CA1174555A - Method for protecting lumber - Google Patents
Method for protecting lumberInfo
- Publication number
- CA1174555A CA1174555A CA000352849A CA352849A CA1174555A CA 1174555 A CA1174555 A CA 1174555A CA 000352849 A CA000352849 A CA 000352849A CA 352849 A CA352849 A CA 352849A CA 1174555 A CA1174555 A CA 1174555A
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- CA
- Canada
- Prior art keywords
- lumber
- panels
- fabric
- wrapping material
- aluminum
- 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
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Abstract
ABSTRACT OF THE DISCLOSURE
A method for protecting lumber from soiling and warping, during transportation and outdoor storage, is disclosed. Stacks of lumber are covered with a wrapping material comprising a woven oriented polyolefin tape structure coated with a polyolefin containing an aluminum, brass or bronze metallic filler. The metallic filler is present in an amount sufficient to provide a light trans-mittance through the wrapping material of less than about 30% in the 450 to 700 nm range e.g. in amounts of 0.75 to 4.5% metallic filler when the thickness of the coating is between about 15 and 50 µm. The polyolefin is either polyethylene or polypropylene.
A method for protecting lumber from soiling and warping, during transportation and outdoor storage, is disclosed. Stacks of lumber are covered with a wrapping material comprising a woven oriented polyolefin tape structure coated with a polyolefin containing an aluminum, brass or bronze metallic filler. The metallic filler is present in an amount sufficient to provide a light trans-mittance through the wrapping material of less than about 30% in the 450 to 700 nm range e.g. in amounts of 0.75 to 4.5% metallic filler when the thickness of the coating is between about 15 and 50 µm. The polyolefin is either polyethylene or polypropylene.
Description
i~ 745iSS
MET~OD FOR PROTECTING IUMEE:R
The pre~ent invention relate~ to a method for protecting ~tacks o~ lumber, during transportation and ~torage outdoors.
During tran~portation and torage o~ lumbe:r~
esp~ially dre~sed lumber~ it i8 desir~b l~ to protect th~
lumber from the vagarles o~ the weather, in order to pre-vent soillng and~or watPr ætaining of the lumber.
It i~ known to co~er lumber ~ith a wr~pping ~aterial. Example~ of such wrapping materials are a wo~en glas~ fibre web laminated on both`side~ to kra~t paper, a ~erim o~ ~oven polyole~in tape~ laminated to kra~t p~per, clear pol~ethylene ~ilm, polyethylene ~ilm ~illed with carbon black pigment, and a ~crim o~ Noven polyole~in tapes 15 : coated with a layer Or pol~ethylene ~illed with TiO2. Ih general the kra~t paper laminates tend to ~e dama~ed dur~ng long distance transportation, which may lead to los~ of protection. Lumber wrapped ln the a~orementioned polyet~y-lene ~ilm m~terials tend to become water stained~ mildewed Q and/or warped.
an ob~ect o~ the pre3ent ~nvention to pro-~ide a method o~ protectin~ lumber which tend~ to o~ercome the d~lci~ncles Or methods o~ the prior artc Accordingl~ tho present inventio~ provide~ a method ~or protectlng lumbe~ comprl~ing co~ering a ~tack o~
lumber on at least its upper, 3ide and end ~ur~ces with a wrapping mate~ial selected ~rom the group con~l~ting o~
a) a fabric made ~rom wo~en oriented tape~ o~ pol~ethylene, ~aid ~abric be~ng coated with a layer o~ polyethylene at least about 15 ~m in thickne~s containin~ a particulate ~' ~ 7~S S 5 metallic ~iller ~elected ~rom the group cons~ sting of aluminum, brass and bronze, in an amount ~u~ficient to provide a light transmitt~nce through the wrapping ma-terial in the 450 to 700 nm wavelength range o~ less than about 30~, and b) a ~abric made ~rom woven oriented tapes of polypropylene, ~aid ~abric being coated with a layer of polypropylene at lea~t about 15 ~m in thickness con-taining a particulate met~llic ~iller selected from the group consisting o~ aluminum, brass and bronze, in an amount su~icient to provide a light transmittance through the wrapping mæterial in the 450 to 700 nm wa~e-length range o~ less than about 30~.
In a pre~erred embodiment o~ the me~hod Q~ the pre~ent invention the wrapping m~terial has a coating containing aluminum particulate ~iller, especially aluminum in ~lake ~orm.
In Ano~her embodiment the ~abric o~ ~oven tapeæ
has a crowdedness of between about 20~ and 70~ in the we~t direction and between about 30% and 100~ in the warp d~rection. Crowdedness i~ de~ined as the ratio, expre3sed as a percentage, of the area o~ the fabric occupied by either the ~e~t or the warp tapes to the total area of the fabric.
In yet another embodiment the particulate metallic ~iller i8 pre8ent in an amount su~ficien~ to provide a light transmittance in the 450 to 700 nm wavelength range o~ les~ than about 2~%.
The pres2nt invention also pro~ide~ a lumber co~r hav~ng a t~p panel, two ~ide panels and two end panel8, ~aid panels being made o~ a wrapping material selected ~rom the group con~i~tlng o~ a) a fabric made rrom ~ro~ren orlented tapes o~ polyethylene, said ~abrlc being co~ted with a layer Or polyethylene at least about 15 ,um in thlckness containing a partlculate metallic 35 ~iller selected from the group consisting o~ aluminum, bras~ and bronze, in an ~mount su~ricient to provide a light transmittance through the wrapping material in ~7~S55 the 450 to 700 nm wavelength range o~ less than about 30%, and b) a fabric made from woven oriented tapes of polypropylene~ said ~abric being co~ted ~ith a layer of polypropylene at least about 15 um in thiGkne~s con-taining a p~rticulate metallic ~iller ,selected ~rom thegroup consi~ting of aluminwm, brass and bron~e J in an amount sufficient to provide a light transmittance through the wrapping material in the 450 to 700 nm w~velsn~th range o~ less than about 30~, said panels being o~ a size such that the cover substantially con~orm~ to a rectangul~r pri~oidal ~tack o~ lumber.
I~ a preferred embodiment of the lumber cover o~
the present invention the sd~oining edges o~ the panel~
are he~t sea}ed.
In a ~urther embodiment the ad~oining edges of the panel~ are ~ewn.
In another embodiment the end and top panels are made ~rom a ~ingle piece o~ the wrapping material.
In yet another embodiment the coating o~ the lumber co~er is between about 15 ~m and 50 ~m and contains aluminum as the particulate metallic ~iller.
In a further embodiment the wrapping material o~
the lumber co~er is polyethylene.
The present in~ention ~urther provides a ~tack of lumber co~ered on at least its upper, side and end surfaces with a wrapping material seleeted ~rom the ~roup consi~ting Or a) a ~abxic made ~rom woven oriented tapes of polye~hy-lene, ~ald Pabric being c~ated with a layer o~ pol~ethylene at least about 15 ~m in thickness containlng a particula~e mekall~c ~iller ~elected ~rom the group consi~ting of aluminumJ br~ and bronæe in an.amount su~icient to pro-vide a light transmittance through the wrapplng materi81 ln the 450 to 700 nm wavelength range o~ le~ than about 30~, and b) a ~abric made ~rom wo~en oriented tapes o~ poly-propylene said rabric being coated with a layer o~ polyprop-lene at least about 15 ~m ln thickness containing a partic-~3L7~
ulate ~etallic ~iller selected rrom the group consisting ofaluminum, bra~ and bronze in an amount su~ieient to pro-vide a light transmlttance through the wrapping material ~n the 450 to 700 nm wavelength range o~ less than about 30~.
In a pre~erred embodiment of the stack Or lumber Or the present invention the coating of` the wrapping m~-terial contains an aluminum particulat0 ~iller, especially aluminum in flake form~
In another embodiment the fabric o~ ~oven tap~s ha~ a crowdednes~ o~ between about 20% and 70% in th~ Ne~t direction and between ~bout 30% and 100~ ~n the ~rp direc-tion.
I~ yet another embodiment the oriented t~pes o~
the ~abr~c are made ~rom a polyethylene, havlng a density between 0.940 and O.g70 g/em3, which is a homopolymer of eth~lene, a copolymer of et~ylene and a C3-C8 l-ole~in or blend~ thereo~ espec~lly a homopolymer o~ ethylene and the coating i8 made ~rom a polyethylene, ha~ing a density between 0.910 ~nd 0~945 g/cm3, which i3 a homopolymer o~
ethylene, a copolymer o~ ethylene and a C3-C8 l-ole~in or blend~ thereof~ especially a copolymer o~ ethylene and butene-1.
In a ~urther embodiment the coating Or the wrap-ping material has a thicknes~ between about 15 ~m and 50 ~m~
preferably in the ~ange o~ 20 ~m to 30 ~m.
It Will be understood by tho~e ski~led in the art that t~p~s made ~rom h~m~polymers o~ propylene ~ay be ori-ented and are ~ui~abl~ ~or maklng the ~abric portion o~ the wrapp:in~ material. Xt will ~180 be understood that copoly-mer~ o~ propylene e.g~ wi~h eth~lene are ~uitable rOr co~ting the polypropylene fabric.
me pre~ent invention relates to a method ~or protecting lumber~
It is known that polyethylene containing be tween 1 and 5~ of flnely di~ided TiO2 i~ op~que to li~ht having a wavelength of le~s than about 400 nm, However structures o~ wo~en oriented poly~thylene tapas eoated with polyethy lene containing ~inely divided TiO2 tend to allow lumber wrapped therein to "s~reat"~ It is believed that s~reatlng 5 is caused by heating of the lumber to s.n exterlt suf~icient to cause e~aporation o~ the moiQture within the lumber.
Retention o~ the moisture 80 evaporated within the con~ines Or the wrapping material may lead to mould formation on the ~ur~ce o~ tAe lumber and/or staining.
Replacement of TiO2 in the polyethylene coating with carbon black ~mprove~ the opacity o~ the ~tructure to light, by broadening the wa~elength spectrum o~ llght ~hich is blocked by the pig~ent, to a wa~elength of le~ th~n about 700 nmO While the use o~ carbon black ~t a concentra-tion o~ about 2% pre~ents.sub~tantially all light~ having a waYelength o~ lesæ than about 700 nm, ~rom pas~ing through the ~aterial, its use doe~ not appear to materially lessen the problem o~ sweating. Staining o~ the lumber does not appear to be as evident when a coating of polye~hylene con taining carbon black i8 used, however, but the lumber has a tendency to wsrp. Su~h warping is believed to be caused by rapld dr~ing of the boards on the out~ide of the lumber stack.
Although not wishing to be bound by any theory~
it appears that the present invention tend~ to overcome the problem~ presented by the pr~or methods used ~or wrapping lumber, by minimiæing the amount Or moi~ure removed ~rom the lumber and le~sening the chance~ o~ light-i~duced stain-ine 0~ the lumb~r~ It appe~r~ that, in accordance with the pre~ent invention, total op~city to light is not required and that light trans~it-tances in the wavelen~th range o~ 450 to 700 nm o~ le~s than 30% is su~icient. Light transmit-tances o~ less than 20~ are pre~erred, however.
Technique~ ~or manu~acturlng eoated woven polyole~in materials are kn~l. For example, the wo~en ~abric required , 7 ~ S ~ 5 ~or the pre~ent invention ma~ be wo~en on a loom having a we~t supply bobbin outside the ~hed o~ warp tape3~ ~rom oriented tapes slit longitudlnally from sheet~ o~ polyethy-lene or polypropylene ~ilm. me woven ~abrlc may then be transported below and past a ~ransversely positioned slot die.
A~ the ~abric passes below the slot d:le, a blend of the coat-ing polyole~in i.e. polyethylene or pol~propylene, and the particulate metallic filler i5 ex~rud~d through the slot die onto the rabric, ~hus ~orming a thin coating on the woYen ~abric. me wrapping materials used in the present in-~ention are con~en~ently wo~en and coated in width~ Or be-tween about 245 cm and 275 cm, although there is no reason why other width~ could not be used~ In the eYent that ma~erial o~ greater uidth is requlred to ~rap stack~ o~
lumber, two or more ~heets may be cut ~rom a roll o~ the wrapping material and then m~y be hea~ sealed together a~ong their longitudinal edges. Heat se~ling m~y be ac-complished by placing one sheet, with its coatlng facing upwards3 longitudinally ad~acent to a second sheet, with its coating ~acing downwards. me longitudinal edges o~ the two ~heets are o~erlapped so that the coating~ are in ~sce-to-race relatlonship and the coat~ngs t~en are ~oined by hot air ~ealing in a known manner, Further sheets may be heat-sealed to these two in a gimilar manner, in orcler to obtain wrapping material of e~en greater width. In an embadim~nt Or the in~ention the sheet~ ~ay be eut to a len~th e~ual to twice the he~ght plu~ the length o~ the lumber ~tack to be co~ered.
~or convenlence three sheet~ may be cut longitu-dinally; two o~ them ~nto widths corre3pondlng to the height and one o~ them into a width corra~ponding to ~he width o~ the lumber ~tack to be co~ered~ m e ~heet~ may then be hea~ ~ealed as hereinbefore described, or ~ewn. m e longitudinal ~oints so ~ormed may be used to guide the placement of the wrapp~ng material o~er the lumber.
~7~ ~ S S
A lumber cover may be pre~ormed by folding and sewing the wrapping material into a ~iv~-panelled cover i.e. t~o end two ~ide~ and a top. Alternati~ely~ the lumber cover may be ~ormed by foldlng and stapline or otherwi~e securing ~he wrapping material a~ter covering the lumber stack.
The wrapping materials u3ed in ~e present in-vention are su~icien~ly durable i~ the wo~en fabric portion is loosely woven i.e. i~ a ~cri.m~ It i~ pre~erred tha~ the construction o~ the scrim is æu~ficient to ~part a grab ~trength to the wrapping material in either the ~axp or we~t direc~ons o~ at least about 110 ~ and more partic-ul~rly between about 175 and 310 ~, grab ~trength being measured by the procedure of ASTM-D1682 640 Wrapping material~ ha~ing the desired le~el o~
grab ~rength may be made ~rom a scrim having oriented warp and we~t tapes o~ polyethylene having a density between 0.940 and 0.970 g~cm3 and a coating o~ polyethylene ha~ng a den~ity between 0.910 and 0O945 g/cm3. m e scrim may be constructed ~or example ~rom warp tape~ ha~ing A width between about 2.0 mm and 3.0 mm and a linear density be-twee~ about 650 and 1100 dtex and we~t tapes having a width between about 2.5 mm and 4.4 mm and a linear density between about 1050 and 1250 dtex, wherein the weave has betw~en about 3.3 and 3.9 ends/cm and 0.9 and 1.5 picks/cm. me coatlng is pre~erably between 15 and 50 ~m in thicknes~ and the concentration o~ aluminum~ bronæeJ or brass in the coat-ine is p~e~erably in the range o~ OJ75 tO 4.5 wt.~o The particle shape o~ the metallic pigment iæ not 3~ critical~ but ~lak~ form~ are p~er~rred. ~he plgment par~icles used in the pre~ent inven~ion need to be o~ a particle ~l~e that is su~iciently small that the extru~ion process i~ no-t hlndered~ In general~ particles which pas~
~ through a 325 mesh TYLER* sie~e are ~uitable.
* denotes trade mark .. .
~ 5 5 me presen-t invention is illu~trated by referen~e to the followlng e~amples:
Example 1 The e~icacies of an embodiment of the present ln~ention and methods of the prior art were compaxed ~ith respect to the ability to suppress mol.~ture evolution ~rom lumber.
Samples oP wr~pping materials, about 33 cm square were taken and weighed. Each ~ample was wrapped around a we~ghed 10 cm x 5 cm x 4 cm block o~ green ash. me b~ccks of green a~h were cut ~xom a l~rger block to minimize the varlæb~llty of moi8tur8 content ~rom block to block~ The ~r~pping material~ fully envelop~d the ash block~ ~nd were stapled thereto. ~he wrapped blocks ~ere placed about 30.5 cm a~ay ~rom a 250 watt bulb of a sunlamp. Each ~r~p ped block ~as e~posed to ~i~ cycles of 30 minute periods of heating, with the su~aD~p on, followed by 30 minute periods o~ cooling, with the ~unla~p off. ~he ~mbient room tem-perature was about 10C. A~ter 12 hour~ the ash block~
were weighed after removing ~rom the wr~appirlg material ~nd drying their ~urf`aces with weighed blotting paper. ~he moist blotting paper wa~ then weighed.
A wrappe~, d2~ign~ted "Clear", used ror comp~rl-son purpose~9 compri~ed ~ scrim o~ oriented tapes, made ~rom a clear polyethylene having a den~ity of o.960 g/Cm3J
in which th~ warp tape~ had a width o~ 2.5 mm and a linear den~ity o~ 1067 dtex.and the we~t tape~ had a width o~
3~38 mm and a l~near donslty o~ 1083 dtex and which had 3.55 ends/em and ~.58 pick~/cm, coated with a 25 ~m layer Or clear pol~thylen0 havln~ a den8it~ of 0.923 g/cm3.
A ~econd wrapper, desi~nated ~White~, also used ~or comparison purpose~ con~l~ted o~ a scrim, ~imilar to khat o~ the ~Cle~r" wrapper, laminated to a polyethylene ~ilm cont~lnlng about 5~ TiO~ and having a thickne~ o~
25 ~m.
1:~'74SS5 The wrapper de~ignated "AL't, u~ed in the pre-sent invention comprised a scrim o~ oriented tape~ made from ~ clear ethylene homopolymer having a density of o.960 g/cm3, in which the warp tape~ had a width o~ 2.5 mm and 5 a linear density oi~ 667 dtex and the weft tapes had a width oP 4.25 mm ~nd a linear density of 1222 dtex and which had 3.55 ends/cm and 0.9~ picks/cm, coated with a 20 ~m layer o~ a mixture o~ 9 parts of clear polyethylene having a density o~ 0.923 g/cm3, and one part o~ a polyetAylene 10 and aluminum concentrate. me weft crowdednes~ o~ the ~AL"
wrapper is 40% and the warp crowdedness iY 89~
The polyethylene and aluminum concentrate com-prised flake alumlnum available from the Canbro Divi~ion o~ International Bro~ze Powders Ltd. o~ Yalleyfield, Quebec under the trade ~ark LUXOR 950 in a concentration of 25 wt.%
in a pol~rethylene h~ving ~ den~ity of 0.917 g~cm3.
. The result~ of the experiment~ with the "Clear~, :
"White" and "AL" wrapping materials, which ~re ~hown in Table I, indicate the ~fecti~eness o~ the wrapping materlal 20 o~ the present in~rention in reducing the total amount o~
moisture evolved ~rom ~he lumber, and o~ -the amount o~
moisture conderlsed inside the wrapping ~teri~l.
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ss Example 2 Samples of wrapping materials, about 33 cm square ~ere taken and each sample wrapped around & block o~
10 cm x 10 cm ~ 5 cm gr~n m~ple. m e blocks o~ green map~e were cut from a large~ block to mlnimize the variability of moisture content from block to block. Maple was chosen becaus~ o~ its ligh~ uniform colour and high molsture con-tent. The wrapping material~ ~ully enveloped the map~e block~ and were stapled thereto. The wrapped blocks were placed about ~5 cm away ~rom a 250 watt bulb o~ a sunlamp.
Each wrapped block was e~posed to about ten cycles o~ 15 mlnute period~ of heating, with the sunlamp on, ~o}lowed by 60 minute periods o~ coolin~ with the sunlamp of~. After completion Or the ~en cycles each wrapped block was e~posed to six hours of natural sunlight in a w~ndow facing ~outh.
me ~mbient temperature o~ the room wa~ about 10Co Sub-æequent to exposure to the sunlamp and sunlight the blocks of maple were unwrapped and the amount o~ water e~ol~ed and the extent of stainin~ were noted.
Wrapping materials "Clear", "White" and "AL" o~
Example 1 were tested. In addition two ~urther wrapping ma-terials were included for comp~rison purposes. One wrapper~
designated "Black" compr~sed a wo~ren fabric o~ oriented tapes made ~rom a polyethylene having a density of o.960 g/cm3 and con~aining 2 wt.~ carbon black pigment~ in which the ~arp tapes had a width o~ 2.5 mm and a linear den~ity of 889 dtex and the weft tapes a width o~ 4.37 mm and a line~r density o~ 1211 dtex, ~nd which had 3.54 ends/cm and 2.66 picks/cm, eoated on one side wlth a 25 ~m layer o~ polyethylene havlng a den~ity Or 0~923 g/cm3 and containing 2 wt.~ o~ carbon blac~
pigment, and coa~ed on the other slde with a 25 ~m layer of polyethylene ha~ing ~ denslty o~ O.923 g~cm3 ~nd containing 4 wt.~ o~ a blue pigment available ~rom Ampacet Corporation under the trade mark ~MPACET 16431.
The other wrapper, designated ~Paper~Clear~' com-prl~ed one layer o~ 35 lb. kra~t paper~ and a layer of the "Clear" wrapper.
The observations o~ the tests shown in Table II, are a ~urther indication of the e~icacy of the method o~ the present ~nvention.
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~7~55 l-13 -~ he light transmittance~ o~ ~amples o~ "Clear", "White", "Paper/Clear"~ "Black" and IIALII wrapplng material~
were measured using a W -visible spectrophotometer.
The re~ults are shown in Table III.
Table III
~rapperTransmittance_in 400-700 nm range Clear 82-86 White 20-50~
Paper/Clear 0%
Bl~ck 0 AL 26-29~
Five ætac~ Or planed and ~iln dried m~xed pine, spruce and ~ir lumber, each about o.6 m x ~.2 m x 2.4 m were packaged in a wrapping matPria}, de~ignated 'tAL-l", 8imilar to the 11Ah11 wrapper of Example 1 except that the scrim con~truc~ion had 3.54 ends/cm and 1.26 pickæ/cm i.e. having a warp crowdednes~ o~ 88% and a we~t crowdedne~s o~ 54~ and the coating wa~ 25 ~m ~hick containing 2.0 wt.~ of ~la~e aluminum. Ten similar stack~ o~ lumber we~e packaged in the '1Clear" wrapping material of Example l. All of the stacks of lumber were wrapped directly a~ter kiln drying.
~he wrapped stacks o~ lumber were le~t in the open for ~our da~s during the month of September and on the ~i~th day all o~ the wrapped stack~ o~ lumber were tr~nsported on an open ~lat bed truc~ a distance o~ 950 km ~rom the Province o~ Quebec~C~n~da, to New York Stat~, U.S,A. Upon reachin~ the de~tination the moisture conden~tion on the lumber wa~ checked b~ hand and ~isually. There was evidence Or ~o~ture condensation pres~nt on ~tacks wrapped in the "Clear" wrapping materlal~ but little or none present on ~tacks wrapped in ths "AL-l" wrapping ~aterial.
MET~OD FOR PROTECTING IUMEE:R
The pre~ent invention relate~ to a method for protecting ~tacks o~ lumber, during transportation and ~torage outdoors.
During tran~portation and torage o~ lumbe:r~
esp~ially dre~sed lumber~ it i8 desir~b l~ to protect th~
lumber from the vagarles o~ the weather, in order to pre-vent soillng and~or watPr ætaining of the lumber.
It i~ known to co~er lumber ~ith a wr~pping ~aterial. Example~ of such wrapping materials are a wo~en glas~ fibre web laminated on both`side~ to kra~t paper, a ~erim o~ ~oven polyole~in tape~ laminated to kra~t p~per, clear pol~ethylene ~ilm, polyethylene ~ilm ~illed with carbon black pigment, and a ~crim o~ Noven polyole~in tapes 15 : coated with a layer Or pol~ethylene ~illed with TiO2. Ih general the kra~t paper laminates tend to ~e dama~ed dur~ng long distance transportation, which may lead to los~ of protection. Lumber wrapped ln the a~orementioned polyet~y-lene ~ilm m~terials tend to become water stained~ mildewed Q and/or warped.
an ob~ect o~ the pre3ent ~nvention to pro-~ide a method o~ protectin~ lumber which tend~ to o~ercome the d~lci~ncles Or methods o~ the prior artc Accordingl~ tho present inventio~ provide~ a method ~or protectlng lumbe~ comprl~ing co~ering a ~tack o~
lumber on at least its upper, 3ide and end ~ur~ces with a wrapping mate~ial selected ~rom the group con~l~ting o~
a) a fabric made ~rom wo~en oriented tape~ o~ pol~ethylene, ~aid ~abric be~ng coated with a layer o~ polyethylene at least about 15 ~m in thickne~s containin~ a particulate ~' ~ 7~S S 5 metallic ~iller ~elected ~rom the group cons~ sting of aluminum, brass and bronze, in an amount ~u~ficient to provide a light transmitt~nce through the wrapping ma-terial in the 450 to 700 nm wavelength range o~ less than about 30~, and b) a ~abric made ~rom woven oriented tapes of polypropylene, ~aid ~abric being coated with a layer of polypropylene at lea~t about 15 ~m in thickness con-taining a particulate met~llic ~iller selected from the group consisting o~ aluminum, brass and bronze, in an amount su~icient to provide a light transmittance through the wrapping mæterial in the 450 to 700 nm wa~e-length range o~ less than about 30~.
In a pre~erred embodiment o~ the me~hod Q~ the pre~ent invention the wrapping m~terial has a coating containing aluminum particulate ~iller, especially aluminum in ~lake ~orm.
In Ano~her embodiment the ~abric o~ ~oven tapeæ
has a crowdedness of between about 20~ and 70~ in the we~t direction and between about 30% and 100~ in the warp d~rection. Crowdedness i~ de~ined as the ratio, expre3sed as a percentage, of the area o~ the fabric occupied by either the ~e~t or the warp tapes to the total area of the fabric.
In yet another embodiment the particulate metallic ~iller i8 pre8ent in an amount su~ficien~ to provide a light transmittance in the 450 to 700 nm wavelength range o~ les~ than about 2~%.
The pres2nt invention also pro~ide~ a lumber co~r hav~ng a t~p panel, two ~ide panels and two end panel8, ~aid panels being made o~ a wrapping material selected ~rom the group con~i~tlng o~ a) a fabric made rrom ~ro~ren orlented tapes o~ polyethylene, said ~abrlc being co~ted with a layer Or polyethylene at least about 15 ,um in thlckness containing a partlculate metallic 35 ~iller selected from the group consisting o~ aluminum, bras~ and bronze, in an ~mount su~ricient to provide a light transmittance through the wrapping material in ~7~S55 the 450 to 700 nm wavelength range o~ less than about 30%, and b) a fabric made from woven oriented tapes of polypropylene~ said ~abric being co~ted ~ith a layer of polypropylene at least about 15 um in thiGkne~s con-taining a p~rticulate metallic ~iller ,selected ~rom thegroup consi~ting of aluminwm, brass and bron~e J in an amount sufficient to provide a light transmittance through the wrapping material in the 450 to 700 nm w~velsn~th range o~ less than about 30~, said panels being o~ a size such that the cover substantially con~orm~ to a rectangul~r pri~oidal ~tack o~ lumber.
I~ a preferred embodiment of the lumber cover o~
the present invention the sd~oining edges o~ the panel~
are he~t sea}ed.
In a ~urther embodiment the ad~oining edges of the panel~ are ~ewn.
In another embodiment the end and top panels are made ~rom a ~ingle piece o~ the wrapping material.
In yet another embodiment the coating o~ the lumber co~er is between about 15 ~m and 50 ~m and contains aluminum as the particulate metallic ~iller.
In a further embodiment the wrapping material o~
the lumber co~er is polyethylene.
The present in~ention ~urther provides a ~tack of lumber co~ered on at least its upper, side and end surfaces with a wrapping material seleeted ~rom the ~roup consi~ting Or a) a ~abxic made ~rom woven oriented tapes of polye~hy-lene, ~ald Pabric being c~ated with a layer o~ pol~ethylene at least about 15 ~m in thickness containlng a particula~e mekall~c ~iller ~elected ~rom the group consi~ting of aluminumJ br~ and bronæe in an.amount su~icient to pro-vide a light transmittance through the wrapplng materi81 ln the 450 to 700 nm wavelength range o~ le~ than about 30~, and b) a ~abric made ~rom wo~en oriented tapes o~ poly-propylene said rabric being coated with a layer o~ polyprop-lene at least about 15 ~m ln thickness containing a partic-~3L7~
ulate ~etallic ~iller selected rrom the group consisting ofaluminum, bra~ and bronze in an amount su~ieient to pro-vide a light transmlttance through the wrapping material ~n the 450 to 700 nm wavelength range o~ less than about 30~.
In a pre~erred embodiment of the stack Or lumber Or the present invention the coating of` the wrapping m~-terial contains an aluminum particulat0 ~iller, especially aluminum in flake form~
In another embodiment the fabric o~ ~oven tap~s ha~ a crowdednes~ o~ between about 20% and 70% in th~ Ne~t direction and between ~bout 30% and 100~ ~n the ~rp direc-tion.
I~ yet another embodiment the oriented t~pes o~
the ~abr~c are made ~rom a polyethylene, havlng a density between 0.940 and O.g70 g/em3, which is a homopolymer of eth~lene, a copolymer of et~ylene and a C3-C8 l-ole~in or blend~ thereo~ espec~lly a homopolymer o~ ethylene and the coating i8 made ~rom a polyethylene, ha~ing a density between 0.910 ~nd 0~945 g/cm3, which i3 a homopolymer o~
ethylene, a copolymer o~ ethylene and a C3-C8 l-ole~in or blend~ thereof~ especially a copolymer o~ ethylene and butene-1.
In a ~urther embodiment the coating Or the wrap-ping material has a thicknes~ between about 15 ~m and 50 ~m~
preferably in the ~ange o~ 20 ~m to 30 ~m.
It Will be understood by tho~e ski~led in the art that t~p~s made ~rom h~m~polymers o~ propylene ~ay be ori-ented and are ~ui~abl~ ~or maklng the ~abric portion o~ the wrapp:in~ material. Xt will ~180 be understood that copoly-mer~ o~ propylene e.g~ wi~h eth~lene are ~uitable rOr co~ting the polypropylene fabric.
me pre~ent invention relates to a method ~or protecting lumber~
It is known that polyethylene containing be tween 1 and 5~ of flnely di~ided TiO2 i~ op~que to li~ht having a wavelength of le~s than about 400 nm, However structures o~ wo~en oriented poly~thylene tapas eoated with polyethy lene containing ~inely divided TiO2 tend to allow lumber wrapped therein to "s~reat"~ It is believed that s~reatlng 5 is caused by heating of the lumber to s.n exterlt suf~icient to cause e~aporation o~ the moiQture within the lumber.
Retention o~ the moisture 80 evaporated within the con~ines Or the wrapping material may lead to mould formation on the ~ur~ce o~ tAe lumber and/or staining.
Replacement of TiO2 in the polyethylene coating with carbon black ~mprove~ the opacity o~ the ~tructure to light, by broadening the wa~elength spectrum o~ llght ~hich is blocked by the pig~ent, to a wa~elength of le~ th~n about 700 nmO While the use o~ carbon black ~t a concentra-tion o~ about 2% pre~ents.sub~tantially all light~ having a waYelength o~ lesæ than about 700 nm, ~rom pas~ing through the ~aterial, its use doe~ not appear to materially lessen the problem o~ sweating. Staining o~ the lumber does not appear to be as evident when a coating of polye~hylene con taining carbon black i8 used, however, but the lumber has a tendency to wsrp. Su~h warping is believed to be caused by rapld dr~ing of the boards on the out~ide of the lumber stack.
Although not wishing to be bound by any theory~
it appears that the present invention tend~ to overcome the problem~ presented by the pr~or methods used ~or wrapping lumber, by minimiæing the amount Or moi~ure removed ~rom the lumber and le~sening the chance~ o~ light-i~duced stain-ine 0~ the lumb~r~ It appe~r~ that, in accordance with the pre~ent invention, total op~city to light is not required and that light trans~it-tances in the wavelen~th range o~ 450 to 700 nm o~ le~s than 30% is su~icient. Light transmit-tances o~ less than 20~ are pre~erred, however.
Technique~ ~or manu~acturlng eoated woven polyole~in materials are kn~l. For example, the wo~en ~abric required , 7 ~ S ~ 5 ~or the pre~ent invention ma~ be wo~en on a loom having a we~t supply bobbin outside the ~hed o~ warp tape3~ ~rom oriented tapes slit longitudlnally from sheet~ o~ polyethy-lene or polypropylene ~ilm. me woven ~abrlc may then be transported below and past a ~ransversely positioned slot die.
A~ the ~abric passes below the slot d:le, a blend of the coat-ing polyole~in i.e. polyethylene or pol~propylene, and the particulate metallic filler i5 ex~rud~d through the slot die onto the rabric, ~hus ~orming a thin coating on the woYen ~abric. me wrapping materials used in the present in-~ention are con~en~ently wo~en and coated in width~ Or be-tween about 245 cm and 275 cm, although there is no reason why other width~ could not be used~ In the eYent that ma~erial o~ greater uidth is requlred to ~rap stack~ o~
lumber, two or more ~heets may be cut ~rom a roll o~ the wrapping material and then m~y be hea~ sealed together a~ong their longitudinal edges. Heat se~ling m~y be ac-complished by placing one sheet, with its coatlng facing upwards3 longitudinally ad~acent to a second sheet, with its coating ~acing downwards. me longitudinal edges o~ the two ~heets are o~erlapped so that the coating~ are in ~sce-to-race relatlonship and the coat~ngs t~en are ~oined by hot air ~ealing in a known manner, Further sheets may be heat-sealed to these two in a gimilar manner, in orcler to obtain wrapping material of e~en greater width. In an embadim~nt Or the in~ention the sheet~ ~ay be eut to a len~th e~ual to twice the he~ght plu~ the length o~ the lumber ~tack to be co~ered.
~or convenlence three sheet~ may be cut longitu-dinally; two o~ them ~nto widths corre3pondlng to the height and one o~ them into a width corra~ponding to ~he width o~ the lumber ~tack to be co~ered~ m e ~heet~ may then be hea~ ~ealed as hereinbefore described, or ~ewn. m e longitudinal ~oints so ~ormed may be used to guide the placement of the wrapp~ng material o~er the lumber.
~7~ ~ S S
A lumber cover may be pre~ormed by folding and sewing the wrapping material into a ~iv~-panelled cover i.e. t~o end two ~ide~ and a top. Alternati~ely~ the lumber cover may be ~ormed by foldlng and stapline or otherwi~e securing ~he wrapping material a~ter covering the lumber stack.
The wrapping materials u3ed in ~e present in-vention are su~icien~ly durable i~ the wo~en fabric portion is loosely woven i.e. i~ a ~cri.m~ It i~ pre~erred tha~ the construction o~ the scrim is æu~ficient to ~part a grab ~trength to the wrapping material in either the ~axp or we~t direc~ons o~ at least about 110 ~ and more partic-ul~rly between about 175 and 310 ~, grab ~trength being measured by the procedure of ASTM-D1682 640 Wrapping material~ ha~ing the desired le~el o~
grab ~rength may be made ~rom a scrim having oriented warp and we~t tapes o~ polyethylene having a density between 0.940 and 0.970 g~cm3 and a coating o~ polyethylene ha~ng a den~ity between 0.910 and 0O945 g/cm3. m e scrim may be constructed ~or example ~rom warp tape~ ha~ing A width between about 2.0 mm and 3.0 mm and a linear density be-twee~ about 650 and 1100 dtex and we~t tapes having a width between about 2.5 mm and 4.4 mm and a linear density between about 1050 and 1250 dtex, wherein the weave has betw~en about 3.3 and 3.9 ends/cm and 0.9 and 1.5 picks/cm. me coatlng is pre~erably between 15 and 50 ~m in thicknes~ and the concentration o~ aluminum~ bronæeJ or brass in the coat-ine is p~e~erably in the range o~ OJ75 tO 4.5 wt.~o The particle shape o~ the metallic pigment iæ not 3~ critical~ but ~lak~ form~ are p~er~rred. ~he plgment par~icles used in the pre~ent inven~ion need to be o~ a particle ~l~e that is su~iciently small that the extru~ion process i~ no-t hlndered~ In general~ particles which pas~
~ through a 325 mesh TYLER* sie~e are ~uitable.
* denotes trade mark .. .
~ 5 5 me presen-t invention is illu~trated by referen~e to the followlng e~amples:
Example 1 The e~icacies of an embodiment of the present ln~ention and methods of the prior art were compaxed ~ith respect to the ability to suppress mol.~ture evolution ~rom lumber.
Samples oP wr~pping materials, about 33 cm square were taken and weighed. Each ~ample was wrapped around a we~ghed 10 cm x 5 cm x 4 cm block o~ green ash. me b~ccks of green a~h were cut ~xom a l~rger block to minimize the varlæb~llty of moi8tur8 content ~rom block to block~ The ~r~pping material~ fully envelop~d the ash block~ ~nd were stapled thereto. ~he wrapped blocks ~ere placed about 30.5 cm a~ay ~rom a 250 watt bulb of a sunlamp. Each ~r~p ped block ~as e~posed to ~i~ cycles of 30 minute periods of heating, with the su~aD~p on, followed by 30 minute periods o~ cooling, with the ~unla~p off. ~he ~mbient room tem-perature was about 10C. A~ter 12 hour~ the ash block~
were weighed after removing ~rom the wr~appirlg material ~nd drying their ~urf`aces with weighed blotting paper. ~he moist blotting paper wa~ then weighed.
A wrappe~, d2~ign~ted "Clear", used ror comp~rl-son purpose~9 compri~ed ~ scrim o~ oriented tapes, made ~rom a clear polyethylene having a den~ity of o.960 g/Cm3J
in which th~ warp tape~ had a width o~ 2.5 mm and a linear den~ity o~ 1067 dtex.and the we~t tape~ had a width o~
3~38 mm and a l~near donslty o~ 1083 dtex and which had 3.55 ends/em and ~.58 pick~/cm, coated with a 25 ~m layer Or clear pol~thylen0 havln~ a den8it~ of 0.923 g/cm3.
A ~econd wrapper, desi~nated ~White~, also used ~or comparison purpose~ con~l~ted o~ a scrim, ~imilar to khat o~ the ~Cle~r" wrapper, laminated to a polyethylene ~ilm cont~lnlng about 5~ TiO~ and having a thickne~ o~
25 ~m.
1:~'74SS5 The wrapper de~ignated "AL't, u~ed in the pre-sent invention comprised a scrim o~ oriented tape~ made from ~ clear ethylene homopolymer having a density of o.960 g/cm3, in which the warp tape~ had a width o~ 2.5 mm and 5 a linear density oi~ 667 dtex and the weft tapes had a width oP 4.25 mm ~nd a linear density of 1222 dtex and which had 3.55 ends/cm and 0.9~ picks/cm, coated with a 20 ~m layer o~ a mixture o~ 9 parts of clear polyethylene having a density o~ 0.923 g/cm3, and one part o~ a polyetAylene 10 and aluminum concentrate. me weft crowdednes~ o~ the ~AL"
wrapper is 40% and the warp crowdedness iY 89~
The polyethylene and aluminum concentrate com-prised flake alumlnum available from the Canbro Divi~ion o~ International Bro~ze Powders Ltd. o~ Yalleyfield, Quebec under the trade ~ark LUXOR 950 in a concentration of 25 wt.%
in a pol~rethylene h~ving ~ den~ity of 0.917 g~cm3.
. The result~ of the experiment~ with the "Clear~, :
"White" and "AL" wrapping materials, which ~re ~hown in Table I, indicate the ~fecti~eness o~ the wrapping materlal 20 o~ the present in~rention in reducing the total amount o~
moisture evolved ~rom ~he lumber, and o~ -the amount o~
moisture conderlsed inside the wrapping ~teri~l.
.o ~7~S55 ~ ~ * ~ o o ~ ~ O ~ ~ ~ ~ ~
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~ 00 ~ r1 , ,, C~ ~ o ~, 0~ O O O O ~ ~D
,!4 H O ~ 0 h ~N t~ 0 ~ ~ o ;~
CU
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q~
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;81~ ~ qD o ,_ CJ ~ ~ ~ 0 0 o ~ ~-~ c~ ~
o ~ ~
;~ ~ ~
3~ ~ $ ~ R
0 ~
~ rl ~ ~ ~ * *
ss Example 2 Samples of wrapping materials, about 33 cm square ~ere taken and each sample wrapped around & block o~
10 cm x 10 cm ~ 5 cm gr~n m~ple. m e blocks o~ green map~e were cut from a large~ block to mlnimize the variability of moisture content from block to block. Maple was chosen becaus~ o~ its ligh~ uniform colour and high molsture con-tent. The wrapping material~ ~ully enveloped the map~e block~ and were stapled thereto. The wrapped blocks were placed about ~5 cm away ~rom a 250 watt bulb o~ a sunlamp.
Each wrapped block was e~posed to about ten cycles o~ 15 mlnute period~ of heating, with the sunlamp on, ~o}lowed by 60 minute periods o~ coolin~ with the sunlamp of~. After completion Or the ~en cycles each wrapped block was e~posed to six hours of natural sunlight in a w~ndow facing ~outh.
me ~mbient temperature o~ the room wa~ about 10Co Sub-æequent to exposure to the sunlamp and sunlight the blocks of maple were unwrapped and the amount o~ water e~ol~ed and the extent of stainin~ were noted.
Wrapping materials "Clear", "White" and "AL" o~
Example 1 were tested. In addition two ~urther wrapping ma-terials were included for comp~rison purposes. One wrapper~
designated "Black" compr~sed a wo~ren fabric o~ oriented tapes made ~rom a polyethylene having a density of o.960 g/cm3 and con~aining 2 wt.~ carbon black pigment~ in which the ~arp tapes had a width o~ 2.5 mm and a linear den~ity of 889 dtex and the weft tapes a width o~ 4.37 mm and a line~r density o~ 1211 dtex, ~nd which had 3.54 ends/cm and 2.66 picks/cm, eoated on one side wlth a 25 ~m layer o~ polyethylene havlng a den~ity Or 0~923 g/cm3 and containing 2 wt.~ o~ carbon blac~
pigment, and coa~ed on the other slde with a 25 ~m layer of polyethylene ha~ing ~ denslty o~ O.923 g~cm3 ~nd containing 4 wt.~ o~ a blue pigment available ~rom Ampacet Corporation under the trade mark ~MPACET 16431.
The other wrapper, designated ~Paper~Clear~' com-prl~ed one layer o~ 35 lb. kra~t paper~ and a layer of the "Clear" wrapper.
The observations o~ the tests shown in Table II, are a ~urther indication of the e~icacy of the method o~ the present ~nvention.
1~74SS5 O ~ ~ O bt~
~:
0 ~ ~ o ~ ~ o a) o c~ ~ ~ o3 a~
o ~ o O
o o C) ~ ~ ~ o C~
o C
o ~I q~
~ ~ ~q ~ #l k 0 O 5:: G) ~ ,!4 a~
bo ~ ~ o C) ~ h ~ bO C) ~1 4~ 6~ C ~
U~ L) U~
D5~ ~
~ ~ ~ ~1 H ~I
H ~ O O ^ O ^
a~ h h ~ h P
6.1 ~I a) a o ~ $ bQ
~3 0 ~1 h a~
~1 ~ ~ 0 O 3~ ~ ~ h ~1 ~ ~~c1 ~ ~ a ~ ~
rl ~ ~ ~0 oh h 0 0 h p d~ C~
g , O
It .
~7~55 l-13 -~ he light transmittance~ o~ ~amples o~ "Clear", "White", "Paper/Clear"~ "Black" and IIALII wrapplng material~
were measured using a W -visible spectrophotometer.
The re~ults are shown in Table III.
Table III
~rapperTransmittance_in 400-700 nm range Clear 82-86 White 20-50~
Paper/Clear 0%
Bl~ck 0 AL 26-29~
Five ætac~ Or planed and ~iln dried m~xed pine, spruce and ~ir lumber, each about o.6 m x ~.2 m x 2.4 m were packaged in a wrapping matPria}, de~ignated 'tAL-l", 8imilar to the 11Ah11 wrapper of Example 1 except that the scrim con~truc~ion had 3.54 ends/cm and 1.26 pickæ/cm i.e. having a warp crowdednes~ o~ 88% and a we~t crowdedne~s o~ 54~ and the coating wa~ 25 ~m ~hick containing 2.0 wt.~ of ~la~e aluminum. Ten similar stack~ o~ lumber we~e packaged in the '1Clear" wrapping material of Example l. All of the stacks of lumber were wrapped directly a~ter kiln drying.
~he wrapped stacks o~ lumber were le~t in the open for ~our da~s during the month of September and on the ~i~th day all o~ the wrapped stack~ o~ lumber were tr~nsported on an open ~lat bed truc~ a distance o~ 950 km ~rom the Province o~ Quebec~C~n~da, to New York Stat~, U.S,A. Upon reachin~ the de~tination the moisture conden~tion on the lumber wa~ checked b~ hand and ~isually. There was evidence Or ~o~ture condensation pres~nt on ~tacks wrapped in the "Clear" wrapping materlal~ but little or none present on ~tacks wrapped in ths "AL-l" wrapping ~aterial.
Claims (11)
1. A lumber cover having a top panel, two side panels and two end panels, said panels being made of a wrapping material selected from the group consisting of a) a fabric made from woven oriented tapes of polyethylene, said fabric being coated with a layer of polyethylene at least about 15 µm in thickness containing a particulate metallic filler selected from the group consisting of aluminum, brass and bronze, in an amount sufficient to provide a light transmittance through the wrapping material in the 450 to 700 nm wavelength range of less than about 30%, and b) a fabric made from woven oriented tapes of polypropylene, said fabric being coated with a layer of polypropylene at least about 15 µm in thickness containing a particulate metallic filler selected from the group con-sisting of aluminum, brass and bronze, in an amount suf-ficient to provide a light transmittance through the wrap-ping material in the 450 to 700 nm wavelength range of less than about 30%, said panels being of a size such that the cover substantially conforms to a rectangular prismoidal stack of lumber.
2. A lumber cover according to Claim 1 in which the joining edges of the panels are heat sealed.
3. A lumber cover according to Claim 1 in which the joining edges of the panels are sewn.
4. A lumber cover according to Claim 1 wherein the end and top panels are made from a single piece of the wrapping material.
5. A lumber cover according to embodiment (a) of Claim 1 in which the coating of the wrapping material is between about 15 and 50 µm and the particulate metallic filler is aluminum in a concentration between 0.75 and 4.5 wt. % of the coating.
6. A stack of lumber covered on at least its upper, side and end surfaces with a lumber cover having a top panel, two side panels and two end panels, said panels being made of a wrapping material selected from the group consisting of a) a fabric made from woven oriented tapes of polyethylene, said fabric being coated with a layer of poly-ethylene at least about 15 µm in thickness containing a particulate metallic filler selected from the group consist-ing of aluminum, brass and bronze, in an amount sufficient to provide a light transmittance through the wrapping material in the 450 to 700 nm wavelength range of less than about 30%, and b) a fabric made from woven oriented tapes of polypropylene, said fabric being coated with a layer of polypropylene at least about 15 µm in thickness containing a particulate metallic filler selected from the group consist-ing of aluminum, brass and bronze, in an amount sufficient to provide a light transmittance through the wrapping material in the 450 to 700 nm wavelength range of less than about 30%, said panels being of a size such that the cover substantially conforms to a rectangular prismoidal stack of lumber.
7. A covered stack of lumber according to Claim 6 wherein the particulate metallic filler in the lumber cover is aluminum.
8. A covered stack of lumber according to Claim 7 wherein the aluminum is in flake form.
9. A covered stack of lumber according to Claim 6 wherein the lumber cover fabric of woven tapes has a crowd-edness of between about 20% and 70% in the weft direction and between about 30% and 100% in the warp direction.
10. A covered stack of lumber according to Claim 6, 7 or 9 wherein the oriented tapes of the fabric are made from a polyethylene, having a density between 0.940 and 0.970 g/cm3, and the coating is made from a polyethylene having a density between 0.910 and 0.945 g/cm3, said polyethylenes being a homopolymer of ethylene, a copolymer of ethylene and a C3-C8 1-olefin or blends thereof.
11. A covered stack of lumber according to Claim 7 wherein the coating of the wrapping material has a thickness between about 15 µm and 50 µm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000352849A CA1174555A (en) | 1980-05-22 | 1980-05-22 | Method for protecting lumber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000352849A CA1174555A (en) | 1980-05-22 | 1980-05-22 | Method for protecting lumber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174555A true CA1174555A (en) | 1984-09-18 |
Family
ID=4117043
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000352849A Expired CA1174555A (en) | 1980-05-22 | 1980-05-22 | Method for protecting lumber |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1174555A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6367513B1 (en) | 1996-12-11 | 2002-04-09 | Intertape Polymer Group | Pololefin scrims of woven superimposed tapes |
-
1980
- 1980-05-22 CA CA000352849A patent/CA1174555A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6367513B1 (en) | 1996-12-11 | 2002-04-09 | Intertape Polymer Group | Pololefin scrims of woven superimposed tapes |
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