вход по аккаунту


код для вставки
June 10, 1947.
Filed Dec. '7, 1944
2 Sheets-Sheet 1
m www.
June 10, 1947.
E. _c. UHLIG
2,422,148 ‘
Filed Dec. 7, 1944
2 Sheets-Sheet 2
w MN
Patented June 10, 1947
Edwin C. Uhlig, Greenwood,
‘I., assignor ‘to
United ‘States Rubber Company, New 'York,
N. Y., a corporation of New'Jersey _
Application December 7, 1944,.Serial Nor-567,031.
7 Claims. (Cl.‘-1‘8-__-—56‘)
This invention relates to an improved method
of making battery separators formed of micro
present method ,proi/ides .a solution to ‘this. dini
porous vulcanized hard rubber or other micro~
It .is.,possih1e .to produce embossed microporous
separators, by placing a sheet of. heat-softenabie
microporous material between the cooperating
porous plastic composition,
Thin porous separators made of non-conducting 5.
material with sufficient mechanical strength for
platens of a‘heated embossing mold and; slowly
convenient handling‘areplaced between the posi
closing the mold to heat and emboss the Sheet,
tive and negative plates inv storage ‘battery cells
and then .0001 the mold below the softening ‘tem
where they serve to prevent metallic conduction
perature of; the sheet ‘before, opening the mold,
between the plates of opposite polarity. These
but if the temperature of the mold-hastobe raisedv
separators should be made as thin and-as porous
and loweredv for each separator ‘turned. out the
as other conditions will permit so that they will
production of such separators will be slow and
offer -a minimum electrical resistance when im
mersed in storage battery electrolyte, but the
pores-should be small enough'to‘prevent “treeing”
wherein-conductive particles that build up on the -
face of;a plate extend through-the separator from
one‘ plate to .the other to form a short circuit.
The presentiinverltion overcomes this difficulty
,andprovidesa simple‘practicaljmethod‘for quickly
reducing the temperature of the embossed‘ ‘sheet
belowlthatoftthe moldzwhilc it'isinthe embossing
Many ‘battery separators used heretofore have
This is accomplished‘ by wetting the micro
been formed of woqdor microporous vulcanized 20 lloiious sheet, With water, inthe case of vulcanized
hard rubber having spaced ribs of greater thick
hard rubber, and then inserting the wet sheet in
ness than the =?at'web portions of the separator
the heated embossing mold andclo-sing the “mold
lying ‘between the ribs. Since such ribs ‘were
to .embqssithe sheet, then vwhile the mold is closed
thicker than the 'web portionsv of the separator,
the temperature, oftheembossed'sheet is quickly
the increased thickness of the rib offered addi 25 lowered .by ‘forcing. air under ‘pressure through
tional ‘electrical resistance when the separator
apertures in ‘the mold and through the sheetrto
was immersed in ‘storage battery electrolyte.
thereby evaporate the water Contained in the
These separators may be made of microporous
sheet so thatlthis evaporation will serve'to reduce
vulcanizedvhard rubber or heat-softenablepl'astic
the temperature, ,of the sheet sufficiently to (set
30 the same in ‘the embossed condition. Themo'ld
In orderto make the embossed separators here
may then be openedand the sheet Will retain ao
in contemplated it is necessary to distend or dis
ourately the con?guration. imparted’ thereto. by
tort those portions of the'sheetiwhere the ribs are
the molding operation. ltwmaybe desirableihow
to be‘formed. Thishas-to be done carefully, par
ever ,tj0..o0ntinue the air lblastlior a short "preiod
ticularly if the sheet "to be embossed is a micro 35 after theimoldiis openedgtoifurther cool, thesepa.
porous-sheet of vulcanized :hard rubber, :to pre~
vent crackingthesheet in the vicinityof the ribs
during the embossing operation,
rator ‘and also to .aid in ejecting the embossed
separator from .‘the mold. i-ln ‘this manner the.
necessityorraising and‘lowering the .tempeliatilre.
In order lto'emboss-a sheet of microporous vul
of the‘, embossing ._mold each time a separator ‘is
canized hard rubber or plastic composition as 40 made is .avoided and theoneration of embossing
separators .may be ‘carried ‘out at. ihieh speed
herein contemplated, it is necessaryto heat the
.When hard rubber. or. _ other plastic materials
sheet until it'is softened ‘but not fused and then
herein contemplated areheated. while being sub
subject it to the embossing pressure. After the
sheet has been embossed- it should be quickly 45 jected, to‘ aconstant appliedload, .a temperature
is {reached at which. suchmaterial‘ beginsto soften
cooled to- a point below its softening temperature.
andlits ability '.to.__resist defamation under stress
This-‘preferably‘should be'done-before it is relieved
decreasesorapidly with :further rise .in- tempera
from-the embossing pressure, because if the em
ture. ' lI‘his isoiteningunder such further risein
bossing pressure is relieved whilethe sheet is still
is usually referred, to, as the “yield
in a soft condition it will not retain the sharp 50
temperature” and
‘be .so referred to. ‘herein,
contourimpartedto it by the embossing operation.
The need .Of loweringthe temperature of the em
bossedsheetbeiore relieving the embossing pres
sure presented a serious di?iculty in the way of
rapid .productionof embossedseparators, and the
In other words, =When~snQh materials. are heated
a temperature is ?rst reached at. .whichthemate
rial vtends to .lose. its. rigidity _ and _, permits. slight
bending under such-(load, the temperature -at
which, this occurs .is called -.the, ‘.‘softening tem
“softening point,” and it is easily
by employing the treatment disclosed in’
perature” or the
‘determined by using an A. S. T. M. test. As the
temperature increases further the material be
comes much softer and its ability to resist de
formation under stress decreases rapidly. This
temperature above the “softening poin fiat which 7
:the material ‘is su?iciently softened to‘ yield
the Baty and Meyer Patent No. 2,329,322. Such
separators in accordance with the’ present method
position indicated by IS in Fig. 3 of the drawing,
a sheet when vulcanized and ready to be em-r
bossed should have a thickness somewhere near
.027”, and should be su?iciently non-brittle to
handle well without breaking and to be embossed
in a manner now torbe described.
Before such a microporous vulcanized hard
quickly without rupturing is theabove mentioned,
rubber sheet is introduced into an embossing
“yielding temperature.” Hard rubber has a grad
press, such as shown in Fig. 3 of the drawing it
ual softening point and yield temperature ex- '
should be soaked in hot water and heated to a
‘tending over a wide temperature range,:whereas ‘
‘ .temperature of approximately. 200° F. It may
some of the other materials used to form battery
then be introduced in the embossing mold to the
may have 'a narrow temperature range.
ready to be dropped down upon. the lower em
wide range for hard rubber permits the operation 15 bossing platen. l6 having the embossing ribs 11,
of the embossing mold at relatively high tempera
which ribs are adapted to cooperate with the cor
ature to speed up the embossing operation, pro- '
respondingly disposed grooves l8 formed in the
vided the temperature of the embossed sheet is
‘ lowered below the yield temperature before the
upper platen I9. The lower platen I6 is rigidly
‘ embossing pressure is relieved.
The various features of the present method will
be more fully understood when read in connec
adapted to receive heating steam supplied by the
bossing separators in accordance with the present
. I
In the‘ drawings:
l the present invention.
’ '
30 of the yield temperature and should be heated
further before being subjected to the full em
bossing pressure. Therefore the press used is
preferably so constructed that it will close
Fig. 2 is a section taken on the line 2—~2 of
Although, the sheet [5 is wet and hot when ity
been transferred promptly to this press from a.
hot water bath, it is probably near the lower limit
Fig.1 is a plan view of a ?nished embossed
‘ battery separator constructed in accordance with
?exible pipes 22 and 23.
is introduced into the embossing pressrhaving
platenv I9 is similarly secured to an upper heat
ing unit 2i, These units may be heated electri
cally or by steam, and are shown'as hollow and’
tion with the accompanying drawings illustrating
one good practical formof mechanism for em;
secured-to a lower heating unit 20 and the upper
Fig. 1.
Fig. 43 is a side elevation with parts in section
of an hydraulically operated embossing press
against the sheet [5 under comparatively light
pressure, and then this pressure is increased as
' . adapted to produce theseparator shown in Fig. 1. 35
the temperature of the sheet I5 is elevated by its
Fig. 4 on a larger scale is a vertical sectional ‘
contact [with the heated platens l6 and I9.
This slow. complete closing of the embossing
3, the section being taken on line 4-4 of Fig. 5;
press is secured in the construction shown by
Fig. 5 is a top-plan view of the lower embossing 40 providing a main frame consisting of the up
rights 24 the upper ends of which are rigidly
secured to the head plate 25' which carries the
The method of the present invention may be
central block 26 to which isrigidly secured the
employed to produce microporous battery sepa
view through the lower embossing platen of Fig.
plate 21 adapted yieldingly to support the upper
rators ‘formed of hard rubber or other heat soft 45 heating unit 2| and 'upper platen l9. To this end
enable plastic material. The method will be de-'
bolts 28 are provided’ extending downwardly
scribedrin detail'ras employed‘to embo’ss micro-‘
through holes in the plate 21 and having thread;
porous sheets of vulcanized hard rubber and then‘
ed engagement withside portions of the heating
other heat softenable plasticmaterials which
unit 2!, whereby the heating unit is suspended
may be used in practicing the invention will bev » from the‘ plate 21 in spaced relation thereto but
described. _
may be forced upwardly into abutting relation
.The ribs formed upon‘ the embossed battery‘
with the lower face of the plate 21 upon ‘com
separator ‘herein contemplated serve to increase;
the stiffness of. the separator and to space the
same from the positive plate. These ribs may be
given various sizes and shapes and in the con-i '
struction shown the separator H3 is provided with
vertical rows of short ribs ll. provided through
out the major portion of the separator. These
rows of ribs, it will be. noted, terminate short of
the'upper and lower ends of the separator to. 60
provide marginal edge portions adjacent each
end of theseparator which are free from ribs, as
this construction lessensthe tendency of the sep
arator to crack at its ends. It will also be noted
pression of the coiled springs 29.
The lower platen l6 and heating unit 20 are
adapted to be hydraulically raised and lowered
and to this end there is provided the hydraulic '
cylinder 30, the lower» portionof which (not
shown) is rigidly secured to the lower ends of the '
uprights 2t. 'Within the hydraulic cylinder 30 is
slidably mounted the usual ram or piston 3|, the
upper end of which is secured to the'lower heat
ing unit 20. The lower platen I6 secured to this
unit has the upwardly ‘projecting aligning pins
32 adapted to enter correspondingly shaped holes
that the separator I0 is provided near each side 65 33 in the upper platen to insure accurate align
ment of the platens when the press is‘closed.
edge with the double ribs l2 having the looped
ribbedportions 13 extending laterally therefrom.
Between the upper and lower platens are con?ned’
Since the ribs H are made non-continuous'the
flat spaces 14 between the adjacent ends of such
The relative strength of the coiled springs '34
and 29 should be such thatwhen the ram 3|v is
elevated by the introduction of a liquid under
ribs. will lessen the tendency of ‘the embossed
separator?to spread laterally under. pressure ex
the coiled springs 34.
pressure within the cylinder 30} the lower platen
It will move upwardly until the sheet 15 resting
upon thelribs _I1‘will be moved upwardly into
ber of which‘ the separator shown in Fig. 1 of the
drawing is formed is preferably made micro-' 75 contact with the lower face of the platen l9,‘
erted against a face thereof.
The microporous sheet of vulcanized hard rub-V
whereupon” the'rupperiplaten' will > rise and com- 7
sure'to only-slightly- embossethisrlsheetiwhile-it is:
press "the-springs 29:‘- During/this upward‘travel'v
of theeuppersplatens |9~the temperature of the»
sheets l'5‘will be increased/by vits contact-with the
hot-platens and'the- embossing pressure upon this
sheet" will‘ be gradually increased. When’ the
forced ‘ upwardly: into-abutting relation with the‘
heatingunit/Z‘I ‘ abuts" against the plate?!“ the
sure-lof-abbut 80= pounds'per square inch maybe
sheet H‘r-will‘be subjected to the full embossing
being- fu-r-ther' heated by: its‘ contact" with» the:
platens l?ilan'dii l9”.g When-the- upper platen is
plate’ 21’ th‘esh-eett l5‘will‘be subjected to the full
embossing pressure, whereupon'eair' under! ‘prese I
forced“ through; < the 'iem'bossed sheet 1 l5 by mane
pressureof the hydraulic ram. The press may
ual-ly operating ‘avalve; not=shown, but adapted
then-'be'openedias soon as the temperature of the 10' to supply, air‘ to ‘the; ?exible pipes 40?, 40-} This
embossed separatoris reduced below the soften
ing~point,> so that the separator will not‘ flow
when the‘ press‘is opened and lose‘ the sharpness
of the‘ design impartedthereto by the embossing
stronga-?ow of? air‘ throughliall- portions of the»
perature so that the press will ‘quickly ‘heat - the
the platens‘to thesheet'l5-durin'g the early-stages
wet- sheet l5‘will quickly evaporate the» water
which it carries and>~by1~such evaporationrcool»?
the- sheet' 15;? whereupon‘ the“ press may- be;
15 promptly opened-landiithe ?nishedembossed'fsheet'
In order- to speed-‘:up production it is ‘desirable
I 51 removed ‘therefrom;
to'ma-intain-‘the platens l6 and l9‘at a tempera‘
It is highly importantfth‘at theisheeti l5-Ybe-wet
ture- well above the‘ lower limit of the yield tem
since» this- causes-aouicki transferpf heat from,
sheet‘ I 51su?i'ciently to cause the same to take the‘ 20 off'thesembossing‘operation, and also effects the"
full" pressure of-theapress without cracking, but
desired" coolin-g- just‘ described by‘ evaporating
as'just pointed out-the-embossing pressure on the
when a blast: of-'- air is *forced through- ' the sheet;
sheet IS-should not'be relieved as long as the
Air *alone' in'the- absence-*oflmoisture' in the: sheet '
temperature of this‘sheetlis well above the lower
i5¥~will noticool- the» sheet appreciably since'th'ise
limit of the yield temperature.
25 air will‘ bev heated by itsvpassage through‘the
Therefore inorder to produce embossed sepa
small apertures 35 in the hotrplatensz- The vari
rators rapidly‘ under the condition just men-7
ous steps-‘justldescribedJoan be carried out'in ?ve
tioned, the‘primary feature of the present inven
seconds or less from the time the‘ sheet 15: is
tion resides‘ in the step for quickly cooling the
?rst placed‘ in the moldiu-ntil the ?nished em;
embossed sheet- l51below the temperature of the 30 bossed '~ separator is“ removed therefrom.
embossing moldwhile such sheet is subjected'to
As above stated the embossed separator may be»
the-embossing pressure. This is accomplished by
formed of microporous vulcanized ‘hard ‘rubberior'
providing a large-number of vminute apertures
other heat softenableeplasticsr The following'is
such as drill holes 35¥inboth platens so that air
a list of heat‘softenable organic plastic materials
under strong'pressure‘ may be forced upwardly 35 that may be'used'in making'b'attery separators in“
throng-lithe lower'platen' Hiv and downwardly
accordance ‘with the: present ‘method.
throughlthe upper platen‘ I94 and through the
1. Vulcanized:hardvrubber; (natural rubber) 1
embo-ssedsheet l5; sov as'to vaporize rapidly the
2'. Vulcanized lhard rubber‘ (Buna S; Buna/Nl
water present in this sheet and utilize the cooling
3. 'Pla-stz'cized or‘ 1zon<rpZasticizad;—-plastics
effect of'suchr rapid evaporation 'to cool the em
(a)v Polystyrenes). (Poly?bre, Lustron; Styron,
bossedsheet I 57’to‘ a point below its yield tem
perature, whereupon the press may be opened
‘ #18: Styramic,v Styramic ' HT; .Cerex)
( b») vPo'lyacrylates @(Lucite, polymethyl-meth
and’ the finished embossed sheet removed there
(Q) ~ Polyvinylidenes; (Geon, Saran)
The construction whereby-compressed air is 45
(d) Polyvinylsl (Polyvinyl Chloride; Vinyl
suppliedtothe various apertures'35 of the lower
platenrl? is well shown in Figs. 4 and 5 of the
(e) Pclyami-des , (nylon) »
drawing, whereinit will be seen that‘ the lower
face-or-back of‘the platen l6~has formed trans
The plasticized or non-plastiriized-plastics are
versely'thereof‘near'the mid-section a relatively 50
preferably ?berized and 'collectedjin a batt ormat
wide channel 36~and*has leading therefrom‘ at
and then sintered-at .‘such pressureand tempera
right ~ angles‘ thereto the numerous "smaller chan
ture asrto. form a microporous..sheet having. a.
nels 31, The small apertures 35~are supplied with
porositygreater than. 40% and-the other physical
compressed air from the-channels 31. Air under
properties above described-as necessary; for the‘
pressureis suppliedto the main channel 36- by the
battery separator herein contemplated. ,The
port" 38‘ leading" from the drill hole 39 having
porosity of such . a. sheet. can be.‘ controlled .by; the;
secured thereto a-?exible air-supply pipe 40. A
?lament‘diameter or angular disposition of the.
gasket 4! lying between the adjacent faces of the
?laments in thesheet‘and pressure and heat used
platen- IB- and heatingun-it 20 prevents air sup
plied under pressure to the channels 36 and 31 60 to,unite. them..- A' microporous. sheet of . these~
plasticsv may. also be..formed by. sintering... small
from escaping in any direction except through
the small apertures35l- A construction such as
just described is also associated with the upper
platen- l9_ and serves to supply compressed air
to-its apertures 35
The. operation involved in carrying. out the
method "of the present invention may be brie?y
particles thereof .funderproper conditions.
If ‘the. plasticmaterial Jused has .a~..-higher, yield.
temperature-than 212? Ethenit may be desirable.
to use a wettingaliquid having.- a. higher boiling;
point than water, in. this .case. glycerolor. .biutyl
alcoholiibbutanol) may be. used. Suchliquid
should v'b'oil'at a temperature not‘muc'h' above the
described as follows: A microporous sheet of
yield temperature of the plastic separator sheet.
vulcanized hard rubber is removed from ‘a tank
As a result of the present invention the em
of hot water maintained at about 200° F. and 70 bossing platens l6 and I9 may be maintained at
placed in the position indicated by I5 in Fig. 3
a temperature near the upper limits of the yield
of the drawing, whereupon the hydraulic cylinder
temperature of the separator material, so as to
30 is supplied with operating liquid under pres
soften the sheet I 5 quickly and thereby speed
sure so as to force upwardly the ram 3| and close
the mold against the sheet l5 under enough pres
up the embossing operation, and by employing
75 the cooling operation secured by forcing air
through the wet sheet was temperature can, be ‘ before substantially all of its contained liquid is»
drivenbff, while 'undergthis hotv embossing pres-_,.
quickly lowered suf?ciently to permit the open,»
sure reducing the temperature of the embossed
ing of the press without losingthe accuracy ofv
, theembossed contour imparted to the sheet.
‘ This permits the embossing operation to be car-e
‘ ried out at high speed.
sheet to set the embossed design by forcing air
:' therethrough to volatilize theliquidlwith cooling
effect, and relieving theembossing pressure While
the temperature of the sheet isso reduced,
5. The method of producing an embossed-Ink‘,
crcporous battery separator, which comprises the
1.'The method of producing an embossed mi
of forming a microporous sheet ,ofiheat
croporous batteryrseparator, which comprises the 10 vsteps
softenable organic plastic composition, wetting
steps of forming a microporous sheet of vulcan- I
Having 'thus described my, invention, what I
claim- and desire ,to protect by Letters Patent is:
ized hard rubber; Wetting the sheet with water
and heating it while Wet, then subjecting this, hot ‘
wet sheet to a su?iciently high temperature and
embossing pressure to render the sheet soft and
emboss it quickly before evaporation of substan
tially all the water present occurs, and While
said sheet with a liquid that is- a non-solvent for 7
and is inert to the sheet and which boils at av
temperature equal to or, slightly above the em
bossing temperature, subjecting the sheet to a’
hot‘ embossing pressure in a press to emboss the
sheet before substantially all of its contained liq
uid-is driven off, while under this hot emboss
ing pressure reducing the temperature of the em-,
bossed‘sheet to set the embossed design by fore-
under such hot embossing‘pressure reducing the
temperature of the embossed sheet to render it
stiffer and set the embossed design by forcing
air'therethrough to evaporatevthe containedwa
ing air through the press and sheet to volatilize
ter. with cooling effect, then relieving the em-‘
bossing pressure while the temperature of the
the liquid with cooling effect upon the sheet,_and»
sheet is so reduced and opening the mold so that
perature of the sheet is so reduced.
relieving the embossing pressure while the tem
does not exceed ?ve seconds.
croporous battery separator, which ‘comprises the
steps of forming‘a microporous sheet of Vulcan
iZed hard ‘rubber; wetting'thezsheet with water
and heating it while Wet, then subjecting this hot
wet sheet to a suf?ciently‘high temperature and
2. The method of producing an embossed mi
croporous battery separator, which comprises the .
steps of forming amicorporous sheet of Vulcan
ized hard rubber; heating said sheet in the pres
ence of water, then subjecting this hot wet sheet
to embossingpressure between dies heated to a
suf?cientlylhigh temperatureto render the sheet
soft enough to be embossed without fracture of
the surface of the sheet and before, evaporation
of substantially all the water present in the sheet
occurs, and while under such hot embossing prese
6. The method of producing an embossed int-
the entire time the sheet remains in the mold
embossing pressure to render it soft and emboss
it ‘before; evaporation of substantially, all the
water present occurs, and then quickly reducing
the temperature of“ the sheet by forcing air
through the, sheet both before and. after it is re
lieved from the embossing pressure sothat the
resulting evaporation of the Water will lower the
temperature of the sheet to set its embossed de
sure reducing the temperature of the embossed
sheet to render it‘stiifer and set the embossed,
design by forcing air therethrough to evaporate 40; , 7. The methedof: producing an embossedmi
croporousbattery separator, which comprises the
the contained water with cooling effect, and then
relieving the embossing pressure of the dies while
steps of forming a microporous sheet of vulcan
the temperature of the sheet is‘ so reduced.
3. The method of producing an embossed mi
water, placing the wet hot sheet in an embossing,
ized hard rubber,v wetting said sheet withv hot?
press that is heated sufiicientlyto soften the
rubber quickly and closing the press to soften
croporous battery separator, which comprises the
steps of forming amicroporous sheet of vulcan
ized hard rubber; Wetting the sheet and placing
and emboss the sheet before complete evapora-ll
tion of the water present occurs, and’ while the
said sheet while in a Water-soaked condition in a
mold that is sufficiently hot to soften the sheet
to the point ‘where it can be embossed before most
of its water‘ is driven off,embossing the sheet in‘
said mold, and [while under the hot embossing
pressure reducing the temperature of the em
press is closed quickly reducing the temperature
50, of the sheet’ byforcing air through and over the
sheet, so that the. resulting evaporation of the
water in- the sheet will lower its temperature to
setithe sheet, and then opening the press toremove the sheet so that the entire time the sheet
remainslin the press does not exceed ?ve seconds.
bossed sheet to set the embossed design byforc;
ing air therethrough to evaporate the contained
water withjcooling effect, and relieving the em-,
bossing pressure while‘ the temperature of the
sheet is so reduced.
4. The method of'producing an embossed mi
'The following references’are of record in the
croporous battery separator, which comprises the 60 ?le of thispatent;
steps of 'forming a microporous sheet of heat;
softenable organic plastic composition, wetting
said sheet with a liquid that is a non-solvent for
and is inertto the sheet and which boils at a
temperatureyequal to or slightly above the ernev
bossing temperature, subjecting the sheet‘to a
hot embossing pressure so as to emboss the sheet
7 Date '5
Kyle ____________ __'J11l1ef15, 1934
'Osborne __________ __ Sept. 9, 1890
Osborne ______ __,___' Nov; _18, 1890
Без категории
Размер файла
847 Кб
Пожаловаться на содержимое документа