantages that the temperature rise is higher, the bottle blank is easier to heat, the heating time is shortened, and the energy consumption in the heating process is effectively saved.

Blow molding effect and depressurization test:

for the conventional bottle blank with the annular cross section, the blowing pressure is usually required to be more than 32MPa to meet the bottle blowing quality requirement, and the bottle blank with the special-shaped cross section can meet the bottle blowing quality requirement when the blowing pressure is 30 MPa. The effect of PET was observed by reducing the blowing pressure under the same heating conditions, and evaluated at a 5 point full scale, and the evaluation results were as follows:

according to the pressure reduction test, the special-shaped section bottle blank of the invention has lower required blow molding pressure compared with the existing annular section bottle blank, and can meet the blow molding quality requirement, thereby saving the energy consumption in the blow molding process.

In conclusion, compared with the prior art, the bottle blank with the special-shaped cross section is easier to cool and heat and has better heating uniformity, the efficiency of each process of injection molding, preheating and blow molding of the bottle blank is obviously improved, the required processing period is obviously shortened for the production and processing of the whole plastic bottle, and the production efficiency is greatly improved.

The above detailed description merely describes preferred embodiments of the present invention and does not limit the scope of the invention. Without departing from the spirit and scope of the present invention, it should be understood that various changes, substitutions and alterations can be made herein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. The scope of the invention is defined by the claims.

Claims

1. The utility model provides a dysmorphism cross section bottle base structure, includes at the bottom of bottleneck, base body, the base, its characterized in that:

the blank body comprises an annular section, a section change section and a special-shaped section, the annular section is connected with the bottle mouth, the special-shaped section is connected with the blank bottom, the section change section is a transition section between the annular section and the special-shaped section,

compared with the annular-section bottle blank structure with the same length and the same gram weight of the special-shaped-section bottle blank structure, the annular-section bottle blank structure is provided with an annular section, the circumference of the special-shaped section is larger than that of the annular section on the premise that the bottle blowing stretching ratio of the special-shaped-section bottle blank structure is equal to the bottle blowing stretching ratio of the annular-section bottle blank structure, and the wall thickness of the special-shaped-section bottle blank structure is smaller than that of the annular-section bottle blank structure.

2. The shaped cross-section preform structure of claim 1, wherein the shaped cross-section of the shaped cross-section preform structure has an area equal to an area of the annular cross-section preform structure.

3. The irregular-section bottle preform structure as claimed in claim 2, wherein the folding lines constituting the closed line are distributed on the outer circular ring of the circular-ring-shaped section.

4. The profiled cross-section bottle preform structure of claim 3, wherein the inner closed line of the profiled cross-section is circular, corrugated or dog-leg shaped.

5. The contoured cross-section preform structure of claim 4, wherein the fold line forming said outer closure line is parallel to the fold line forming said inner closure line.

6. The profiled cross-section bottle preform structure of claim 1, wherein said preform base comprises a circular arc variation section and a spherical section, said circular arc variation section being connected to said profiled cross-section.

7. A method for forming a bottle blank structure with a special-shaped section is characterized by comprising the following steps:

s1 provides a conventional bottle preform structure, which comprises a bottle mouth, a preform body, a preform bottom,the blank body is in a hollow cylindrical shape and is provided with a circular ring-shaped section consisting of an outer closed line and an inner closed line, the outer diameter and the inner diameter of the circular ring are m and n respectively, and the area of the circular ring-shaped section is S_{Ring (C)}；

specifically, the number of wave crests is preset, an included angle theta between the connecting line of the wave crests and the wave troughs and the center of the circular ring shape is obtained, and a special-shaped section model is established on the premise that the area of the special-shaped section is not changed relative to the area of the circular ring-shaped section;

8. The method of forming a shaped cross-section bottle preform structure as recited in claim 7, wherein in the step S2, the folding line constituting the outer closing line is made to extend on the outer circular ring of the circular ring-shaped cross-section.

9. The method for forming a bottle preform structure with a profiled cross section as claimed in claim 8, wherein the shape of the inner closed line of the circular cross section is changed into a corrugated shape or a dogleg shape.

10. The method of forming a shaped cross-section preform structure of claim 9, wherein the inner closing line of the circular cross-section is changed to a polygonal line shape such that a polygonal line of the inner closing line extends on the inner circle of the circular cross-section and such that a polygonal line of the outer closing line is parallel to a polygonal line of the inner closing line.