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CA1171369A - Composite container having spin bonded ends - Google Patents

Composite container having spin bonded ends

Info

Publication number
CA1171369A
CA1171369A CA000435606A CA435606A CA1171369A CA 1171369 A CA1171369 A CA 1171369A CA 000435606 A CA000435606 A CA 000435606A CA 435606 A CA435606 A CA 435606A CA 1171369 A CA1171369 A CA 1171369A
Authority
CA
Canada
Prior art keywords
end closure
spin
closure member
layer
fin portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000435606A
Other languages
French (fr)
Inventor
Stephen E. Woerz
Travis K. Canup
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Officemax Inc
Original Assignee
Boise Cascade Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US06/288,344 external-priority patent/US4353761A/en
Application filed by Boise Cascade Corp filed Critical Boise Cascade Corp
Priority to CA000435606A priority Critical patent/CA1171369A/en
Application granted granted Critical
Publication of CA1171369A publication Critical patent/CA1171369A/en
Expired legal-status Critical Current

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Abstract

ABSTRACT OF THE INVENTION
A composite container is disclosed having a synthetic plastic end closure member spin-bonded to the thermoplastic synthetic plastic inner liner layer of a composite container body wall. The synthetic plastic end closure member includes annular downwardly depending inner fin and outer chime portions which are concentrically spaced to define therebetween an annular groove. One of the body and end members is rotated relative to the other member when they are in spaced vertical alignment, whereupon the members are axially displaced together to wedge the upper end of the body member into the annular groove of the end closure member. During this spin bonding process, the fin portion of the end closure member is supported against radial inward deflection, whereby the spinning frictional engagement between the fin portion of the end closure member and the inner liner layer of the body member causes softening and subsequent bonding of the fin portion to the inner liner layer.

Description

3 ~ ~
This is a aivisional application of copendiny Canadian application 393,203 filed December 2~, 1981.
BACKGROUND OF THE INVENTION
_ The present invention relates to a composite container body member having a synthetic plastic end closure member spin bonded to one end thereof. The concept of spin bonding, or friction welding as it is alternately termed, of two synthetic plastic parts, for instance a container body and an end closure or cap member, is known, as disclosed in the. patent to Brown, Nos. 3,297,504 and 3,499,068, Jones, No. 3,712,497, and Standley, No. 4,075,820. Generally, the two synthetic plastic parts are of substantially equal thickness so that when they are spinning in frictional engagement, the heat created is sufficient to soften and subsequently bond the parts.
~ wing to the relatively small thickness of the inner liner layer, the spin bonding of a synthetic plastic end closure member to a composite container body member presents certain inherent problems. More particularly, the end closure member is generally at least 50 times thicker than the thermoplastic inner liner layer, and in the past, prior attempts to spin bond the two parts together have been generally unsuccessfull. Thus, the thin thermoplastic inner layer is often either torn or disturbed from its engagement with the composite body wall when it is displaced ,~ .

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into spinning frictional engagement with thicker plastic end closure member. Therefore, prior to the invention, it was difficult to produce a continuous fluid tight seal in a composite container including a synthetic plastic end closure member spin bonded to the thermoplastic inner liner layer of a composite body member.
Furthermore, a conventional plastic end member which is bonded to a container body member has a tendency, when stressed during filling and handling of the container, to flex - 10 in such a manner that it peels away from the sides of the ; container where it is in bonding engagement therewith, thereby destroying the integrity of the seal between the end closure ; and body members.
According to one aspect, a composite container is provided including a novel synthetic plastic end closure member having annular, downwardly depending inner fin and outer chime portions that are concentrically spaced to define an annular groove. Before the engagement of the end closure member with the body member, the fin portion of the end closure Imember is, on its outer surface, inwardly tapered. Consequentl~, the end closure member resists the tendency to flex in such a manner as to peel away from the composite body wall` member, and instead flexes in such a manner that the central panel portion of the end member absorbs the tenslle stresses directed on the end closure member and the end closure member remains intact with the composite body member.
Therefore, in accordance with the present invention there is provided a spin bonded composite container comprising:
a vertically arranged cylindrical composite body member including a fibrous body wall layer, an inner thermoplas-tic ~ cr/

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synthetic plas-tic line layer, and an outer label layer; ana a syn-thetic plastic end closure member spin bonded to one end of the body member, the end closure member including:
a circular center panel portion closing the upper end of the body member; an inner annular sealing L in portion extending downwardly from the center panel portion adjacent the inner liner layer, the sealing fin portion being friction spin-bonded to the inner liner layeri and an outer annular chime portion extending downwardly from the center panel portion in spaced concentric relation relative to the sealing fin portion adjacent the outer label layer.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional objects and advantages of the present invention will become apparent from the following detailed description when viewed in light of the accompanying drawings in which:

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~7~3~9 Fig. 1 is a detailed cross-sectional view of a pair of stacked composite containers of the present invention;
Fig. 2 is a detailed cross-sectional view of a pair of stacked end closure members in accordance with the present invention Fig. 3 is a top sectional view of one of the end closure members of Fig. 2.
Fig. 4 is a cross-sectional view illustrating one embodiment of the flaring process;
Fig. 5 is a cross-sectional view of the spin bo~ding apparatus of the present invention;
Figs. 6 and 7 are cross-sectional and bottom plan views, respectively, of the rotary chuck means of Fig. 5;
Figs. 8 and 9 are sectional and bottom plan views, respectively, of therotary mandrel means of Fig. 5; and Figs. 10, 11 and 12 are progressive cross-sectional views of the spin bonding process in accorance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION
With reference to Fig. 1, composite container 10 includes a cylindrical vertically arranged body member 12 and synthetic plastic end closure member 14 spin bonded thereto.
Body member 12 includes at least one fibrous body wall layer 16, a thermoplastic synthetic plastic inner liner layer 18 and an outer label layer 20.

~ ~7~3~9 End closure member 14 includes annular downwardly depending concentrically spaced inner sealing fin and outer chime portions, 14a and 14b, respectivelyt which define therebetween an annular groove 26. The upper extremity of body member 12 is located in annular groove 26, fin portion 14a and thermoplastic inner liner layer 18 being spin bonded into sealing relation. In accordance with an important feature of the pxesent invention, the thickness of the fin portion 14a is on the order of 20 to 50 times that of the liner layer I8. More particularly, for reasons of economy, the liner Iayer 18 is maintained relatively thin, but for reasons of strength, a fin portion of substantial thickness is desired. Thus, the fin and chime connecting portions of the end closure member must be of sufficient strength to maintain the integrity of the bond not only during flexing of the central portion of the end relative to the fin and chime portions, but also during stacking of the containers. To this end, the end closure member 14 further includes an annular upwardly extending portion 14c which allows the composite containers to be stacked one upon another in a positive manner. A plurali*y of circumferentially spaced radial strengthening ribs 14d ~Fig. 3~ extend inwardly from the inner surface of stacking portion 14c. ~he circular central panel portion 14e of the end closure member also includes an annuIar rib portion 14f. The radial and annuIar rib portions 14d and 14f, respectively~ contribute to the strength of the end closure member.

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All corners of.the-end clo'sure member are rounded in such a manner as to eliminate stresses within. When the end closure member is stressed during fil'ing of the composite container or 'subsequent handling thereof, the circular central panel portion 14e flexes relative to the fin and chime portions 14a and 14b~
respectively, which flexing elimir,ates the prior tendency of the end member to peel away from the body member.in the seal area.
A plurality of the end closure members 14 may be stacked one upon another in a positive manner as is shown in Fig. 2. This is especially convenient when shipping the ends from manufacturer to user in that it eliminates costly air space shipping.
Prior to its connection with body member 12l t~e fin portion 14a of the end closure member is vertically inwardly tapered on its outer surface, as shown in Fig. 2. The tapered fin portion forms~an acute angle of approximately
2.5 - 5.0 degrees with the vertical. This taper feature is very important to the integrity : of the final spin-bonded seal between the end closure and body mèmbers in ~hat it allows sufficient space for the excess molten plastic which is formed in the spin bonding process to flow downwardly without distu~bing the thin thermoplastic inner liner layer of.the body . 30 member.
The method of spin bonding~ and the . apparatus employed therefor, are both important . to the success of the final spin'bonded composite container of the present invention.
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To ensure a close, tight fit between the end closure and body members, it is necessary to size the upper extremity of the body member to a controlled dimension and slightly round O L f the upper edge. In accordance with another important feature of the invention, the sizing and rounding operations are achieved in a single flarin~ step as demonstrated in Fig. 4. A
cylindrical flaring die 40 is inserted in the upper extremity of body member 12, which die 40 includes an upwardly, outwardly tapered circumferential portion 40a which merges at its upper end in an outward, slightly concave surfce 40b. Circumferential surface 40a fits closely to body member 12 and as it is inserted therein, it sizes and rounds body member 12 as it flares the upper extremity 12a. Any conventional tooling which achieves the same flaring of the body member may be substituted for flaring die 40. The flaring operation eliminates any variation in the diameter of the upper end of body member 12 due to materials, machinery and weather conditions. ~enerally, the flaring increases the inside diameter of the body member by approximately 0.01 inches.
The body member 12 is releasably secured to stationary, vertically arranged central mandrel means 50 which is inserted therein as shown in Fig. 5. Clamp means 52 - 30 retain body member 12 against central mandrel means 50, thereby preventin~ movement of body member 12 rela~ive to the central mandrel means.
Other securing means, such a~s vacuum suction ; ' ~7 ~36~

means or expansible mandrel means, may be substituted for the clamp means shown in Fig. 5.
- Rotary mandrel means 54 are rotatably connected with central mandrel means 50 and include disk portion 54a and shaft portion 54b which is journalled in the upper end of the central màndrel means 50.' The rotary and central mandrel means include a plurality of vertical air passages 60 and'62, respectively, the passages 62 being in communication with atmosphere near the base of the central mandrel means 50. These air passages may be of configurations other than vertical as long as they form an air passage during the spin bonding process from the top of the rotary mandrel means through the central mandrel means to the atmosphere.
A cross-sectional view of rotary mandrel means 54 is shown in Fig. 8, and a top view of the same is shown in Fig. 9. The diameter of dis~ portion 54a is generally equal to the inner diameter of sealing fin portion 14a of the end closure member. The disk portion is important to the success of the spin bonding process, as ~ill be explained in detail below.
A compressible member 64 is mounted on the upper surface of disk portion 54a of the rotary mandrel means, which member 64 is of a suitable resilient material, such as foam rubber or the like.
Referring to Figs. 5-7, a vertically-displaceable rotary chucX'means 70'is axially aligned in vertically spaced relation above t~e central and rotary mandrel means 50'and ~7~3~9 _9~

54, which chuck means is driven by rotary drive means 71 at a rotational velocity sufficient to effect spin bonding (i.e., about 3000 rpm).
The rotary chuck means includes means for mounting a plastic end closure member 14 on the lower surface thereof. In the illustrated embodiment, the mounting means includes a vacuum source 73 that communicates via passages 76 ànd orifices 78 with annular groove 72 contained in the lower surface of the rotary chuck'means 70, thereby holding the end closure member in place.

Operation In operation, the container body lS member 12 is mounted on central mandrel means 50 by clamp means 52 so that there is no vertical or rotational movement of bo'dy member 12 relative to central mandrel means 50, and end closure member 14 is mounted on rotary chuck means 70.
Rotary chuck means 70, with end closure member 14 mounted thereon as shown in Fig.
5, is rotated at a rotational velocity sufficient to effect the desire spin bonding (i.e., about 25 3000 rpm). While rotary chuck means 70 is rotating, it is vertically, axially displaced downwardly to cause the lower surface of cixcular central panel portion'32 of the end closure member to engage compressible material 64, thereby causing rotary mandrel means 54 to spin in bearings 55 at the rotational veloci'ty of the rotary chuck means 70. Therefore, as rotary chuck means 70 is further displaced 1~7~3~9 downwardly, compressible material 64 is compressed and sealing fin portion 14 of the end closure member is supported, as shown in Fig. 10, by disk portion 54a of the rotary mandrel means which is rotating at a velocity less than or equal to the velocity of the end closure member.
Disk portion 54a supports sealing fin portion 14a against inward ra~ial deflection or scuffing as the rotating end closure member is lowered into engagement with the body member.
The rotary driving mechanism of therotary chuck means is disengaged to allow the chuck means to spin freely. With reference to Fig. 11, end closure member 14 is than quickly inserted in the upper end of body member 12 such that the flared upper extremity of body member 12 i5 progressively wedged tightly within annular groove 26 contained in the end member, and sealing fin portion 14 is wedged between the thermoplastic inner liner layer 18 of the body member and disk portion 54a of the rotary mandrel means. The spinning frictional engagement between the thermoplastic inner liner and the plastic sealing fin portion creates heat sufficient to soften and subsequently spin bond the contiguous thermoplastic materials. The rotary chuck means is then removed from the end~closure member.
According to an important feature o~ the invention, owing to the support of sealing fin portion 14a and its downwardly inwardly tapered ou~ere surface, the excess molten plastic ~reated during the spin bonding ~lows downwardly as shown in Fig. 11 7 thereby to provide an even thickness and to prevent thermoplastic 11713~g --ll--inner liner layer 18 from tearing as shown in Fig. 12. A strong, liquid-tight spin-bonded seal is thereby provided in a composite container.
Although in the illustrated embodlment the end closure member is spun while the body member is maintained stationary, it is within the scope of the present invention, of course, tc hold the end closure member stationary and spin the body member. Simil`arly, while in the described method the end closure member is vertically axially displaced while the body member is held stationary, it is eqully within the scope of the invention to displace the body member and to hold the end closure member stationary.
O~ce the spin bonding has occurred, clamping means 52 of the central mandrel means are removed from body member 12,whereby the body member, with the end closure member spin bonded thereto, is removed fxom the central mandrel means. To this end, air passages 60 and 62 are provided which prevent a vacuum from forming between the rotary and central mandrel means~and the end and body members.
A metal end closure member (not shown) is connected with the bottom end of body member 12 in any conventional manner once the composite container is filled. Of course, it is within the scope of the present invention to reverse the container so that the synthetic plastic end closure member is spin-bonded to the bo*tom of the vertically arranged body wall, and the metal end closure member is su~sequently applied to the upper end of the container.

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The spin bonded seal between the plastic end closure member and the body member is sufficiently strong to withstand any stress created by the conventional bottom end closing operation. Tests have been established that the connection between the inner liner layer and the spin bonded synthetic plastic end is 3 to 4 times stronger than a conventional rolled seam connection between a composite body wall and a metal end closure member. In this regard, it is to be noted that an upwardly directed force on the central portion of the end 14 will produce bending of the end at the portion thereof between the stacking rib 14c and the lS fin portion 14a, thereby maintaining the integrity of the seal between the fin portion 14a and the inner liner layer 18 (which seal is sub~ected to forces of shear rather than forces of peel).
To this end, the junctions of the stacking rib 14c to the upper surface of the end are preferably radiused.
The inner liner layer 18, which generally has a thickness of from .0005" to about .003~"~
is formed from a conventional heat sealable thermoplastic synthetic plastic material, such as polyofin, a styrene, a polycarbonate, an acrylic polymer, or the like.
As shown in Fig. 10, the taper angle of the outer sur~ace of the fin portion 14a is slightly greater relative to the vertical than the angle of the flared upper e~tremity 12a of the composite body member 12.

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- ~ 1713B9 While the preferred forms and embodiments of -the invention have been illustrated and described, it will be apparent.that modifications may be made without deviating from the scope of the invention set forth above.
Method and apparatus embodiments disclosed herein are also disclosed and claimed in Canadian application 393,203.

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Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A spin bonded composite container comprising:
(a) a vertically arranged cylindrical composite body member including a fibrous body wall layer, an inner thermoplastic synthetic plastic line layer, and an outer label layer; and (b) a synthetic plastic end closure member spin bonded to one end of said body member, said end closure member including:
(1) a circular center panel portion closing the upper end of said body member;
(2) an inner annular sealing fin portion extending downwardly from said center panel portion adjacent said inner liner layer, said sealing fin portion being friction spin-bonded to said inner liner layer; and (3) an outer annular chime portion extending downwardly from said center panel portion in spaced concentric relation relative to said sealing fin portion adjacent said outer label layer
2. A spin bonded composite container as defined in 1, wherein said end closure member further includes:
(4) an annular stacking rib portion extend-ing upwardly from said circular center panel portion, the diameter of said stacking rib portion being less than that of said sealing fin portion; and (5) a plurality of circumferentially spaced radial rib portions extending inwardly from the inner surface of said stacking rib portion.
3. A spin bonded composite container as defined in claim 1, wherein that part of said sealing fin portion which is spin bonded to said inner liner layer is of uniform thickness throughout its length.
4. A spin bonded composite container comprising:
(a) a vertically arranged cylindrical composite body member including a fibrous body wall layer, an inner thermoplastic synthetic plastic liner layer and an outer label layer;
(b) a synthetic plastic end closure member arranged adjacent one end of said body member, said end closure member including:
(1) a circular center panel portion closing the upper end of said body member;
(2) an inner annular sealing fin portion extending downwardly from said center panel portion adjacent said inner layer;
and (3) an outer annular chime portion extending downwardly from said center panel portion adjacent said outer layer; and (c) spin-bond means securing said sealing fin portion to said inner liner layer.
5. A spin bonded composite container as defined in claim 4, herein that part of said fin portion which is spin bonded to said inner liner layer is of uniform thickness throughout its entire length.
CA000435606A 1981-07-30 1983-08-29 Composite container having spin bonded ends Expired CA1171369A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000435606A CA1171369A (en) 1981-07-30 1983-08-29 Composite container having spin bonded ends

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US288,344 1981-07-30
US06/288,344 US4353761A (en) 1981-07-30 1981-07-30 Method for spin bonding ends for composite containers
CA000393203A CA1169371A (en) 1981-07-30 1981-12-24 Method and apparatus for spin bonding ends for composite containers
CA000435606A CA1171369A (en) 1981-07-30 1983-08-29 Composite container having spin bonded ends

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CA000393203A Division CA1169371A (en) 1981-07-30 1981-12-24 Method and apparatus for spin bonding ends for composite containers

Publications (1)

Publication Number Publication Date
CA1171369A true CA1171369A (en) 1984-07-24

Family

ID=27167185

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000435606A Expired CA1171369A (en) 1981-07-30 1983-08-29 Composite container having spin bonded ends

Country Status (1)

Country Link
CA (1) CA1171369A (en)

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