CA1114428A

CA1114428A - Foam dispensing nozzle and method

Info

Publication number: CA1114428A
Application number: CA316,888A
Authority: CA
Inventors: Azard A. Khan
Original assignee: Imperial Oil Ltd
Current assignee: Imperial Oil Ltd
Priority date: 1978-11-27
Filing date: 1978-11-27
Publication date: 1981-12-15
Also published as: DK504179A; JPS5577538A; NO793833L

Abstract

FOAM DISPENSING NOZZLE AND METHOD

ABSTRACT OF THE DISCLOSURE

A nozzle for preparing laminates of a foamable polymeric material and a substrate, said nozzle being sta-tionary over a moving substrate and consisting of a housing having a plurality of tubular members extending therefrom to deliver foamable material substantially across the width of the substrate transversely to the machine direction of the substrate.

Description

1 BACKGROUND OF T~l~ INV~NTION

2 The present invention relates to improved delivery

3 or nozzle m~ans for deliverin~ plastic foam material onto a

4 moving substrat~ or platen, for example, the ejection of a phenolic foam material onto the pliaten for the manufacture 6 o thermal insulation board.
7 In the preparation of foam materials, there is 8 usually a mixing o componen~s immediately prior to their use, 9 For examplej in the case of isocyanates, polyurethanes, polyols and other components may be mixed in a mixing head adjacen~
11 to the laydown nozzle, since the compvnents react in a rela-12 tively short time, which makes imperative a rapid laydown 13 before the reactive components can polymerize to a solid in 14 or around the mixer and nozzle. Hence, it is desirable and commercially expedient to place the mixed material onto the 16 substrate as quickly as possible~ The same considerations 17 exist for the phenolic foam where volatile liquids may be in-1~ corporated into the formulation for foaming~ for example U.S~
19 Pat. No;'s 3~694,387; 3g779J956 and 3~953~645 each describe phenolic resins which can be employed in the m~nufacture of 21 heat-insula~ing board.
~22 Thus, when dealing with such materials, rapid form-23 ulations and extrusion are essential. In the case of rigid 24 fOamS9 the mixing or creaming and laydown must occur before the plastic is crosslinkedJ in order to obtain the desired 26 foam. There are a number of devices which achieve ~his result.
2~ ~ Generally~ the mixing head is a tubular housing with various 28 ~ internal arrangements of mixing or shearing baffles, wherein 29~ ~the foam ing~edients enter generally at one end or along the , : , ~ 30 mixing head~ are intimately mixed, and are dispersed ~hrough .

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4Zi5 1 a nozzle (opening~ at the other end. One such mixing device 2 is described in commonly owned U.S. Patenl; 4,032,115. A nozzle 3 will generally have one opening, however, as in U~S. 43032,115, 4 there may be plurality of openings.
In practice, the mixing head and nozzle are mounted 6 to a traversing means whereby it is moved ~ransversely across 7 the path of ~he platen or substrate~ which is moving pas~ the 8 nozzle, thereby deposi~ing a ribbon of foam material in a zig 9 zag pat~ern onto the substrate. ~n plastic foaming processes, one normally essential requirement is to obtain an even dis-11 tribukion of density througho~t the product. This contributes 12 to consistent product quality within its own structure, thus 13 allowing the amoun~ of materials in the product and hence the 14 corresponding raw material cost to be minimized.
lS With the conventional traversing head it is often 16 difficult to achieve an even distribution. This results from 17 the change of direction of the traversing head at each extre-18 mity of its transverse travel path, and more particularly from 19 the alternately overlapping ribbons of foaming mixture, laid down by the traversing head not being able to uniformly cover 21 the available area of ~he substrate. These overlapping ribbon 2Z sites are places where high energy reactions occur which in 23 ~urn occasionally lead to the formation of horizontal shear ; 24 lines ~esulting in a weakened foam product. The line speed of conventisnal sys~ems is limited due to the ex~remely hi~h 26 traversi~g speeds necessary for uniform laydown coverage.
~27 It is a feature of the present invention tha~ the 28 t:r~aversing nozzle has been eliminated, thereby providing a 29 more uniorm and economic product. It is a particular advan-tage of the present invention that foamed plastic material 31~ la~inate board having low density variation is produced.

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4;2i~3 Another advantage is the reduction in mechanical wear in the board making apparatus by elimination of the traversing noz~le.
Another feature of the present invention is the adjustabili~y o~ the pattern of foam material deposited on the moving sub strate to compensate for the ~agaries of foaming characteristics at different points across the substrate. Another advantage is the elimination of the ribbon overlapping in ~he horizontal plane. These and other features and advantages will be ap-parent ~rom the ~ollowing descriptions, Thus specifically the present invention relates to a stationary, foam material laydown nozzle haviny a housing, means on the housin~ for securing it to a stationary source of foam material, and a plurality of tubular members secured to the housing to extend from it in an array suitable for the re~uired laydown of foam material, the tubular members communi-cating with the interior of the housing so that oam material can flow from the source and through the housing and tubular members for laydown of the foam material from the free ends of the tubular membersO

The invention also relates to a method of preparing a laminate of a foamed polymeric material and a substrate comprising suspending a stationary foam material l~ydown nozzle over a moving substrate, said nozzle having means for delivering a foamable polymeric material over substantially the entire width of said moving substrate without movement of said nozzle, dlspensing~a foamable polymeric material through said means for directing, whereby said foamable polymeric material falls onto said moving substrate substantially across the width thereof, and allowing said foamable polymeric material to foam .
on~said substrate.
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I)BSCRIPTION OP TIIB DRAWINGS
2 Fig. 1 is a partial cross sectional view of one 3 embodiment of the present invention attached to a mixing head.
4 Pig. 2 is an enlarged cross sectional view of one tubular member rom a nozzle ac:cording to the present 6 invention.
7 Fig. 3 is a perspective~ view of an alternative 8 embodiment o~ ~he present nozzle.
9 Fig. 4 is a perspective view o~ a second alterna-tive embodiment o the present nozxle.
11 Fig. S is a schematic representation in perspec-12 tive o~ the present nozzle in use, placing a continuous layer 13 of foam material on a moving substrate.

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1 5t MUARY 1' I l l c Il~VENTlON
2 Briefly, the present invention is a stationary 3 ~oam material laydown nozzle having a housing and a plurality 4 of elongated tubular members arrayed outwardly there~rom.
S The nozzle may be adapted to fit onto and be employed in com-6 bination with a foam ma~erial mixing head. The ~ubular mem-7 bers communicate with the mixing head or other foam ma~erial 8 source and provide ~he conduits ~hererom ~or the foam material.
9 Preferably the tubular members are arrayed along a center line oE the nozzle~ whereby they will lie transversely 11 across the path o~ tra~el of the substrate in use. The length 12 o~ the ~ubular members is preferably adjusted to provide that 13 the entire width of the moving substrate is covered with foam 14 material rom the stationary nozzle.
The tubular members are flexible to some degree 16 and allow adjustment of the position of the ensuing streams 17 of mixed foam materials which form on the moving substrate.
18 Thus, by selective adjustment of the tubular members, an even 19 dispersal of the mixed ma~erials may be achieved across the width of the substrate.
21 It has been found that maintaining all of the tub-; 22 ular members at the same length and diameter is a convenien~
23 and simple method of obtaining similar ~low volumes through 24 each. It may, however, be desirable to vary the length and diameter of the tubular members to obtain the desired foam 26 ~ material configuration on the moving substrate. Similarly, 27 in some embodiments a dispersed array of tubular members may 28 be employed to obtain the desired foam material flow and con-~29 fig~u~atlon. The array of tubular members may be adjusted to ~: :
accoun~ ~or the many Yagaries o~ ~he foaming ar~ and to . .

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1 advantageously employ the ~eed characterization of the par~ic-2 ular mixing head employed.
3 Another aspect of the present inven~ion is a met-4 hod of preparing a laminate of a foamed polymeric material and a substrate which comprises suspending a stationary foarn 6 material laydown nozzle over a rnoving substrate, said nozzle 7 having means to deliver a ~oamable polymeric material over 8 substantially the entire width of said movin~ substrate with-9 out movement of said nozzle, dispersing a oamable polymeric material through said means to deliver,whereby the ~oamable 11 polymeric material falls onto the moving substrate, substan-12 tially across the width thereof and allowing the ~oamable 13 material to foam. Preferably, the tubular members are arrayed 14 in a substantially straight line transverse to the direction of movement (machine direction) of the substrate. Preferably 16 the means for delivering the foam material over the wid~h of 17 the substrate comprises the elongated tubular members as des-18 cribed above.
19 In addition to the phenolic resins and polyurethanes discussed above many polymeric materials are produced as oams 21 or are foamable, including polymers and copolymers o~ ethylene, 22 propylene, vinyl acetate~ butene~ isobutene, butadiene; epoxy 23 resin, silicon resin, s~yrene-butadiene copolymer, butadiene-24 styrene-acrylonitrile copolymer and the like. The substrate 25 may be any material to which the foamed polymer will adhere 26 to form the laminate, for example, paper, cloth, sheekrock, 27 polymer ~ilms9 glass, fiberglass, wood, and me~al tsteel, al-28 uminum) and ~he like.

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1 DETAILED DESCRIPTION OlZ THE - ;
2 INVENTION AND PREF~RRED EMBODIMENTS
3 Fig. 1 shows one embodiment of the present nozzle 4 which comprises housing 9 through which extend a plurality of tubular members 14. In this embodiment, there are eleven 6 - tubular members arranged along a central plane through the 7 housing 9, 8 Nozzle 5 is shown attached to the terminlls of th~
9 particular mixhead disclosed in commonly owned U.S. Pat. No.
4~03Z,115 (corresponding to Canadian application, Serial No.
11 28~,362, filed June 13, 1977) which 12 describe~ a mixing head which forms no part 13 of this invention except that the nozzle shown is particularly 14 adapted lnternally to cooperate with the mixing head components of said patent apparatus. The no~le is attached by threaded 16 bolts ~not shown) spaced about the annular flange 13 and ex-17 tend through or into annular flange 7 o ~he mixing head 11.
18 A suitable ring 12 is situated between the front end of the 19 mixing head and the present nozzle.
The front end o the mixing head 11 adjacent to ;~ 21 the connection wlth nozzle 9 is illustrated. It is sufficient 22 for the purposes of the present invention ~o note that the ~23 foam ingredients enter the mixing head and travel there through 24 to the nozzle and out through tubular members 14. At its front end, the rotary impeller means 10 includes a toothed nut 15.
26; This toothed nut 15 is, threaded into the opening at the front ~Z7~ end of ~he impeller means 10 and also formed with a central 28; rearwardly dlrected recess, which receives the ~ront end of 29~ ~ the drive shaft means 8 which rotates the impeller9 thereby , ~ 30 ~ mlxing~and forcing the foam materials through ~he mixing head i~ :

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1 and nozzle 5. Nut 15 is formed at its front outer peripheral 2 region with a plurality of radially extending slits 6 which 3 slits 6 define, between themselvles~ the teeth of nut lS.
4 Between the front end of the impeller 10 and the nut lS there S is located a sealing ring 16, which has its periphery tapered 6 as illustrated in ~ig. 1, so as to form a suitable transition 7 region from the mixing head to the dispensing nozzle~
8 To accommodate ~his particular mixing head, the 9 inner sur~ace of the nozzle includes a radially extending groove ~(~! behind the tubular members 14. Thus, in this com-11 bination o~ prior art mixing head and ~he present nozzle, the 12 groove in cooperation, with the teeth of the nut lS provides 13 a scouring action which serves to prevent undesirable build-14 up of any solidified or gelled material at the front of the mixing head.
16 Fig. 2 shows an enlargement of the distal terminal 17 end of one tubula~ member 14. Each tubular member preerably 18 has the annularly bevelled surface 17 about the end thereof 19 to reduce the surface area thereby reducing polymer or gel build-up at that poin~.
21 - Since, the art of ~oaming polymeric materials is 22 more complex than it appears, it is highly desirable that the 23 tubular members be flexible or otherwise adjustable to obtain 24 the best extrusion pattern for a specific foam. Flexible tubing may be a material such as copper tubing or formed of 26~ interlocking rings9 as known in the art, for example.
27 ~ In FigsO 3 and 4 the tubular members are arranged 28 to recei~e ~oam material from other areas in the nozzle rather 29 ~ than ~u~ 8 cen~ral groove. For the scouring bene~its as des-cribod above, additional radial grooves ~not shown) or annular .
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1 grooves (not shown~ can be present on the internal surface 2 of nozzles 110 (~ig. 3) and 210 ~Figo 4) respectively. Alter-3 natively a space may be provided above the interior openings 4 of the tubular members by eliminating contact o ~he nut with S the internal nozzle. Quite obviously'for other mixing heads '6 than that disclosed in U.S. Pat. No. 4,032,115 other routine 7 mechanical adjustments will be required to match the present 8 no~zle to the mixing head or chamber.
9 In particular regard to the embodiment o~ Pig.
3 a configuration is shown where tubular members lll'lie on ll a central plane through the housing 110 with ~ubular members 12 112 and 113 being located on a plane perpendicular to the ~irst 13 plane. The terminal ends of the tubular members 111, 112 and 14 113 are shown arranged to lie on substantially straight lines ~ 15 (adjusted as noted above) to deliver a continuous film of foam ; 16 material onto the moving substrate 17 The embodiment of Fig. 4 employs tubular members 18 212 extending from the periphery of housing 210 and a central ,~
19 tubular member 211, again having all of the ends of the tubu lar members substantially in a straight line or adjusted in ~21 an appropriate configuration to produce the bes~ or desired 22 foamed product.
23 In addi~ion to the pa~tern of the foam material 24~ placed on the moving substrate9 consideration mus~ be gi~en 25 ~ to ~aria~ions in foaming characteristics at different points 26 ~ in the foam mass, e.g., the different conditions ~xisting along ; : : ~ ::
27 She edge of the substrate and in the oaming mass in the mid-28~: ~dle;thereof. Hence~ al~hough with some foam materials, and 29 ; ~in some foam equipment, i~ may be desirable to have the same 30 ~ or subs~antially ~he same flow rate through each tubular member, ~ ~ ~f'4~2 ~

1 in some combinations of materials and/or equipment, it will 2 be desirable to have diferent 1OW rates. This can be easily 3 achie~ed by adjusting the dimensions of the tubular members 4 to obtain the desired rate of foam material flow.
Fig. 5 shows the schematic operations of the pre-6 sent nozzle o the embodiment of Fig. 1. A nozzle 20 having 7 tubula~ members 21 is a~tached to mixing head 23~ arranfged 8 in such a pattern that the streams of oaming material 22 are 9 evenly distributed across the substrate 24, which is moving in the direction of the arrow in the ~igure. The foaming ma-11 terial 25 is shown on substrate 24. The nozzle 20 is fixedly 12 mounted and may be attached directly to the mixing head or 13 in some embodiments the mixing head may be situated at a more 14 ~ distant location and is connected to the nozzle through a conduit.
16 In the configuration shown in Fig. 5 ~he nozzle f 17 20 has a generally conical cross-section with the tubular mem-18 bers 21 extending outwardly along an arc on the cone surface l9 in the machine direction. In this embodiment, also, each tub-ular member is the same length~ The dispensed foam material .1 ' . . .
21 falls on the substrate in the pattern generally shown in Fig.
-~ 22 S.
23 ~ A s~ecific run using a nozzle as depicted in Fig.
~i 24 1 with the nozzle fixedly mounted as shown in Pig~ 5 was carried ZS~ ~ at a~line speed o~ 20 feet per minute with a substrate o~ single - 26~ faced co~ugated board, out to produce a 1 1/2 inch thick 27~ ~ foamed phenolic resin board having a standard dev;ation in `~;28 ~; density o~ abou~ 2.4% based on mean board weight.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A stationary, foam material laydown nozzle, for depositing a foamed polymeric material upon a longitudinally moving substrate, the nozzle having a housing, means on the housing for securing it to a stationary source of foam material, and a plurality of tubular members secured to the housing to extend from it in an array capable of producing laydown of foam material substantially across the width of the substrate, each tubular member communi-cating with the interior of the housing so that foam material can flow from the source and through the housing and tubular members for laydown of the foam material from the free ends of the tubular members.

2. The nozzle of claim 1 wherein the stationary source is a foam material mixing head.

3. The nozzle of claim 1 wherein at least one of the tubular members is flexible.

4, The nozzle of any one of claims 1 or 2 wherein all of the tubular members are flexible.

5, The nozzle of any one of claims 1, 2 or 3 wherein the tubular members are arrayed along a center line of said housing.

6. The nozzle of any one of claims 1, 2 or 3 wherein each of said tubular members is of substantially the same length and diameter, whereby similar foam material flow volumes are obtained through each member.

7. The nozzle of any one of claims 1, 2 or 3 wherein the terminal end of each tubular member is bevelled to a fine edge.

8. The nozzle of any one of claims 1, 2 or 3 wherein said housing has a conical configuration and said elongated tubular members are arranged on an arc on the surface of said housing,

9. A method of preparing a laminate of a foamed polymeric material and a substrate comprising:
suspending a stationary foam material laydown nozzle over a longi-tudinally moving substrate, said nozzle having means for delivering a foamable polymeric material over substantially the entire width of said moving sub-strate without movement of said nozzle, dispensing a foamable polymeric material through said means for delivering, whereby said foamable polymeric material falls onto said moving substrate substantially across the width thereof, and allowing said foamable polymeric material to foam on said substrate.

10. The method of preparing a laminate of a foamed polymeric material and a substrate according to claim 9 wherein said means for delivering a foam-able polymeric material comprises a housing having a plurality of elongated tubular members.

11. The method of preparing a laminate of a foamed polymeric material and a substrate according to claim 10 wherein said tubular members are arrayed in a substantially straight line transverse to the direction of movement of said substrate.