CA1129613A

CA1129613A - Apparatus for the preparation of hollow plastic articles

Info

Publication number: CA1129613A
Application number: CA328,841A
Authority: CA
Inventors: Emery I. Valyi
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-06-01
Filing date: 1979-05-31
Publication date: 1982-08-17
Also published as: JPS6316251B2; FR2427192A1; GB2022007B; GB2022007A; GB2103531B; SE7904836L; GB2103531A; AU510966B2; BE876642A; AU4463579A; FR2427192B1; JPS54157172A; DE2954187A1; DE2922195A1; IT7949260A0

Abstract

ABSTRACT OF THE DISCLOSURE

Apparatus for the preparation of hollow plastic articles wherein a more rapid operating cycle is obtained with less effect upon the temperature of the parison. The apparatus includes a first core, means for providing a parison thereon, a temperature controlled first mold engageable with said first core and parison, means for separating the first core from the first mold and parison contained therein, a second core in spaced relationship to the first core, means for transferring the parison to the second core, a blow mold in spaced relationship to said first mold for fully expanding the parison and means for transferring the second core and parison to the blow mold, wherein the blow mold is stationary and the second core with parison thereon is brought into alignment with the blow mold and is inserted therein.

Description

:1~29~t3 i BACKGR~UND OF THE INVENTION

This invention relates to the art of blow molding from a parison of articles of organic plastic material suscept~ble to the improvement of their properti~s by orientation and has for its principal objects the provislon of an apparatus which is characterized by a more rapid operating cycle with less effect upon the temperature of the parison, carrying out the steps of parison production, stretch orien~ation and circumferential orientation in a single uninterrupted, yet completely controlled sequence, and the provision of improved, oriented hollow articles.
The art teaches various methods and apparatus for obtaining blow molded articles of organic plastic material from a parison, such as in U.S. Patent 3,349,155 and Re~ 27,104.
i Generally, these methods are characterized by forming a parison in a parison mold on a blow core, placing said formed parison and blow core into a blow mold and expanding said parison in the blow mold by means of fluid pressure.
~ hile the blow molding operation tends to i~.part ) orientation to the article, such orientation is predominantly circumferential, i.e., not bi-axial. Also, the degree of such orientation is difficult to control. It is therefore -1- ' .

~ 1 2 9~1 ~ Y~260 di~ficult to obtain the ad~antageous properties in the article that bi-axial orientation is capa~le of proyiding, It is known th~t the control o~ ~r~entatlon de~ends la~gel~
upçn the control of the temperature of the parison ~ust prlor to orlentation. ~t ls found that such te~perature control is best obtained by enclosing the article prior to the orienting step in heating ~eans that impart temperatures, preferably by contact ~ith the corresponding surfaces of the parison, to the regions of the parison correspondlng to the degree o~
de~ormation that is lntended for such regions.
Ho~ever, art devices that o~tain the desirable hi-a~lal orientation are often cumbersome and slo~ and incon~enient to operate. Also, production rates with such devices are ~ar ~rom optimum.
SUMMARY OF THE INYENTION
In accordance ~ith the present invention~ an apparatus is provided for khe prep~rat~on o~ hollow articles ~aintainlng su~stantially consistent temperature control of the articles prior to orientation and/or prior to final expansion, ~hile also ohtaining an i~pro~ed, conrolled inJectlon ~low ~oldin~
or st~etc~ ~low molding sequence ~th a rapid operating cycle w~ich ~as less effect upon the temperature o~ the parison.
The apparatus of the present invention also obtains numerous other significant ad~antages which will he-more readily apparent ~rom the ensuing specification.
The apparatus o~ the present in~ention co~prises; a reciprocahle first core, preferahly ~ially reclprocable~
and a temperature controlled ~irst mold, preferably laterally reciproca~le; ~eans ~or providing a parison on said ~irst core;

means includlng said ~irst core to place said parison in said

2 9~1 3 ~-260 ~lrst mold; means for separating said parison fr~m ~aid first core while retaining said parison in said first mold to ad~ust the temperature thereof; a second csre and a second mold in spaced relationship to said ~irst core and first ~old, respectively, preferably in lateral spaced relationship, wherein said second core is reciprocable, pre~erably a~ially and laterally reciprocable, and wherein said second mold is stationary; means for transferring said parison to said second core and second mold; and means to expand said parison on sald second core in said second mold to provide a finished article.
Preferably, the apparatus includes an article removal plug for removing the ~inished article in integral, spaced relationship to said second core, preferably in lateral spaced relationship, so that when the second core engages the parison in the first mold, the removal plug engages the finished article in the second mold.
In accordance with the apparatus of the present invention, the parison walls may be caused to est;ablish intimate surface contact with the walls o~ the first moldg such as by forcing said parison ln the first mold to conf`orm to the shape of the first mold~ such as by expansion, The parison shape may be chosen so as to permit the insertion there1n of the second core into intimate surface contact with the inside of the parison.
The parison is therefore in full surface contact wlth the first mold for adjust~ent o~ the temperature ~f t~e parison~ an~
possibly also in full surface contact with the second core~
The temperatures o~ the first mold, of-the second core, or of both~ may be controlled to provide optimum conditions in the parlson for orientation thereof.

-3-1129613 Y~260 Alternatively, the parison may be stripped ~rom the first core into the first ~old without substantially deforming the parlson~ in whlch case the shape Or the ~irst ~old is substantially the same as that of the parison to insure.adequate surface contact between the two. At times, the parison may be placed within a heated cavity that does not correspond to the shape of the parison, such heated cavity taking the place of the ~irst mold. This heated cavity is the equivalent of the first mold in the present conte~t and it will be included within the term "first mold" throughout the present specification.
In view o~ the plural cores and molds used in the present invention and the high degree of temperature control which can be e~er.cised over the parison, the present invention readily obtains a multi-axially oriented art'Lcle by axially stretching the temperature adjusted parison at a predetermined rate in the second mold by means of the second core and by e~panding the parison to form the ~inished art-Lcle. ~urthermore, the ~ovement parameters of the components of the present apparatu~
prov~de a highly efficient and smooth operation.
If it is desired to produce a multi-layered parison.and a multi-layered ~inal article, the first core may be provided with-a layer o~ one plastic and a subsequent layer may then be pressure ~olded therearound in accordance with.my U.S. Patent Nos. 3,349,155~ 3,717~544 and 3,719,735, It should be understood, therefore, that where the general description that follows refers simply to parisons, the method and apparatus o~
the present invention are applicable to ~ulti-layered as well as sin~le-layered par~sons.

112g613 Y_260 Thus, a multl-axially oriented article may be readily obtained in accordance with the apparatus o~ the present inyention by-providlng means ~or axially stretching the temperature ad~usted parison at a predetermined rate and by the e~pansion of the same, such as by an axially reciprocable portion of the second core that is actuated by means capable of ad~usting the speed of reciprocation.
It can be seen that the apparatus of the present in~ention ef~iciently and conveniently obtains uniform temperature control 0 of the parison so that the resultant article is characterized by highly improved properties~ while obtaining a high production rate. It is known that orientation substantially improves the significant properties of plastics, as clarity, impact resistance, strength, resistance~to permeation, etc. Among the plastics that can be so improved are polystyrene, polyYinyl chloride, polyolefins, as polyethylene and polypropylene, polyesters, polycarbonate 8, polyamides~ acrylics, fluorocarbon resins, acrylonitrile, and ~etbacrylonitrile polymers. The improved temperature control of the present ~0 invenkion enables one to obtain improved properties and controlled multi-a~ial orientation in a simple and e~peditious manner.
Accordingly, it is a principal object of the present invention to provide an apparatus for the preparation of hollow articles from moldable organic plastic material which enables accurate temperature control and a rapid and e~peditious operating cycle.
It is a ~urther ob~ect of the present in~ention to eonveniently and expeditiously provide improved artlcles whlch are multi-axlally oriented under condltions of close contrvl of temperature and deformation rate.
It is a still further object of the present inven-tion to provide an apparatus as aforesaid which provides products possessing reproducibly uniform properties due to orien-tation.
In accordance with a particular em~odiment of the invention, there is provided an apparatus for forming objects of moldable organic plastic material which comprises: a reciprocable first core and a temperature controlled first mold, means for providing a parison on said first core, means .including said first core to place said parison in said first mold, means associated with said first core for separating said parison from said first core while retaining said parison in said first mold to adjust the temperature thereof; a second core and a second mold in spaced-relationship to said first core and first mold, respectively, wherein said second core is reciprocable into and out of engagement with said second mold and wherein said second mold is stationaryi means for trans~erring said parison to said second core and second mold; and means to expand said parison on said second core in said second mold to provide a finished article.

.-,--, ,:., ~j -1~9~13 Other objects and advantages of the present invention will be apparent to those skilled in the art from the description which follows with reference to the accompany-ing drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an elevation, partly in section, illus-trating the apparatus of the present invention, Figure lA shows a core modification in the apparatus of Figure 1.
Figures 2 and 3 are views similar to Figure 1 with additional portions in phantom showing a sequence of operations according to an embodiment of the present invention.
Figure 4 is a partial vle,w similar to Figures 1-3 showing a modification of the apparatus of the present invention, Figure 5 is a schematic elevation similar to Figure 1 showing a plurality of cores and molds.
Figures 5A and 5B are schematic top views o~ the second cores showing a variation of the embodiment of Figure 5, Figure 6 is a schematic view showing a plurality of first cores in a variation of the apparatus of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in more detail, Figures 1, 2 and 3 illustrate an apparatus in accordance with one embodiment of the present invention, In this embodiment, the parison is provided by an injection molding process' however, the invention is not limited thereto and includes other known molding processes that are capable of producing parisons such - 6a -., 11~9~13 V~26Q

as compression moldingg castlng9 extrusion with or without secondary operation, and the like. Fig~re 1 depicts a parison die 1~ having ou~er walls 11 whlch may be separable, depending upon the shape of the pari~on and whlch are adapted to form the - outer surface of the parison9 and havlng an end wall 12 shaped to form the end wall of the parlson. The par~son die 10 may be temperature controlled, such as by heating or cooling elements lOa contained therein which are connected to appropriate heat - transfer sources (not shown) whereby such temperature control may be arranged in se~eral zones to obtain different temperatures in different regions of the parison The end wall 12 of the parison die has an injection opening 13 registering w-l~t~ an injection n~zzle 14 through ~hich the organic plastic material is inJected into the parison die.
The parison die 10 is shown as split for.con~enience in opening to release the ~ormed parison; however, it should be understood that the in~ention is not limited th~ereto, as one piece dies suitably designed for release o~ the parison are encompas~ed herein.
As indicated hereinabove, the plastic~.conte~plated in accordance wlth the present invention are the molda~le organic plastic materials and preferably those whose properties are impro~ed by orientation, such as the pol~o1e~ns-J polyethylene, polypropylene and copolymers thereof, polyvinyl chloride, polystyrene and other s.ty~en~c resins, acrylonltrile, methacrylvnitrile, poly~inylidene chloride, polycarbonates, polyesters, polyamides~ fluorocarbon resins, etc.
The formation of the parison in accordance with the embodiment il-lustrated in Figures 1, 2 and 3 ~akes place a~ter a ~irst core 15 ~preferably a blow core) illustrated in 11~9613 Y-260 Figure 1, and set ~orth in phantom in ~lgures 2~3, and die 10 are brought into engagement by suitable mechanical ~eans such as the motive means shown schematically in ~igure l. In the embodiment shown in Figures 1, 2 and 3, core 15 is axlally reciprocable in.the.direction of the arrow into and o~t of engage~ent with die 10. Upon completion of inJection through nozzle 14, a parison 16g having substantlally the config~ration represented in ~igure 2, is formed.
Side wall 17 and an end 18 of core 15, walls 11 and 12 of parison die 10, and the neck mol.d 20 constitute a die cavity in which the parison is for~ed. Core 15 may ~e temperature controlled in one or more zones, such as by internal heat exchange clrcuits known in the art contained therein, which are connected to an appropriate heat tranæfer or power source (not shown). Core 15 is carried by platen 19. This assem~ly further includes a neck mold 20 in which the neck of the parison is formed and ~hich remains en~aged with the parison while the latter remains on blow core 15 after disengagement from the parison die, ~hich neck mold ~ay be independently temperature controlled. The neck mold may possess threads 21 ~or definlng a threaded opening in the final molded o~ect. The neck mold 20 may be split and opened lnto two portions by suitable mechanical means such as the motive means shown schematically in ~igure 1, to release the parison, or, if the configuration o~ the neck permits, may be of one piece construction and, thus, separable from the parlson as a unit.
During separation of the parison die 10 and the core 15, the parison 1~ is sufficiently retained thereon by means Or neck-mold 20, or by other means, such as an undercut, 1~
necessary. Upon separation, the parison assumes the position ll~g~

deplcted in Figure 1 and shown in ph~ntom ln ~igu~e 3, First mold 2?, which is a conditloning, i.e., te~pering mold and may be a pre-forming mold, and core 15 are ~rought into align~ent so as to ~u~tapose ~irst mold 22 and parison 16, lllustrated, as noted earlier in phan~ in Flg~re 3. As sho~n, ~irst mold 22 is laterally reciprocable by suita~le mechan~cal means, such as the motive means shown sch~atically in Figure 1, with the flrst mold moving in the direction of the arrow into and out of alignment with core 15. ~old 22 iS .
temperature controlled, frequently in multiple zones which may be dlsposed along the length thereor, as by heating or cooling e.le~ents 22a which are connected to appropriate heat transfer sources (not shown). It is possi~le, although not preferred, to align first mold 22 and parison 16 by lateral or circular reciprocation of core 15.
Referring to Figure 3, upon the alignment of first mold 22 and ~core 15 bearing parison 16, core 15 and parison 16 are then placed wlthin first ~old 22, ~or exa~ple, by the axial reGiprocation of core 15. Other ~eans of engaging parisons and molds may be used and are .~ell known, such as t~ose '.
disclosed:.in U.S. Patent Nos. 2,853~736 and 2,974~362. The parison is then released from first core 15 into first ~old 22~
as by stripping it a~ially which may be facilitated, if desired, by partially expanding the par~son. The partial expansion is carried out by arranging for the mold cavity of mold 22 to be a small frackion of an inch larger than the parison and ~y applying fluid pressure thrsugh channel 27 on the inside of the parison thereby e~panding the parison into conformance with the cav~ty ~f mold 22. Passage 27 is provided withln core 15 ~0 and may terminate at a valve-like, closeable portion Or the ;

_g_ 11~36 ~ 3 Y~2~Q

core well known in the art. Separation of the parison from core 15 may then be facilitated by air-pressure stripping o~
the parison from the core,-with remsval of the core ir~m the parison leaving the parison in mold 22. It should be noted that such expans1on is not always necessary, but is often helpful as in the e~ample shown. If des~re~, an exit channel (not shown~ may be provided on ~old 22 to permit the remoYal of air from the mold cavity as the parison enters facilitating the esta~lishment of contact of the parison with the mold walls The temperature of first mold 22 is controlled by heating or cooling means 22a connected to appropriate heat trans~er sources (not shown)~ or by electric heaters, to opt~mize the parison temperature for subsequent operations in a manner to be described below. Naturally any suitable heatln~ or cooling means may be used in any of the heating or cooling coils described herein, such as a passage containing heat transfer fluld maintained at a suitable temperature, electric -resistance heaters or radiant heat sources.
Fi~ure 3 illustrates the pressure ~olded parison 16 as conformed to the shape of the mold ca~ity in firs~ mold 22, for e~ample, by the exertion of fluid pressure, with the partially expanded parison labeled 29. At tl~es the shape o~ partially expanded parison 29 may be made such that a second core, e.g., stretch-blow core 30, may bè inserted lnto substantially complete surface contact therein, as shown in ~igure 2, permitting heat exchange throughout, by contact o~ the second core and the parison. In such an instance, the said shape should exhibit no undercuts or reverse curves on the inside surfaceg fDr e~ample, due to an outward taper oYer its inside surface.
Ho~ever, the parison shape does not always permit this, for --10-- , ~2bo 1~29613 . example, in some cases of long, narrow-necked parisons, in which cases lt may be necessary to forego contact heating the inside of the parisons After c~mpletion of the transfer of the pari~on lnto first mold 22 9 that mold and ~irst~core 15 are separated ~ by moving the first core plu5 flrst neck mold axially in the direction of the arrow, usually accompanied by the application of air pressure at the inside o~ the parison by ~eans of the first core, and the parison 29 thus transferred is retained in 0 first ~old 22. Core 15 and neck mold 20 are then returned to the starting posltion as illustrated in ~igure-l, and first ~old.22 containing the pari~on 29 which may be partially e~panded, is shifted laterally into the position illustrated in Figures 1 and 2.
Parlson 29, which is retained within first ~old 22, is thereby trans~erred into alignment with a second core 30 which is carried by platen 31 and which ma~ be proYided w~th .temperature cont~ol means, and which may ha~e an e~ternal con~ig~ration shaped to conform to the internal con~iguration of the parison 2~. WheneYer axial stretching of the parison is desired, core 30 will include a stretch and ~lo~ assembly which comprises a mandrel extension 32 which is reciprocable as-~ndicated by the arro~.in Figure.l to axially e~tend t~e parlson 29. An actuating means i3 shown which co~prises a push rod 34 which engages extension 32, and which is connected to a.piston 35 housed within a cylinder 36.which may, for example, be responsiYe to hydraulic pressure e~erted by a pump, not shown. B~ controlling the ~low of fluid lnto cylinder 36, the speed of piston 35 and therefore of the moYable portion of core 30 may be controlled to stretch the 11~9613 parison at the speed best suiked for the ke~perature of the pari~n. Such actuating ~eans i5 merely illustrati~e o~ one manner of operation, as other actuating means known in the art can be employed herein. If a highly oriented article is not desired, the a~ial extension operation may be dispensed with.
For the final forming sequence, the parison is separated from first mold 22 by retaining it at the neck reglon on core 30 and, at times, also on.a neck mold 37 ~hich operates in the s~me !
manner as neck ~old 20. In the absence of neck mold 37, one may o retain parison 29 on core 30 by close fit of core 30 within the i neck of the parison, or, as shown in Flgure lA~ by pro~idlng an .
expandable sleeve 30a made of an elastomer or the like at the neck region o~ core 30 arranged to grip the neck of the parison internally, ~hereby such a sleeYe may ~e oaused to e~pand by air pressure brought to it from the core, as through fluid passageway 38.
Core 30 i5 situated in spaced relationship to core 15, and ~irst mold 22 is situated in spaced relationship to second mold 23, to enable both cores to engage a respectiye ~old when core 15 is aligned with mold 22 a~ shown in Figure 3, This facil~t~tes the concurrent pursuit of hoth the temperi~ and final forming processes with separate parisonsO Further, and with regard to the trans~er of parison 29 to core 30, it should be noted that par~son die 10 is spaced rrom first mola 22, as , illustrated in ~igures 1 and 2, so that core 15 may engage with die 10 to form another parison while core ~0 engages with first mold 22 and also while a th~rd core 41 e~ects the fully expanded article 40. The ability to concurrently conduct the Yario-~s-operations o~ the process outlined herein comprises one of .the nota~le advanta~es o~ the invention. The s~multane~us Y~260 112961~ `

formatlon3 transfer, or final expanslon and finished article removal o~ a plurality o~ parts is en~isioned, as the apparatus illustrated ln the accompanylng figures can be further modified to provide additional intermediate molds and cores 9 such as mold 22 and core 30.
A fluid passageway 38 is provided and terminates at the end surface of that portion of the core 30 which does not moYe during the movement of extenslon 32. Fluid passagewày 38 also connects to a source of fluid under pressure, not shown.
Accordingly, fluid ~ay enter the space inside parison 2~ during final expansion, discussed hereinafter, once passageway 38 is opened by movement of the extension 32 and correspond~ngly of the mo~able portion of core 30. If the transfer of the parlson out of first mold 22 is to be facilitlated by gripping the parison from the inside as shown in Figure lA, elastic sleeve 3~ais pressurized from its inside surface ~y means of pressure air through secondary passageway 38a causing the sleeve to expand against the inner half of the parison neck.
In the instance ~here core 30 may be made to conform to the inner contour of parison 29, it can be seen that core 30 may be heated or cooled. Thus, the ~emperature of parison 29 may be ad~usted by heat exchange between both the inner and outer surfaces of parison 29 and the corresponding mold and -core surfacesO
The parison 29 s thereby rapidly and uniformly prepared for further processing, such as axial e~tension and f~nal e~pan~ion. This is a considerable advantage since it avoids the problem of parison cooling during a multi~step process.
Whenever core 30 may be made to conform to the shape of parison 29, the heat trans~er conditions may ~e further improyed ` 11~9~13 over the ones prevailin~ if only the outer surface of parison Z9 is in heat transfer relation with a corresponding mold element. Naturally, the conventional temperature regulators that are used to control the heating means of core 30 and mold 22 are able to do so individually, in several zones within the assembly, corresponding to the desired temperature profile.
In the interest of a rapid operating cycle, it is particularly advantageous to first rapidly alter the heat con-tent of parison 16 by heat exchange with core 15 and mold 10 to result in a heat content desired for subsequent operations, but almost always at the cost of an unequal distribution of temperature in said parison. This must be followed by sub-stantially equalizing the temperature distribution across the wall thickness of said parison by heat exchange with mold 22 and, whenever made to conform with the inner wall of the parison, with core 30, to avoid a layer-wise pattern of properties in the finished article corresponding to the known relationship between such properties and the deformation temperatures. This procedure is described in more detail in my U. S. Patent 4,116,606. ~hus, for example, one can form parison 16 by injection molding, rapidly cool ;`
said parison by heat exchange with core 15 and mold 10 which will result in a rapid cycle, but will also produce said unequal temperature distribution, ~ollowed by substan-tially equalizing the cross-sectional temperature distribu-tion of said parison, all in a controlled manner, to impose thereon the temperature profile desired for orientation.
Naturally, the parison rem~ins in mold 22 until the necessary desired temperature distribution adjustment is obtained.
Alternatively, in accordance with the present invention, a -7 `~ ~ - 14 -11296:13 ~; 26n pre-formed parison may be placed in mold 10, heated rapldly ln ~old 10 by heat e~change-~ith mold 10 and core 15, whlch is al~o apt to produce said ~nequal temperature distribution~ and further treated in-~old 22 by heat e~change ~ith ~old 22 and core 30 to substant~ally equalize the temperature dlstrl~ution of said parison. The foregoing provides the considerable advantages of enabling the attainment of a predetermined temperature profile Or the parlson resulting in optimu~
conditions for orientation without excessiYe dwell time in the molds. The parlson mold is freed for ~urther use ~hile the ~irst mold is completing the conditioning o~ the parison, resulting in an expeditious processing cycle.
Referring to Figure 2, the transfer of parison 29 to finishing mold 23 is conducted by core 30 whlch is in engagement with ~lrst mold 22 and parison 29. Core 30 ~ith parison 29 thereon is separated from flrst mold 22,- ~hich ~ay be split to release parison 29, by moYing core 30 a~ially by suitable mechanical means such as the motive means shown schematically in ~igure-l. Upon release, core 30 ~Ith parison 29 thereon returns to the posi~-lon lll~strated in Figure 1 and depicted in phantom in Figure 3.
In accordance with the apparatus of the present lnvention, the second mold 2-3 is ln lateral spaced relationship to said first mold 22, with the second mold being fi~ed. The ~i~ed or stationary position of the second mold represents a significant ad~antage o~ the apparatus of the present invention, It per~it~
the placement of the parison much more rapidly and hence with less er~ect upon its temperature~ Also, second mold 233 if it is a multi--impression mold (which is o~ten the case) ls apt to weigh several tons~ The movement Or such a mass ~ith great -15~

1 1 ~ g~ Y_260 speed requires elaborate, expensive and not altogether efficaclou~ means to control acceleration and deceleration of the ~vement; ~hereas9 the parison with the core assembly weighs but a ~ew pounds and may be mo~ed swiftly by s~mple means~ e.g., cushioned-end air cyllnders.
As can be seen in Figures 1 and 2, a third core or article removal plug 41 for removing the finished article is ln integral, lateral spaced relationshlp to second core 30, ~ith both the second and thlrd cores being carried on platen 31. Therefore, L0 when the second core engages parison 29 in second mold 22, the removal plug 41 engages the finished art~cle 40 in the second mold 23. As shown by the arrows, the second and third cores are ax1ally and laterally reclprocable so that the ~econd core transfers parison 29 from mold 22 to mold 23 ~y a combination of axial, lateral and axial movements. Simultaneously, third core 41 removes the finished article from mold 23, which may be split and separable to facilitate the extraction Or the ~inis~ed article, and transfers same to an e~ection station ~ located laierally of mold 23 (not shown) ~or remoYal of the ~inished article while core-30 engages mold 2~.
Core 30 carrying parison 29 is then recelYed in ~old 23;
with the te~perature of parison 29 having been ad~usted as described above. Parison 29 is usually axially extended to the bottom of mold 23 by the advancement o~ the movable portion of s mandrel 32 by ~eans of push rod 34 at a predetermined rate.
Thus, the present invention ~ay controllably stretch the parison longitudinally be~ore final blowing and thereby produce orientation in the axial direction as well as the orientation subsequently produced by blowing. It can be seen that the temperature of the parison preparatory to stretching and blowing ~129613 ~_260 may be properly and con~eniently controlled by the respect~Ye molds and core. -W~ile stretching occurs, pa~sageway 38 is kept open to pro~lde pressure equalization Or the inside of the parlson with the atmosphere to pre~ent collapse of ~he parison due to the vacuum created inslde It as its inside volume increases during stretching.
- After completion of axial ~xtenslon~ the parison-is fully e~panded to conform to the configuration o~ ~inishing, i.e,, second mold 23, to form the flnal:ob~ect ~O:which9 in the embod~ment illustrated herein,-is an open-ended container.
Naturally, a wide variety of shapes may be prepared as the commercially known shapes which ~ay be a bottle, a ~ar or a cup-shape. Full expansion is accomplished by supplying fluid under pressure through passageway 38 into the interlor of a~ially extended parison 29, or at times and at ~arious rates, into the interior of the parison ~h'Lle it ls being e~tended.
After full expansion is c~mpleted, second core 30 and second mold 23 containing final ob~ect 40 are separated as descri~ed Elereina~ove with reference to first core 15 and first mold 22. The second core is moved axially, laterally and ~ axially, ~hlch positions the second core in the ~irst mold 22 - and at the same time positlons removal core 41 in finished article 40 for removal-of same after the ~inished article has cooled-sufficiently for that purpose.
- In the embodiment illustrated herein, finlshing ~old 23 is longitudinally split into two sections la~eled 42 and 43, whlch may reclprocate in and out o~ communication by an actuating meansj not shown, such as ror ~xample a hydraulic cylinder.
~hus, sections 4? and 43 ma~--be parted an amount -suffic~ent to permit ~he rem~val of article 4~ ~y core 41 w~ic~ may be inserted 1~29613 Y-26a into the neck thereo~ with a tight flt. Prior to such opening of mold 23 and removal, fluid pressure may he applied through passageway 46 to continue the blowing process, i~ desired3 in cases requiring continued contact of article 4~ with second mold 23 for the purpose of extended coollng. Alternatively, passageway 46 may ~e utilized to continue to supply cooling air to the 1nside Or the finished art~cle, or to apply suction to -the inside of the finished article to aid in retaining same thereon.
Thus, it can be seen that the present invention improves the in~ection ~low molding process and carries out the steps of parison production, stretch orientation and circumferential orientation in a single unlnterrupted and co~pletely controlled sequence. The parison is in~ected or provided in a first station and is moved axially from the first station on a first core. The parison is then transferred by the first core into a first or tempering mold which i9 9hifted laterally into alignment with the flrst core for that purpose. The first mold is then shi~ted laterally ~ith the parison thereIn into a second station wherein a second core is inserted into the parison and the second core with parison thereon is ~oved axially away from the first mold. The second core with parison thereon is then shifted into alignment wlth the second mold and inserted therein for final processing inko a finished article, with the finlshed article being e~ected by a third or e~ection core.
The apparatus and process of the present invention is simple, convenient and progressive in nature. The parison moves fr~m the--~n~ection ~old-to first-core; from ~irst core to tempering mold; from tempering mold to a second core which may 112 9 6 .L 3 be a stretch-blow core; fr~m second core to finishing mold and out; or prefera~ly from flnlshing mold to a third eJection core and out. The ~aYement of components is quite s~mple and convenlent and e~peditious, with the large, ~u~ky ~lnish~ing mold being stationary.
The temperature ad~ustment of the parison afrorded by the present invention has been found to provide an oriented product ha~ing consistently good properties. The parison is in~ected into a comparatively cool mold and le~t there ~or a ~ery short time, long enough to remo~e the amount o~ heat from the parison that corresponds to the condition ~est su~ted ~or orientation.
The parison is then trans~erred into a tempering ~old ~hich imparts the opt~mum orientation temperature distribution to the given plastic artlcle, staying in that mold long enough to equalize the temperature across the ~all thickness o~ the parison whlch naturally arrives from the In~ection mold with a poor cross-sectional temperature prof'~le. After tempering, the parison, now having the right temperature pro~ile with good cross-sectional d~stri~ution, is transferred into a cool ~20 ~in~shing mold in which it is stretched at a-controlled rate and ~lown. The steps of in~ection plU5 dwell in the in~ectlon mold;
o~ tempering and o~ stretch-blo~ing with cooling overlap; and of article remoYal, occ~r at the same tl~e allowing ~or ef~lcient macbine utillzation. Also, the component ~ovements allow ~or smooth operation.
Naturall~, many ~ariations ~ay ~e ~ncluded, In~ected or blown necks may ~e ~ade. The stretch ~nction ~ay ~e ~mitted, ln which ca~e a Yery e~r~cient in~ection blo~ ~old~ng operation is provlded. Instead o~ tempering, the second station ~ay he ~sed as a ~irst hlo~ station and the thlrd station m~y ~e used -lg-11~9613 Y~260 as a second blow statlon in order to dl~de the cooling d~ell bet~een-the t~o. This may be deslra~le in the case of thick-walled articles~ In fact, additional cooling stat~ons may ~e added.
In one modification, the-parison ~ay be-~ormed earller at a time and location of its own and stored ~efore ~e~ng for~ed into the flnal artlcle. In addition to in~ection mold~ng, numerous methods are known that may be employed to provide thermoplastics in the shape o~ a parison~ such as tube e~trusion with welding of one open end, dipping, deposition, thermoforming and the like. Thus, the previously formed parison may be transported to and placed upon a first blow core which cooperates with a heating means to raise the te~perature of the parison suf~iciently to enable it to undergo de~ormation.
Secondary operations often need to be per~ormed upon the hollo~ article made in accordance wlth the present invention.
Among these is the application of a base cup to the articles ha~ing a domed bottom as is frequently the case ~lth ~ottles that haYe t~ withstand appreciable internal pressure, e,g., car~onated beverage bottles. These ~ase cups are ~sually plastic dish-like o~Jects ~ith a ~lat bottom, the-inside o~
the dish often bein~ glued to the conve~ ~otto~ of the bottle so as to render it capable of standing upon a ~iat sur~ace, These ~ase cups are usually applied in a special deYice to which ~ottles that haYe been previously made are rand~ly presented.
In accordance with the improvement illustrated by the modificatlon of ~lgure 4, it is posslble to dispense ~ith suc~
a separate de~ice and lnstead to integrate the ba~e cup applicator-lnto the apparatus itself. In accordance with the em~odi~ent oY ~i~ure 41 a ba~e cup applicator i5 proYided for 1 1 2 g~ 26n applying a ~ase cup to the hase o~ the finished article~ wlth the applicator being located ln lateral spaced relatlons~ip to the ~econd mold so that ~hen the second core and parison engage the second mold CFigure 3) the appllcator carrylng a ~ase cup engages the base of the finished article on the removal plug.
As shown ~n Figure 4, base cup applicator 50 ls carried ~y a suitable platen 51 ~hich may be movable in the directlon of the arrow by suita~le ~otive means. The applicator includes a sleeYe portion 52 and a bottom base cup carrier 53. In operation, carrier 53 is loaded ~ith a base eup 54 by conventional means, not shown. The ~ase cups ~ay ~e proYided wlth adhesive 55 at predetermlnedg spaced locatlons for adhering to the bottom of the finished article. The base cups carried by applicator 50 are then engaged with the base o~ the finished article 40 with sleeve 52 surroundin~ the finished article to keep same ~rom ~uckling outwards. Air pressure may ~e supplied inside the ~insihed article by passageway 46 in coxe 41.
Pressure is then applied-to carrier 53 ln the direction of the arro~ pressing c~p 54 firmly agalnst the base of the bottle 40.
Upon c~pletion o~ the requisite setting times for the adhesive 55, if used, the applicator is removed frQm the ~inlshed article 40 now equipped with a base cup 54, and the article is stripped from the plug 41.
It is well known that in in~ection molding it is desira~le to minimize the length over which molten plastic is ~ade to ~low and also to group individual cavlties ln in~ection multi_ cavity ~olds so as to minim~ze the platen space which helps accuracy in moldin~ due to the reduced hazard of deflectln~ the support structure-of--the mold under-the great forces of in~ection. As shown in the schematic diagrams of ~ig~res 5, ~1~961 3 Y.26n .

5A and 5B which utiliæe an apparat~s according to F~g~res 1, 2 and 3, an apparatus is provided includlng a pl~rallty of first cores in spaced relatlonshlp to each other carried by a c~mon carrying ~eans~ a plurality of first-molds ln spaced relationship to each other carr~ed ~y a c~m~on carrying means, a plurality of second cores in spaced relationship to each other carried by a common carrying means, and a plurality of second molds in spaced relationship to each other carried by a com~on carrying means, wherein a plurality of the fin~shed articles I are made simultaneou~ly. Naturally, the molds may be spllt for convenience of article or parison remoYal. As shD~n in Figure 5, the cavities 111 in multiple parison mold 110 are arranged in a row cooperating with ~irst cores carried on common carrying means or support plate 119. The parison die 110 cooperates with in~ectlon unit 114 through wh~ch ~olten plastlc is injected through channel 113 dist;ributed by runner 113a.
The spacin~ between cavities 111 corresponds to the d~mensions of the parisons. Accordingly, the spacing of the second cores 130 carried ~y common carrying ~ean~ or platen 131 must o correspond to t~at of the cavities 111 if the parisons made in cavitles 111 are to ~e transferred in the manner shown in Figures 1, 2 and 3. The parisons are then transferred thro~gh the processing cycle in a manner after Figures 1, 2 and 3 - utilizing a plurality of first molds 122 and a plurality of second molds 123.
Hollow art~cles to be made ~r~m parisons are frequently much larger than the parisons and hence cannot be accommodated with the s~me center spaclng as the parisons. F~r example, the parison for a large bottle may have a diameter of approximately 1-1~2 inches~ while the bottle ~de ~r~m the ~129~.3 ~-260 -j parison ~ay ~easure 4 inches ln d~eter. In accordance w~th the e~bod~ent of ~igures 5A and 5B, whlch represents a schematic top ~ew of the second cores-in two di~erent positlons, means are provlded ~or ~o~ing said second cores aw~y ~r~m and towards each other in a predetermined relationship. The apparatus accordlng to ~igures 5A and 5B acc~modates the larger center spacing of the finished article ~hile preserving the c~mpact arrangement ~n the parison ~old as in ~igure ~. Two ro~s 131' and 131" of second cores 130' are pro~ided to mate with two o correspond~ng rows or-parisons (not shown~. ~eans are provlded to spread the two rows-o~ second cores, such as spreader bars 150 connected to any suita~le motive means, in the direction of the I
arrows. Thus, once the parisons carried by second cores 130' complete the tempering cycle in the first molds Cthe position æhown in ~igure 5A~ and the parisons-are separated there~rom~
khe spreader bars 150 are ~oved to spread the second cores 130' to the center lines of the ~lnishing ca~tie~ of the second ~olds. ~to the po~Ition shown in ~igure 5B~, A~te~ stretching ¦
- and ~lo~ing in the second molds, the second cores are remo~ed ~o fro~ the hollow art~cles and ~oved toget-her aga~n to the center lines-of the ~lrst ~olds to resume the ne t c~cle. ¦
~igure 6-shows a ~rther impro~ement aimed at handl~ng parisons ~ade o~ plastics that require a prolonged t~mpering .
cycle pr~or to bi~axial orientation ~y stretching and blo~ing.
A~ong these plastics,.polyprop~lene being the ~ost prominent, I tempering cycles in terms of ~inutes are called for, ln contrast to t~mpering cycles measured in seconds that are .
needed in connection with other materials. The pxoblem in connect~on ~ith an apparatus ~or th~s type o~ ~aterlal is to IQ introduce an extended tempering cycle without at the ~e t~me . -23-11~9613 Y~260 prolonging the actual operating cycle o~ the de~lce and ~ithout constructlng extremely bulky and ine~icient heating-apparatus.
Figure 6 seh~atieally- show~ an apparatus ~hich acco~plishes the~oregOing ~y including a plurallty ~f ~irst ~olds ~oYahle ~nto positions spaced ~rom the cores ~o~ Extended ad~ustment of the t~perature of the parison, In the em~odiment s~own ln Figure 6, a multi-tier arrange~ent is pro~lded ~n the te~pering -station show~ng a plurallty of ~rst ~olds 222, In operatlon accord~ng to ~igures 1, 2 and 3, when a mold 222 ~lth the par~son reaches the tempering station it is side~hifted hy conventional motive means to neighboring position A. In a ne~t cycle, lt may ~e further slde-shlfted into an ad~oining posl~i~n A', and so on, whereby the nu~ber o~ such side positions will depend upon the actual tempering c~cle desired~
As ~llustrated in Fig~re 6, upon reach~ng position A', the tempering mold is moved to a lo~er tier, i.e., into pos~tion Bt', ~rom whence it is moved ~urther into posit~on B', and ~r~
there to posltion B, ~rom ~hich pos~tion tt is elevated into the original upper tier, i.e., into the ~osition at which ~old 222 had or~inally entered the tempering cycle, Positions A~ A', etc. and B, ~', etc. may of course be arranged at either s~de, or ~oth sides o~ the temperlng station. It can ~e readily seen that by means of this simple side-shift and eleYator dev~ce, the parisons may ~e given any e~tended te~pering des~red without impeding the overall operat~ng cycle of the ~aehine.
Thus, the ~ach~ne output ~-11 remain the sa~e regardless of the tempering dwell provided that a sufficient num~er o~ tempering ~olds are used. -Naturally, all ~ol~s in circulation ~ay ~e c~nne¢ted to a source ~f energy9 for example, in the case o~
electrlc heatlng, electric power may reach each mold over a ~ Y~260 - . ~
1129~13 slld~ng connector .cooperating ~lth suitable conventional bus bars, In accordance ~ith the embodiment of Figure 6~ the.parisons arri~ing ln the.~lrst o~ tempering mold are not remo~ed therefrom by the second cores, but prior thereto, the first ~old is side-s~ifted to giYe an e~tended tempering cycle ~hile keep~ng.the parisons under controlled temperature conditions.
The length of time for this d~ell will depend ~pon the number of molds that are in circulation. The remo~al o~ the temperPd par~son may occ~r at positlon B.
Instead of the preferred device for using a multipllcity o~ tempering molds as aboYe described, it is conceiva~le to move a ~ultipllcity of first molds along different paths, for example, in a circle, which may be ~e-rtical or horizontal~
However, care must be taken to keep t:he parisons in a vertical pos~tlon to a~oid their di.stortion and to keep the molds in contact with temperature control unlts~ .
In summary, in accordance with the embodiment of Figure 6, an apparatus is provided for form~ng obJects of moldable 2~ plastlc material requiring prolonged temperin~ cycles to obtain conditlons suitable for.orientation, said apparatus lncluding a multiplicity Or temper~ng molds for retaining parisons prior to .orientation, whereby the tempering molds recei~e an~ release .
the parisons seriatim and whereby the o~erall cycle of the apparatus is substantially unaf~ected by the number of the tempering molds. Preferably, the apparatus is of the type shown in Figures 1~ 2 and 3. .
As indicated hereinabove, in connection with the discussion ¦
of Figure 4, secondary operations can if desired be per~or~ed 3o at the eJe~tor station. One illustration of these secondary , ~. -1 ~2 g~ 1 3 Y~260 operatlons ls the attachment o~ a ba~e cup 54 to the finishedarticle 40 by means of a base cup applicator 50, Naturally, other ~econdary operations may readily be performed at the e~ector station as sho~n in my pre~lous ~.S. Patents 3j336,425 and 3~587,133, ~or e~ample, one ~ay flll the ~inished article while-said article ls confined by means oi the base cup applicator 50 or other suitable means to confine the walls of the finished artIcle ~hile said article is betng ~llled.. This procedure ~ill ena~le one to readily hot ~ill the finished 1~ article and, if desired, maintain the fllled article confined until cooled suf~iciently to handle~
This invention may be em~odied in other forms or carried out in other ways without depart~ng ~r~ the splrit or essential characteristlcs thereor. The present em~odiment is therefore to be con~idered as in all respects illustrattve and not restrictiYe, the scope of the lnvention being Indicated by the appended clai~s, and all changes which come ~lthln the meanin~ and range o~ equiYalency are.intended to ~e em~raced therein.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. An apparatus for forming objects of moldable organic plastic material which comprises: a reciprocable first core and a temperature controlled first mold, means for providing a parison on said first core; means including said first core to place said parison in said first mold; means associated with said first core for separating said parison from said first core while retaining said parison in said first mold to adjust the temperature thereof; a second core and a second mold in spaced relationship to said first core and first mold, respectively, wherein said second core is reciprocable into and out of engagement with said second mold and wherein said second mold is stationary; means for transferring said parison to said second core and second mold; and means to expand said parison on said second core in said second mold to provide a finished article.

2. An apparatus according to claim 1 wherein said first core is axially reciprocable, said first mold is laterally reciprocable and said second core is axially and laterally reciprocable.

3. An apparatus according to claim 2 wherein said first core is solely axially reciprocable and wherein said first mold is solely laterally reciprocable.

4. An apparatus according to claim 1 including an article removal plug for removing the finished article in integral, spaced relationship to said second core so that when said second core engages the parison in said first mold, the removal plug engages said finished article in said second mold.

5. An apparatus according to claim 1 including an expandable sleeve at the neck region of at least one of said cores arranged to grip the neck of the parison internally.

6. An apparatus according to claim 4 including a base cup applicator for applying a base cup to the base of the finished article, said applicator being in lateral spaced relationship to said second mold so that when said second core and parison engage the second mold, the applicator engages the base of the finished article on the removal plug.

7. An apparatus according to claim 6 wherein said applicator includes a sleeve portion which surrounds said finished article when the applicator engages the finished article.

8. An apparatus according to claim 1 including a plurality of first cores in spaced relationship to each other carried by a common carrying means, a plurality of first molds in spaced relationship to each other carried by a common carrying means, a plurality of second cores in spaced relationship to each other carried by a common carrying means, and a plurality of second molds in spaced relationship to each other carried by a common carrying means, wherein a plurality of said finished articles are made simultaneously.

9. An apparatus according to claim 8 wherein means are provided for moving said second cores away from and towards each other in a predetermined relationship.

10. An apparatus according to claim 1 including means for injection molding said parison on said first core,

11, An apparatus according to claim 1 wherein said means for transferring said parison from said first mold to said second mold includes said first core, and wherein said apparatus includes means to separate said parison from the first core and to conform said parison to the shape of the first mold,

12. An apparatus according to claim 1 including means engageable with said first core for molding on said first core.

13. An apparatus according to claim 1 wherein said second core is a blow core and fully expands the parison in said second mold.

14. An apparatus according to claim 1 including means for axially extending the parison in said second mold to provide a final article which is multi-axially oriented.

15. An apparatus according to claim 1 including a plurality of first molds movable into positions spaced from said cores for extended adjustment of the temperature of said parison.

16, An apparatus according to claim 1 including an ejector station for ejecting the finished article in lateral spaced relationship to said second mold, and means for per-forming secondary operations on said finished article at said ejector station.