CA1052968A - Embossed thermoplastic material - Google Patents
Embossed thermoplastic materialInfo
- Publication number
- CA1052968A CA1052968A CA219,314A CA219314A CA1052968A CA 1052968 A CA1052968 A CA 1052968A CA 219314 A CA219314 A CA 219314A CA 1052968 A CA1052968 A CA 1052968A
- Authority
- CA
- Canada
- Prior art keywords
- film
- embossed
- protuberances
- length
- mils
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
- B65D65/38—Packaging materials of special type or form
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/18—Thermoforming apparatus
- B29C51/20—Thermoforming apparatus having movable moulds or mould parts
- B29C51/22—Thermoforming apparatus having movable moulds or mould parts rotatable about an axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
- B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
- B29C59/022—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
- B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
- B29C35/045—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam using gas or flames
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
- B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
- B29C59/04—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Laminated Bodies (AREA)
Abstract
EMBOSSED THERMOPLASTIC MATERIAL
ABSTRACT OF THE DISCLOSURE
An embossed thermoplastic film characterized in that one surface of the film is provided with a plurality of rows of substantially truncated, parallelogram-shaped protuberances which extend perpendicular to both the longitudinal and the transverse axes of the film. The protuberances in one of the rows of protuberances aligned with one of the axes are offset from the protuberances in the next adjacent row of protuberances by about one-half the width of the length of the base of an individual protuberance. The embossed film has little or no tendency to curl when subjected to tension in the longitudinal or machine direction.
ABSTRACT OF THE DISCLOSURE
An embossed thermoplastic film characterized in that one surface of the film is provided with a plurality of rows of substantially truncated, parallelogram-shaped protuberances which extend perpendicular to both the longitudinal and the transverse axes of the film. The protuberances in one of the rows of protuberances aligned with one of the axes are offset from the protuberances in the next adjacent row of protuberances by about one-half the width of the length of the base of an individual protuberance. The embossed film has little or no tendency to curl when subjected to tension in the longitudinal or machine direction.
Description
-105'~968 Back~round of the Inve_tion Field of the Invention This invention relates to embossed thermoplastic materials, particularly to thin, flexible, embossed thermo-plastic films suitable for use in a variety of applications.
Description of the Prior Art Embossed plastic film or sheet material has come into widespread use in many fields. One particularly large-scale use of embossed thermoplastic sheet material is that of disposable -articles such as hospital pads and drapes, wearing apparel and disposable diapers. Embossed film is also finding increased use in the packaging field, for example, as bags and o~erwraps for articles such as clothing, etc., and for shopping bags. In order to fulfill the requirements established by a large number of end r~
I
, :
. .
i '' ' : ' : . . - .
iOS'~968 uses of embossed fllm, it i~ teslrable that the flln have little or no tendency to curl along its edges when run through fabricating machlnes, partlcularly those used for manufacture of disposable clothlng artlcles, e.g., tiapers. In some cases, it i8 important that the embos~ed thermopla~tlc fllm be very soft and flexlble and have the proper pattern and embos~ment depth in order to provide the desired "hand" or clothlike feel for the thermoplastic embossed material. Atditionally, for many uses it is de~ired that the embossed thermoplastic material have as low a surface gloss as posslble in order to ~imulate woven clothlike fabrlcs.
Further, embossed thermoplastic materials must meet the minimum physical requlrements necessary for the films to be handled in high speed, automatic, fabricating machinery, i.e., it should have suitable modulus, tensile strength and impact strength.
While embossed thermoplastic film has been commerically available for many years in a number of different patterns, e.g., hemispheres, rectangles, squares, diamonds, etc., presently avallable films are characterized in that the protuberances are allgned in evenly spaced rows wherein the protuberances are in alignment in adJ-cent rows. The valleys which eparate the rows of protuberances of prior art embossed films are contlnuous and extend from edge to ed8e in both directions--generally both parallel to the longltudinal axis ant transverse ax~s of the length of embossed film.
Embossed film having a truncated pyramid pattern wherein the valleys separating the pyramids are continuous over the full length and width of the film i8 shown in U.S. Patent 3,76~,940.
Examples of embossed film having a pattern of rounded top, rectangular base protuberances wherein the valleys extend perpen-ticular to the transverse and longltudlnal axes of the fllm i~ -hown ln U.S. Patent 3,484,835. Square patterned fll~ produced by embossing on a travelllng wlre whereln the valley~ extend p-rallol to the longitudlnal and transverse axes of tho fllm is
Description of the Prior Art Embossed plastic film or sheet material has come into widespread use in many fields. One particularly large-scale use of embossed thermoplastic sheet material is that of disposable -articles such as hospital pads and drapes, wearing apparel and disposable diapers. Embossed film is also finding increased use in the packaging field, for example, as bags and o~erwraps for articles such as clothing, etc., and for shopping bags. In order to fulfill the requirements established by a large number of end r~
I
, :
. .
i '' ' : ' : . . - .
iOS'~968 uses of embossed fllm, it i~ teslrable that the flln have little or no tendency to curl along its edges when run through fabricating machlnes, partlcularly those used for manufacture of disposable clothlng artlcles, e.g., tiapers. In some cases, it i8 important that the embos~ed thermopla~tlc fllm be very soft and flexlble and have the proper pattern and embos~ment depth in order to provide the desired "hand" or clothlike feel for the thermoplastic embossed material. Atditionally, for many uses it is de~ired that the embossed thermoplastic material have as low a surface gloss as posslble in order to ~imulate woven clothlike fabrlcs.
Further, embossed thermoplastic materials must meet the minimum physical requlrements necessary for the films to be handled in high speed, automatic, fabricating machinery, i.e., it should have suitable modulus, tensile strength and impact strength.
While embossed thermoplastic film has been commerically available for many years in a number of different patterns, e.g., hemispheres, rectangles, squares, diamonds, etc., presently avallable films are characterized in that the protuberances are allgned in evenly spaced rows wherein the protuberances are in alignment in adJ-cent rows. The valleys which eparate the rows of protuberances of prior art embossed films are contlnuous and extend from edge to ed8e in both directions--generally both parallel to the longltudinal axis ant transverse ax~s of the length of embossed film.
Embossed film having a truncated pyramid pattern wherein the valleys separating the pyramids are continuous over the full length and width of the film i8 shown in U.S. Patent 3,76~,940.
Examples of embossed film having a pattern of rounded top, rectangular base protuberances wherein the valleys extend perpen-ticular to the transverse and longltudlnal axes of the fllm i~ -hown ln U.S. Patent 3,484,835. Square patterned fll~ produced by embossing on a travelllng wlre whereln the valley~ extend p-rallol to the longitudlnal and transverse axes of tho fllm is
- 2 -t-p/t~
. .
~05'~968 ohown in U S Patent Re 23,glO ~ S Patent 3,137,746 dlsclo~es a film having a hexagonal~ raised pattern on ooe surface thereof .. . .
whlch 1~ subsequently oriented and slit between the embos~ments to produce a porous film The hexagons are lnltlally arranged 80 that contlnuous valleys exist on two opposite sides of the lndlvldual rows of protuberances Embossing patterns as shown in the foregoing patents produce an embossed film which i8 deficient in strength in one or more directions of the film by virtue of the fact t4at continuous valley6 separate one or more of the rows of aligned embossments ; When the film begins to tear along this line, slight effort is required to continue the tear from one site of the film to the , ~ : -other Atditionally, films having t-he foregoing pattern arrah~e-ments to not provide as much resistance to edge curl as is desired in modern embossed film which requires resistance to tension in the longitudinal or machine direction in order to be successf~lly utllized on high speet converting equlpment, l e , diaper-making ,`', machlnes. ,~
Thus, it can be seèn that the film embossing art is in neet of an embossed thermoplastic film which will provide a hish resistance to edge curl and which has a high resistance to tear in at least one of the longltudlnal or transverse dlrections o~
the film Summarv of the Invention i It 18 an ob~ect of the presont invention to provite an `~ mbossed thermopla~tic fllm havlng a high resistance to edge curl ~hen ~ub~ected to stress ln the longltudinal dlrectlon It i8 a further ob~ect of the present lnvontlon to provlde a thermoplastlc embossed film which has a hi8h re81~tanc-to toar along at lea~t one of the ~aJor axe~ of the fil~
It i~ a Jtlll further ob~ect of the present lnventlonto provlde a thermoplastlc embos~ed fll~ whlch ha~ a ~harp, well d-flned, ~mall embossed pattern thereon .
_ 3 _ V,,, O , .. . ...
It is another ob~ect of the present lnventlon to provlte a thermoplastlc embossed film whlch has deslrable "hand" and low gloss.
The thermoplastlc embossed film of the present lnventlon is characterlzed ln that one surface of the film is provldet wlth a plurallty of rows of substantlally truncated, parallelogram-shapet protuberances extenting substantially perpenticular to both of the axes of the fllm. The rows of protuberances which are aligned with one of the axes are separated by continuous valleys which extend from one free etge of the film to the other. The rows of protuberances which are alinged with the other of the axes are separated by a plurallty of short alignet valleys, each valley having a length substantially equal to the length of the base of one of the protuberances.
Brief Descrlptlon of the Drawing FIGURE 1 is a perspective view of an embosset thermo-plastic sheet of the present invention;
FIGURE 2 is an enlarget perspective view of the top or the male surface of the thermoplastlc embossed fllm of the present lnvention;
FIGURE 3 i8 a cross-sectional view of the film of FIGURE 2 along the line 3-3;
FIGURE 4 18 a cross-sectional view of the film of FIGURE 2 along the llne 4-4, ant FIGURE S i8 a schematic view of an apparatus for pro-ducing the embossed film of the present invention.
Description of the Preferret Embodiments - Referring noP to FIGURE 1, there i8 seen a thermoplastlc . mbossed sheet of film of the present invention deslgnated generally by the numeral 10, Phich has longltudlnally extending dges 11 and lla and transversely extendlng edges 12 and 12a.
; Sh- fllm has an upper surface designated by the nu~eral 13 and a lower surface desi~nated by the nu~eral 14.
d-p/ ~ ~
~OS'~968 The embos~ed fllm ~hown ln FIGURE 1 has been produced by feedlng a contlnuous length of fllm lnto the nlp of sn embo~sing roll along the machlne dlrectlon or longltudlnal dlrectlon a~
indicated by the arrow marked "MD" The transverse direction is marked by the arrow wlth the legend "TD"
As seen more clearly in FIGURE 2, the embosset fllm of thls inventlon is provided with a plurality of parallelogram-shaped protuberances designated generally by the nu~eral 15, all of which extend upwardly out of the plane of the film from its upper surface 13 The protuberances are pyramidal-shaped and more preferably truncated pyramidal-shaped As can be seen, the protuberance~ are arranged in longltudinally extent~ng or machlne direction rows 16 and transverse or cross direction rows 17 The - series of ad~acent, longitudinally extending rows of protuberances 16 are separated by continuously extending valleys or depression~
18 whlch extend from the upper edge 12 to the lower edge 12a over the entire length in the machine direction of the fil~ The rows 17 whlch extend ln the transverse direction or acro6s the width of the fllm 10 are defined by a serie~ of interrupted, short valleys 19 The short valleys 19 have a length which is equal to -~the width of the base "b" of the truncated parallelogr-ms a8 can be seen more clearly ln FIGURE 4 These short valleys 19 are produced and result from the novel pattern wherein the ad~acent protuberances of each row in the longitudinally extending dlrectlon and ln the transversely extending direction are offset from each --~
~- other by a width whlch is ~ub~tantlally equal to one-half of the ba-e "b" of each of the protuberances as seen ln PIGURE 2 ~8 seen more clearly in FIGURES 3 and 4, each protuber-nce 15 has a helght inticatet by the letter "h" The protubor-nces all extent upwardly out of the plane of the fll~ as ~een ~ore clearly ln FIGURES 3 and 4 The sldes 20 of the protuberanc-- ;
aro lncllned at an angle "alpha" to the plan- of the fllm Thl~
; ngle ~ay be from about 20 tegrees to about 75 degr-e~ The -- S --t-p/ ~
-~05Z968 protuberances generally may have a base width "b" of from about 4 mils to about 50 mils. The protuberances have a height "h" of from about 2 mils to about 20 mlls. In general, the embossed films of this invention are prepared from thermoplastic films having an initial thickness of from about 0.5 mils to about 10 mils.
The particular shape of the protuberances of the embossed film of the present invention is not ~ritical, i.e., they may be in various forms. They may be in the form of squares, diamonds, hemispheres, but generally are preferred to be parallelogram type protuberances. Additionally, in the most preferred form, the protuberances will have generally truncated or flat tops whether t they be pyramid, diamond or other shape~.
The embossed film of the present invention can be prepared from any suitable thermoplastic material, particularly .~
/ the homopolymers and copolymers of alpha-olefins having 2 or 4 carbon atoms, e.g.-, medium, low and high density polyethylene, .'J polypropylene, polybutene-l, and copolymers thereof with each ~ other and with other polymerizable comonomers. Also sultable are '~ 20 films made from polymerized and copolymerized vinyl monomers such as polyvinyl chloride, polyvinylidene chloride, polystyrene and other such type films. Other films that may be embossed include polyethylene terephthalate (Mylar*), polyvinyl acetate, Ionomer, polyvinyl alcohol, Nylon and other polyamides, cellulosics such ;
as cellulose acetate or butyrate, styrene-nitrile type copolymers and graft polymers. Additionally, embossed films may be made from multilayer films, for example, films such as polyethylene:Nylon, HDPE:LDPE:HDPE, LDPE:polyvinyl acetate:LDPE, LDPE:polypropylene: -LDPE, and others.
The embossed film of the present invention may be pre-pared by any suitable means by utilizing a preformed web of film and passing it between embossing rollers, or extruding molten * trademark dap/~
. ; ,.
-lOSZ968 thermoplastic from a slot die tirectly into the nips of a palr of embossing rollers. As seen in FIGURE 5, an unembos~ed fllm web 21, whlch may be preformet or extruted from a slot dle as de~crlbed above, i8 pa~sed into the nlp 22 of a palr of normally contactlng embossing rolls 23 and 24. If preformet film is u~ed, the film 18 heatet by any suitable heating means (not shown) to a suitable temperature for embossing prior to entering the nip of the emboss-ing rolls. One embossing roll, for example, roll 23, may be a .
hollow steel cylinder having the truncatet pyramit pattern described above engraved on its surface to provide an upwardly extending protuberances or a male pattern on the cyllndrical surface of the roll. The male pattern on the embossing roll s i preferably produced by intaglio etching. The truncated, pyramid-:~
~ shaped protuberances are preferably of such a size that from about i s-20 to about 250 protuberances are preeent in a one lineal lnch -~
segment of the roll. In this case, the other roll 24 may be provided with a resilient rubber covering, i.e., a neoprene or . , , silastic rubber, preferably having a hardness of about 35 Durometer to about 95 Durometer. The backup or pressure roll 24 is press-d against the embossing roll 23 by suitable means (not shown) to apply pressure of from about 50 pounds per lineal inch to about 500 pound~ per lineal inch between the nips of the rolls. Prefer~
ably, one or both of the embos~ing rolls 23 and 24 are hollow and are provited with conduit means (not shown) whereby a cooling fluit may be circulated through one or both roll~ to chill tha -~
fllm and to ~et the embossed pattern into the film before it t~ .
Ieaves the rolls. After passlng from the ombosslng roll, the embossed film 10 18 then wound onto a ~torage roll 25 whlch may be packaged and old as 1~ or may be subsequently slit lnto a ~maller dlameter and shorter length roll~ for ~ub~equent ale.
Whlle lt 1~ preferred to us- a slngle embo~sed motal roller and a rubber covered backup roller to produce the fllm of the present inventlon, the fllm may also be produced by feedlng .
tap/ ~)`Y
-- 105;~9~8 the heated film lnto the nlps of a palr of matchet, engrsved rollers, l.e., one roller ~avlng a ral~ed embossment on lt~ surface and the other roller havlng a matchlng depressed engravlng adapted to match and recelve the ralsed e~bo~sment~ on the other roller.
Prlor to lntroduction of the unembossed web 21 into the embosslng rollers, the web may be heated by any suitable means (not shown), e.g., by belng passed between infrared radiant heaters or gas powered radiant heaters, by passage through hot alr ovens, by passage over heated metal rollers, or any other sultable means, ln order to ralse the temperature of the film to that which is suitable for providlng a deep and sharp impresslon when it is received ln the nip of the embo~slng rollers.
The embossed thermoplastic fllms of the present invention made using film produced from low density polyethylene resin have -been found to have excellent physical characteristics. These embossed polyethylene films which have had an embossed depth of from about 2.5 mils to about 10 mils have been found to have a modulus (standard lZ secant--A.S.T.M. D882-67, Nethot A) of from - -about 8,000 lbs/in2 to about 20,000 lbs/in2 in the machine diroc-tion and from about 8,000 lbs/in2 to about 20,000 lbs/in2 in the transverse direction when using the truncated pyramid pattern embossing rolls described hereinbefore on the films made as described above. These embossed films had tenslle strengths (measured at 25% elongation--A.S.T.M. D882-67, Nethod A) ln the ;~
rang4 of from about 350 gm~/ln to about 1200 gms/in. These mbossed films had a gloss of from about 3.0 to about 10.0 polnt~
a- determlned by a Gardner Gloss Neter employing a 45 h-ad (~.S.T.M. D2457-65T). The process conditions utillzed to produco the above embossod films lncluded raislng the te~peratur- of th~ -moving fllm ln a heatlng zone to a temperature in the range of from about 220F to about 250F. Tho te~peraturo on the outer fac- of the metal embosslng roll was maintalned ln the range of - from about 70-F to about 170F lower than the crystallln~ ~oltlng dapl (b~--. . .
~` 105;~9f~8 temperature of the polyethylene u~ed to make the fllm. The roll face te~perature of the rubber backup roll was maintalned in the range of from about 125F to about 180F lower than the crystalllne melting temperature of the polyethylene used to make the film.-Liquid coolant was supplied to the embos~ing roll and maintained ln a temperature range of from about 20F to about 150F. Cooling liquid was also supplied to the rubber backup roll snd the tempera-ture of the coolant was maintained in the range of from about 5F
to about 100F.
10When using recirculating hot air ovens as a heat source to produce the embossed film of the present invention, polyethylene embo~sed films having a thickness of from about 0.50 mils to about 12.0 mils were embossed successfully using heated air applied to each side of the film having an air temperature ranging from about ~ 200F to about 800F. i ;' While there has been described what i8 at pre~ent considered preferred embodiments of the pre~ent invention, it will be apparent to those skilled in the srt that various modifications and changes may be made without departing from the essence of the invention. It i9 intended to cover herein all quch modlfications as come within the true scope and spirit of the following claims.
,~ ,. .
., .
.
:
tap/
. .
~05'~968 ohown in U S Patent Re 23,glO ~ S Patent 3,137,746 dlsclo~es a film having a hexagonal~ raised pattern on ooe surface thereof .. . .
whlch 1~ subsequently oriented and slit between the embos~ments to produce a porous film The hexagons are lnltlally arranged 80 that contlnuous valleys exist on two opposite sides of the lndlvldual rows of protuberances Embossing patterns as shown in the foregoing patents produce an embossed film which i8 deficient in strength in one or more directions of the film by virtue of the fact t4at continuous valley6 separate one or more of the rows of aligned embossments ; When the film begins to tear along this line, slight effort is required to continue the tear from one site of the film to the , ~ : -other Atditionally, films having t-he foregoing pattern arrah~e-ments to not provide as much resistance to edge curl as is desired in modern embossed film which requires resistance to tension in the longitudinal or machine direction in order to be successf~lly utllized on high speet converting equlpment, l e , diaper-making ,`', machlnes. ,~
Thus, it can be seèn that the film embossing art is in neet of an embossed thermoplastic film which will provide a hish resistance to edge curl and which has a high resistance to tear in at least one of the longltudlnal or transverse dlrections o~
the film Summarv of the Invention i It 18 an ob~ect of the presont invention to provite an `~ mbossed thermopla~tic fllm havlng a high resistance to edge curl ~hen ~ub~ected to stress ln the longltudinal dlrectlon It i8 a further ob~ect of the present lnvontlon to provlde a thermoplastlc embossed film which has a hi8h re81~tanc-to toar along at lea~t one of the ~aJor axe~ of the fil~
It i~ a Jtlll further ob~ect of the present lnventlonto provlde a thermoplastlc embos~ed fll~ whlch ha~ a ~harp, well d-flned, ~mall embossed pattern thereon .
_ 3 _ V,,, O , .. . ...
It is another ob~ect of the present lnventlon to provlte a thermoplastlc embossed film whlch has deslrable "hand" and low gloss.
The thermoplastlc embossed film of the present lnventlon is characterlzed ln that one surface of the film is provldet wlth a plurallty of rows of substantlally truncated, parallelogram-shapet protuberances extenting substantially perpenticular to both of the axes of the fllm. The rows of protuberances which are aligned with one of the axes are separated by continuous valleys which extend from one free etge of the film to the other. The rows of protuberances which are alinged with the other of the axes are separated by a plurallty of short alignet valleys, each valley having a length substantially equal to the length of the base of one of the protuberances.
Brief Descrlptlon of the Drawing FIGURE 1 is a perspective view of an embosset thermo-plastic sheet of the present invention;
FIGURE 2 is an enlarget perspective view of the top or the male surface of the thermoplastlc embossed fllm of the present lnvention;
FIGURE 3 i8 a cross-sectional view of the film of FIGURE 2 along the line 3-3;
FIGURE 4 18 a cross-sectional view of the film of FIGURE 2 along the llne 4-4, ant FIGURE S i8 a schematic view of an apparatus for pro-ducing the embossed film of the present invention.
Description of the Preferret Embodiments - Referring noP to FIGURE 1, there i8 seen a thermoplastlc . mbossed sheet of film of the present invention deslgnated generally by the numeral 10, Phich has longltudlnally extending dges 11 and lla and transversely extendlng edges 12 and 12a.
; Sh- fllm has an upper surface designated by the nu~eral 13 and a lower surface desi~nated by the nu~eral 14.
d-p/ ~ ~
~OS'~968 The embos~ed fllm ~hown ln FIGURE 1 has been produced by feedlng a contlnuous length of fllm lnto the nlp of sn embo~sing roll along the machlne dlrectlon or longltudlnal dlrectlon a~
indicated by the arrow marked "MD" The transverse direction is marked by the arrow wlth the legend "TD"
As seen more clearly in FIGURE 2, the embosset fllm of thls inventlon is provided with a plurality of parallelogram-shaped protuberances designated generally by the nu~eral 15, all of which extend upwardly out of the plane of the film from its upper surface 13 The protuberances are pyramidal-shaped and more preferably truncated pyramidal-shaped As can be seen, the protuberance~ are arranged in longltudinally extent~ng or machlne direction rows 16 and transverse or cross direction rows 17 The - series of ad~acent, longitudinally extending rows of protuberances 16 are separated by continuously extending valleys or depression~
18 whlch extend from the upper edge 12 to the lower edge 12a over the entire length in the machine direction of the fil~ The rows 17 whlch extend ln the transverse direction or acro6s the width of the fllm 10 are defined by a serie~ of interrupted, short valleys 19 The short valleys 19 have a length which is equal to -~the width of the base "b" of the truncated parallelogr-ms a8 can be seen more clearly ln FIGURE 4 These short valleys 19 are produced and result from the novel pattern wherein the ad~acent protuberances of each row in the longitudinally extending dlrectlon and ln the transversely extending direction are offset from each --~
~- other by a width whlch is ~ub~tantlally equal to one-half of the ba-e "b" of each of the protuberances as seen ln PIGURE 2 ~8 seen more clearly in FIGURES 3 and 4, each protuber-nce 15 has a helght inticatet by the letter "h" The protubor-nces all extent upwardly out of the plane of the fll~ as ~een ~ore clearly ln FIGURES 3 and 4 The sldes 20 of the protuberanc-- ;
aro lncllned at an angle "alpha" to the plan- of the fllm Thl~
; ngle ~ay be from about 20 tegrees to about 75 degr-e~ The -- S --t-p/ ~
-~05Z968 protuberances generally may have a base width "b" of from about 4 mils to about 50 mils. The protuberances have a height "h" of from about 2 mils to about 20 mlls. In general, the embossed films of this invention are prepared from thermoplastic films having an initial thickness of from about 0.5 mils to about 10 mils.
The particular shape of the protuberances of the embossed film of the present invention is not ~ritical, i.e., they may be in various forms. They may be in the form of squares, diamonds, hemispheres, but generally are preferred to be parallelogram type protuberances. Additionally, in the most preferred form, the protuberances will have generally truncated or flat tops whether t they be pyramid, diamond or other shape~.
The embossed film of the present invention can be prepared from any suitable thermoplastic material, particularly .~
/ the homopolymers and copolymers of alpha-olefins having 2 or 4 carbon atoms, e.g.-, medium, low and high density polyethylene, .'J polypropylene, polybutene-l, and copolymers thereof with each ~ other and with other polymerizable comonomers. Also sultable are '~ 20 films made from polymerized and copolymerized vinyl monomers such as polyvinyl chloride, polyvinylidene chloride, polystyrene and other such type films. Other films that may be embossed include polyethylene terephthalate (Mylar*), polyvinyl acetate, Ionomer, polyvinyl alcohol, Nylon and other polyamides, cellulosics such ;
as cellulose acetate or butyrate, styrene-nitrile type copolymers and graft polymers. Additionally, embossed films may be made from multilayer films, for example, films such as polyethylene:Nylon, HDPE:LDPE:HDPE, LDPE:polyvinyl acetate:LDPE, LDPE:polypropylene: -LDPE, and others.
The embossed film of the present invention may be pre-pared by any suitable means by utilizing a preformed web of film and passing it between embossing rollers, or extruding molten * trademark dap/~
. ; ,.
-lOSZ968 thermoplastic from a slot die tirectly into the nips of a palr of embossing rollers. As seen in FIGURE 5, an unembos~ed fllm web 21, whlch may be preformet or extruted from a slot dle as de~crlbed above, i8 pa~sed into the nlp 22 of a palr of normally contactlng embossing rolls 23 and 24. If preformet film is u~ed, the film 18 heatet by any suitable heating means (not shown) to a suitable temperature for embossing prior to entering the nip of the emboss-ing rolls. One embossing roll, for example, roll 23, may be a .
hollow steel cylinder having the truncatet pyramit pattern described above engraved on its surface to provide an upwardly extending protuberances or a male pattern on the cyllndrical surface of the roll. The male pattern on the embossing roll s i preferably produced by intaglio etching. The truncated, pyramid-:~
~ shaped protuberances are preferably of such a size that from about i s-20 to about 250 protuberances are preeent in a one lineal lnch -~
segment of the roll. In this case, the other roll 24 may be provided with a resilient rubber covering, i.e., a neoprene or . , , silastic rubber, preferably having a hardness of about 35 Durometer to about 95 Durometer. The backup or pressure roll 24 is press-d against the embossing roll 23 by suitable means (not shown) to apply pressure of from about 50 pounds per lineal inch to about 500 pound~ per lineal inch between the nips of the rolls. Prefer~
ably, one or both of the embos~ing rolls 23 and 24 are hollow and are provited with conduit means (not shown) whereby a cooling fluit may be circulated through one or both roll~ to chill tha -~
fllm and to ~et the embossed pattern into the film before it t~ .
Ieaves the rolls. After passlng from the ombosslng roll, the embossed film 10 18 then wound onto a ~torage roll 25 whlch may be packaged and old as 1~ or may be subsequently slit lnto a ~maller dlameter and shorter length roll~ for ~ub~equent ale.
Whlle lt 1~ preferred to us- a slngle embo~sed motal roller and a rubber covered backup roller to produce the fllm of the present inventlon, the fllm may also be produced by feedlng .
tap/ ~)`Y
-- 105;~9~8 the heated film lnto the nlps of a palr of matchet, engrsved rollers, l.e., one roller ~avlng a ral~ed embossment on lt~ surface and the other roller havlng a matchlng depressed engravlng adapted to match and recelve the ralsed e~bo~sment~ on the other roller.
Prlor to lntroduction of the unembossed web 21 into the embosslng rollers, the web may be heated by any suitable means (not shown), e.g., by belng passed between infrared radiant heaters or gas powered radiant heaters, by passage through hot alr ovens, by passage over heated metal rollers, or any other sultable means, ln order to ralse the temperature of the film to that which is suitable for providlng a deep and sharp impresslon when it is received ln the nip of the embo~slng rollers.
The embossed thermoplastic fllms of the present invention made using film produced from low density polyethylene resin have -been found to have excellent physical characteristics. These embossed polyethylene films which have had an embossed depth of from about 2.5 mils to about 10 mils have been found to have a modulus (standard lZ secant--A.S.T.M. D882-67, Nethot A) of from - -about 8,000 lbs/in2 to about 20,000 lbs/in2 in the machine diroc-tion and from about 8,000 lbs/in2 to about 20,000 lbs/in2 in the transverse direction when using the truncated pyramid pattern embossing rolls described hereinbefore on the films made as described above. These embossed films had tenslle strengths (measured at 25% elongation--A.S.T.M. D882-67, Nethod A) ln the ;~
rang4 of from about 350 gm~/ln to about 1200 gms/in. These mbossed films had a gloss of from about 3.0 to about 10.0 polnt~
a- determlned by a Gardner Gloss Neter employing a 45 h-ad (~.S.T.M. D2457-65T). The process conditions utillzed to produco the above embossod films lncluded raislng the te~peratur- of th~ -moving fllm ln a heatlng zone to a temperature in the range of from about 220F to about 250F. Tho te~peraturo on the outer fac- of the metal embosslng roll was maintalned ln the range of - from about 70-F to about 170F lower than the crystallln~ ~oltlng dapl (b~--. . .
~` 105;~9f~8 temperature of the polyethylene u~ed to make the fllm. The roll face te~perature of the rubber backup roll was maintalned in the range of from about 125F to about 180F lower than the crystalllne melting temperature of the polyethylene used to make the film.-Liquid coolant was supplied to the embos~ing roll and maintained ln a temperature range of from about 20F to about 150F. Cooling liquid was also supplied to the rubber backup roll snd the tempera-ture of the coolant was maintained in the range of from about 5F
to about 100F.
10When using recirculating hot air ovens as a heat source to produce the embossed film of the present invention, polyethylene embo~sed films having a thickness of from about 0.50 mils to about 12.0 mils were embossed successfully using heated air applied to each side of the film having an air temperature ranging from about ~ 200F to about 800F. i ;' While there has been described what i8 at pre~ent considered preferred embodiments of the pre~ent invention, it will be apparent to those skilled in the srt that various modifications and changes may be made without departing from the essence of the invention. It i9 intended to cover herein all quch modlfications as come within the true scope and spirit of the following claims.
,~ ,. .
., .
.
:
tap/
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An embossed length of thermoplastic film character-ized in that one surface of the film is provided with a plurality of rows of substantially truncated, parallelogram-shaped protuberances extending substantially perpendicular to both the longitudinal and transverse axis of said length of film, the rows of protuberances aligned with one of said axes being separated by continuous valleys extending from one free edge of said film to the other free edge, the rows of protuberances aligned with the other of said axes being separated by a plurality of aligned short valleys, each valley having a length substantially equal to the length of the base of one of said protuberances.
2. The embossed film of claim 1 wherein said one of said axes is said longitudinal axis.
3. The embossed film of claim 1 wherein said one of said axes is said transverse axis.
4. The embossed film of claim 1 wherein said parallelo-gram-shaped protuberances are pyramid-shaped.
5. The embossed film of claim 4 wherein the sidewall of said pyramid-shaped protuberances have an angle between about 20 degrees to about 75 degrees to the plane of the film.
6. The embossed film of claim 1 wherein said length of the base of one of said protuberances is from about 4 mils to about 50 mils.
7. The embossed film of claim 1 wherein said pro-tuberances are in the shape of a diamond.
8. The embossed film of claim 1 wherein said pro-tuberances have a base length of from about 4 mils to about 50 mils and a height of from about 2 mils to about 20 mils.
9, The embossed film of claim 1 wherein salt film is produced by pressing a heated length of thermoplastic film against an embossing means having substantially truncated, parallelogram-shaped protuberances extending out from the surface thereof.
10. The embossed film of claim 1 wherein said length of embossed film is resistant to edge curl when subjected to stress in the machine direction.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44436674A | 1974-02-21 | 1974-02-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1052968A true CA1052968A (en) | 1979-04-24 |
Family
ID=23764596
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA219,314A Expired CA1052968A (en) | 1974-02-21 | 1975-02-04 | Embossed thermoplastic material |
Country Status (4)
| Country | Link |
|---|---|
| BE (1) | BE825551A (en) |
| CA (1) | CA1052968A (en) |
| FR (1) | FR2261860B1 (en) |
| GB (1) | GB1493512A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554093A (en) * | 1993-06-28 | 1996-09-10 | Dowbrands L.P. | Flexible thermoplastic containers having a visual pattern thereon |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GR70771B (en) * | 1978-07-24 | 1983-03-22 | Thprocter & Gamble Company | |
| US4436520A (en) * | 1981-12-21 | 1984-03-13 | Exxon Research & Engineering Co. | Low gloss films of enhanced adhesion |
| US5234633A (en) * | 1987-12-28 | 1993-08-10 | Canon Kabushiki Kaisha | Cast molding die and process for producing information recording medium using the same |
| EP0323225A3 (en) * | 1987-12-28 | 1990-04-25 | Canon Kabushiki Kaisha | Cast molding die and process for producing information recording medium using the same |
| NL8802484A (en) * | 1988-10-10 | 1990-05-01 | Tredegar Film Products B V | PLASTIC FOIL OF A RELIEF PATTERN, METHOD OF MANUFACTURING THE SAME, AND PACKAGING MATERIAL INCLUDING SUCH FOIL. |
| DE19611665C1 (en) * | 1996-03-25 | 1997-10-23 | 4 P Folie Forchheim Gmbh | Packaging sleeve |
| GB2311752B (en) * | 1996-04-04 | 2000-09-13 | Courtaulds Chemicals | Production and use of plastics film |
| DE19909839B4 (en) * | 1999-03-06 | 2004-12-23 | Huhtamaki Forchheim Zweigniederlassung Der Huhtamaki Deutschland Gmbh & Co. Kg | wrapper |
| US6537407B1 (en) | 2000-09-06 | 2003-03-25 | Acordis Acetate Chemicals Limited | Process for the manufacture of an improved laminated material |
| EP3426479A1 (en) * | 2016-03-08 | 2019-01-16 | Pfnonwovens, Llc | Three-dimensionally patterned non-woven having stress recovery |
-
1975
- 1975-02-04 CA CA219,314A patent/CA1052968A/en not_active Expired
- 1975-02-06 GB GB515775A patent/GB1493512A/en not_active Expired
- 1975-02-14 BE BE153376A patent/BE825551A/en not_active IP Right Cessation
- 1975-02-17 FR FR7504891A patent/FR2261860B1/fr not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554093A (en) * | 1993-06-28 | 1996-09-10 | Dowbrands L.P. | Flexible thermoplastic containers having a visual pattern thereon |
| US5618111A (en) * | 1993-06-28 | 1997-04-08 | Dowbrands L.P. | Flexible thermoplastic containers having visual pattern thereon |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2261860A1 (en) | 1975-09-19 |
| FR2261860B1 (en) | 1978-10-06 |
| GB1493512A (en) | 1977-11-30 |
| BE825551A (en) | 1975-08-14 |
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