Description:FIELD OF INVENTION:
[001] The present invention relates to making containers, and more
particularly, to producing the plastic containers with patterns on inner surface.
BACKGROUND 5 OF THE INVENTION:
[002] Plastic containers are widely used for number of commercial
purposes. The containers may be in the form of cylindrical bottles for storage of
liquid and solids. In most of the uses, the strength of the container is critical.
Smart selection of material of construction takes care of the strength factor.
10 However, to provide further strength to the container, reinforcing ribs are
structurally included around the body of the container. Most typically, such
reinforcing ribs are included at the outer surface of the body of the container.
However, with this, the outer surface becomes uneven, and not so adaptable for
labeling and decoration purpose.
15 [003] To overcome said issue, some selected producers started the
practice of incorporating the reinforcing ribs at an inner surface of the container.
The current applicant is one such producer and has been granted patent IN403144.
In the said patent, wherein the container & a method of forming the same is
disclosed, the current applicant has demonstrated that the inclusion of reinforcing
20 ribs on the inner surface has increased the compression strength of the container
for the constant volume and weight.
[004] The applicant herein proposes a method by which plastic
containers having further greater compression and hoop strength may be produced
effectively.
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SUMMARY OF INVENTION:
[005] It a primary object of the invention to provide greater compression
and hoop strength to the plastic container.
[006] It is an object of the invention to provide a method by which the
30 plastic container having patterns on its inner wall may be produced.
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[007] The method of producing the container comprises steps of:
extruding one or more layers of molten thermoplastic around a mandrel;
subjecting the layers for programming; forming a parison with combination of
circumferential & longitudinal grooves; and blowing compressed air into the
formed parison to form the container with combination of 5 circumferential &
longitudinal reinforcing ribs on the inner wall.
[008] The longitudinal reinforcing ribs on the inner wall of the container
correspond to plurality of longitudinal indentations provided on a mandrel,
whereas the circumferential reinforcing ribs correspond to circumferential grooves
10 provided during processing (e.g. parison programing). For example, during
parison programming, the gap between die and mandrel may be changed to
change the thickness of the parison.
[009] In an embodiment, the longitudinal indentations on the mandrel are
present in range of 4 to 64. The adjacent longitudinal indentations are spaced apart
15 in range of 0.5 mm to 10 mm. Each of the longitudinal indentations has depth of
0.1 mm to 10 mm, and width of 0.1 mm to 10 mm.
[010] In the same embodiment, the circumferential grooves are present in
range of 1 to 15, wherein adjacent circumferential grooves are spaced apart in
range of 1 mm to 500 mm. Each of the circumferential groove has depth of 0.1
20 mm to 10 mm, and width of 0.1 mm to 10 mm.
[011] The thermoplastic material is selected from High Density Poly
Ethylene (HDPE), Low Density Poly Ethylene (LDPE), Linear Low Density Poly
Ethylene (LLDPE), Polypropylene (PP), their blends, PCR (Post-Consumer
Recycled Material or Post Consumer Resin) and such.
25 [012] The present invention also discloses a container which is produced
by the method and the apparatus disclosed above.
[013] The said container comprises a neck, and a body made of
thermoplastic material. The container has an inner surface provided with a
combination of circumferential & longitudinal reinforcing ribs.
30 [014] The longitudinal reinforcing ribs are present in range of 4 to 64.
The adjacent longitudinal ribs are spaced apart in range 2 to 50 mm. Each of the
4
longitudinal indentations has depth of 0.05 mm to 8 mm, and width of 0.3 mm to
30 mm
[015] The circumferential ribs are present in range of 1 to 15, wherein
adjacent ribs are spaced apart in range of 5 to 300 mm. Each of the
circumferential ribs has depth of 0.05 mm to 8 mm, and has 5 width of 0.3 mm to
30 mm.
[016] The container described above show increased compression
strength in range of 10% to 50%.
10 BRIEF DESCRIPTION OF DRAWINGS:
[017] Following figures illustrate various aspects of the present
invention.
Figure 1(a) shows a divergent mandrel with longitudinal indentations.
Figure 1(b) shows a convergent mandrel with longitudinal indentations.
15 Figure 2 shows a parison forming with circumferential grooves.
Figure 3 represents an example of the finished container, in the form of bottle.
DETAILED DESCRIPTION OF THE INVENTION:
[018] Accordingly, the present invention discloses a method and an
20 apparatus for producing containers. While describing the invention, certain terms
and expressions are recognised and understood by the persons skilled in the art.
The present description does not intend to deviate from those meanings.
[019] The present description describes various aspects of the present
invention, including a preferred embodiment and its alterations. Some of the
25 aspects are supported by the figures. However, the description as well as the
figures do not intend to restrict the scope of the invention. Any variation in the
description as well as figures introduced by any person, including a person skilled
in the art, will be falling in the extent of the present invention.
[020] Accordingly, a method of producing containers is described herein,
30 which comprises: extruding one or more layers of molten thermoplastic around a
mandrel; subjecting the layer for programming; forming a parison with
5
combination of circumferential & longitudinal grooves on inner side; and blowing
compressed air into the formed parison to form the container with combination of
circumferential & longitudinal reinforcing ribs on inner wall.
[021] The said thermoplastic to be extruded may be selected from High
Density Poly Ethylene (HDPE), Low Density Poly Ethylene 5 (LDPE), Linear Low
Density Poly Ethylene (LLDPE), Polypropylene (PP), their blends, PCR (Post
Consumer Recycles) and such.
[022] The parison is formed between die and the mandrel unit, wherein
the parison has a combination of longitudinal and circumferential grooves on it.
10 The said longitudinal grooves on the parison are a consequence of the indentations
provided on the mandrel as shown in Figure 1, whereas said circumferential
grooves are provided during processing step as shown in Figure 2. After the
molten thermoplastics are transferred through the mandrel, the longitudinal and
circumferential grooves are formed onto the inner side of the parisons.
15 [023] It may be noted that Figure 1(a) represents a divergent madrel,
whereas Figure 1(b) represents a convergent mandrel. The mandrels in the said
figures may be used as per the requirement.
[024] The formed parisons are captured between molds and are either
blown in reciprocating blow molding machine or transferred to blowing station in
20 continuous blow molding machine, wherein the compressed air is blown into the
formed parisons, inflating the parisons into the containers and cooled to form the
containers as a final product with circumferential and longitudinal ribs on the
inner surface of the containers.
[025] In an embodiment, the longitudinal indentations on the mandrel are
25 present in range of 4 to 64. In a more preferred embodiment, the longitudinal
indentations are in the range of 20 to 40.
[026] In an embodiment, the adjacent longitudinal indentations are
spaced apart in range of 0.5 mm to 10 mm. In a preferred embodiment, the
adjacent longitudinal indentations are spaced apart at a distance ranging from 0.7
30 mm to 1.5 mm.
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[027] Each of the longitudinal indentations has depth of 0.1 mm to 10
mm, and width of 0.1 mm to 10 mm. In a preferred embodiment, the longitudinal
indentations have depth in the range of 0.2 mm to 1 mm and width of 0.4 mm to
1.5 mm.
[028] In an embodiment, the circumferential grooves are 5 present in range
of 1 to 15. In a preferred embodiment, the circumferential indentations are present
in range of 2 to 6.
[029] In an embodiment, the adjacent circumferential grooves are spaced
apart in range of 1 mm to 500 mm. In a preferred embodiment, the adjacent
10 circumferential grooves are spaced apart in range of 20 mm to 300 mm.
[030] In an embodiment, the circumferential grooves have depth of 0.1
mm to 10 mm and width of 0.1 mm to 10 mm. In a preferred embodiment, each of
the circumferential groove has depth of 0.2 mm to 1 mm and width of 0.4 mm to
1.5 mm.
15 [031] The container so formed has reinforcing longitudinal &
circumferential ribs on its inner wall, as shown in Figure 3, which correspond to
the longitudinal indentations inscribed on the mandrel and circumferential
grooves provided by parison programming.
[032] In a preferred embodiment, the longitudinal ribs are present in
20 range of 4 to 64. The longitudinal ribs are spaced apart in range of 2 mm to 50
mm. The longitudinal ribs have depth of 0.05 mm to 8 mm and width of 0.3 mm
to 30 mm. The circumferential ribs are present in range of 1 to 15. The
circumferential ribs are spaced apart in range of 5 mm to 300 mm The
circumferential ribs have depth of 0.05 to 8 mm and width of 0.3 mm to 30 mm.
25 [033] The container so formed has greater compression strength. In an
exemplary embodiment, the compression strength of the so formed container is
increased by 10% to 50%. This allows light weighting of the container by 5% to
25% with equivalent compression strength.
[034] It may be noted that, in the context of the present invention, the
30 container may be any container adapted to store liquid or semi-liquid or solid like
powders, pills, etc. Therefore, the container could be a bottle in which a mineral
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water, or a beverage or personal care products or homecare products may be
stored. Further, in the context of the present invention, the container may be any
container adapted to store pharmaceutical or medicinal liquid. As such, there is no
restriction in which field the present container is used. The container may be used
to store any suitable liquid or solid, where compression strength 5 of the container
matters. , Claims:A method of producing containers comprises
extruding one or more layers of molten thermoplastic around a
mandrel;
forming a parison with combination of circumferential &
longitudinal grooves, wherein said longitudinal grooves correspond to
plurality of indentations inscribed on a mandrel and said circumferential
grooves correspond to plurality of circumferential indentations formed
during parison programming; and
blowing compressed air into the formed parison to form the
container with combination of circumferential & longitudinal reinforcing
ribs on an inner wall of the container.
2. The method as claimed in Claim 1, wherein the longitudinal indentations
are present in range of 4 to 64.
3. The method as claimed in Claim 2, wherein the longitudinal indentations
are in the range of 20 to 40.
4. The method as claimed in Claim 1, wherein the adjacent longitudinal
indentations are spaced apart at a distance ranging from 0.5 mm to 10 mm.
5. The method as claimed in Claim 4, wherein the adjacent longitudinal
indentations are spaced apart at a distance ranging from 0.7 mm to 1.5
mm.
6. The method as claimed in Claim 1, wherein the longitudinal indentations
have depth of 0.1 mm to 10 mm.
7. The method as claimed in Claim 6, wherein the longitudinal indentations
have depth in the range of 0.2 mm to 1 mm.
8. The method as claimed in Claim 1, wherein the longitudinal indentations
have width of 0.1 mm to 10 mm.
9. The method as claimed in Claim 8, wherein the longitudinal indentations
have width of 0.4 mm to 1.5 mm.
10. The method as claimed in Claim 1, wherein the circumferential grooves
are present in range of 1 to 15.
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11. The method as claimed in Claim 10, wherein the circumferential grooves
are present in range of 2 to 6.
12. The method as claimed in Claim 1, wherein the circumferential grooves
are spaced apart in range of 1 mm to 500 mm
13. The method as claimed in Claim 12, wherein the circumferential grooves
are spaced apart in the range of 20 mm to 300 mm.
14. The method as claimed in Claim 1, wherein the circumferential grooves
have depth of 0.1 mm to 10 mm.
15. The method as claimed in Claim 14, wherein the circumferential grooves
have depth of between 0.2 mm to 1 mm.
16. The method as claimed in Claim 1, wherein the circumferential grooves
have width of 0.1 mm to 10 mm.
17. The method as claimed in Claim 16, wherein the circumferential grooves
have width of 0.4 mm to 1.5 mm.
18. The method as claimed in Claim 1, wherein the thermoplastic material is
selected from High Density Poly Ethylene (HDPE), Low Density Poly
Ethylene (LDPE), Linear Low Density Poly Ethylene (LLDPE),
Polypropylene (PP), their blends, PCR and such.
19. The method as claimed in Claim 1, wherein compression strength of the
container is increased in range of 10% to 50%.
20. A container comprising a neck, and a body made of thermoplastic
material; wherein an inner surface of the body is provided with a
combination of circumferential & longitudinal reinforcing ribs.
21. The container as claimed in Claim 20, wherein the longitudinal ribs are
present in range of 4 to 64.
22. The container as claimed in Claim 20, wherein the longitudinal ribs are
spaced apart in range of 2 mm to 50 mm.
23. The container as claimed in Claim 20, wherein the longitudinal ribs have
depth of 0.05 mm to 8 mm.
24. The container as claimed in Claim 20, wherein the longitudinal ribs have
width of 0.3 mm to 30 mm.
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25. The container as claimed in Claim 20, wherein the circumferential ribs are
present in range of 1 to 15.
26. The container as claimed in Claim 20, wherein the circumferential ribs are
spaced apart in range of 5 mm to 300 mm.
27. The container as claimed in Claim 20, wherein the circumferential ribs
have depth of 0.05 mm to 8 mm
28. The container as claimed in Claim 20, wherein the circumferential ribs
have width of 0.3 mm to 30 mm.
29. The container as claimed in Claim 20, wherein compression strength of the
container is increased by 10% to 50%.
30. The container as claimed in Claim 20, wherein the thermoplastic material
is selected from High Density Poly Ethylene (HDPE), Low Density Poly
Ethylene (LDPE), Linear Low Density Poly Ethylene (LLDPE),
Polypropylene (PP), their blends, PCR and such.