CA2133777A1

CA2133777A1 - Articles formed of multilayered film having antifog properties

Info

Publication number: CA2133777A1
Application number: CA002133777A
Authority: CA
Inventors: Harry Nagata
Original assignee: AT Plastics Inc
Current assignee: AT Plastics Inc
Priority date: 1994-10-06
Filing date: 1994-10-06
Publication date: 1996-04-07
Also published as: AU3560695A; WO1996011108A1

Abstract

Thermoplastic multilayer film for use as greenhouse film and perishable fruits and vegetable product bags comprising a first layer of nylon and at least a second layer comprising a polyolefin. The nylon layer has a surface innermost of the greenhouse when the film is position on the greenhouse, and innermost of the bag. The film in these utilities provides advantageous extended anti-fog properties.

Description

ARTICLES FORMED OF MULTILAYERED FILM
HAVING ANIIFOG PRO~Kll~S

Field of the Invention s This invention relates to multilayered, polyolefin films having an outer layer of nylon and par~cularly to multilayered pol~ ylene films having an outer layer of nylon. The films are of use in gre~nhouee co~.ings and mo~ified atmcs~ e p~ ~ing having improved anti-fog pr~pellies.
ound of the ~nvention A greenhol)~e by its very nature is l_~ui~d to be closed during cold periods to contain the heat to create its growing envir~ nt At high hnmidiq inside the greenhoue~, water con~lene~s on the inside of the gre~nhoue~ roof or cover when the tell~latule of the roof or cover is reduced to the dew point or lower.
One ch~teristi~ of a thermoplastic greenhou~, film in a humid gre~nhou~e envhonl,l~. l is that the water con~ ~- forms on the surface of the film as fine dr~pl~ls. This con~lition is known as "fogging" and creates two basis pl~b'~-m~ for the grower. First, the t~nemiesjon of sunlight~ an e~n~ ;quil~n,enfor plant growth, is reduc~d Se~nd, the fine droplets c~lee~e to form larger dlo~'- e- which fall onto and may d~llage the crop below. The ~l~...age to the crop may be to the extent that the market v lue bae-ed on crop quality is reduoed, and in the case of a ~iqlity crop such as flowers, the d~ gci can render the crop ~ tq~lc One way to o~e~llæ the above plobl~ of ÇOggil~g is to spray the surface of the film ~-l o~d in the ~ ~-o~,~ envin~nnl~nt with a a~ t-n~ ~ which when dry forms a coa~ng which illCl~S the surface tension of the film surface soas to reduce the interfq.~iq~l tension b~o~n the surface and water coll~P-ne-qtP,. The result is that the water vapour c~nd~.-n-c~le wets the film with a clear sheet of wa~er.
The water then runs C~J~II;nIJ~11Y down the curvature of the film, instead of the water droplets "raining" down upon the crop below. The enhqn~d tr.qn~mi~ion of light increases the crop grow~ while pre~ ting crop ~ .aee.

_ ~ 1 3~ SL426 However, one problem çncounte ~d with the aforemP-ntiQnPd spraying of the greenhou~e film is that the sprayed s~bst~nce may itself be harmful to the crop.
~lthough r~l-~ble steps are gPnP~lly taken to protect the crop during the spraying opPr~ti~n, even with the most careful of applir~ti n techniques some crop damage is S ine~ildbly eYreri~pn~
In ^ lditinn~ be~ ~, the coating ~b~.t~nc~ is ~ d as a so1ution and the mi~ing process is PPne~lly critical and l~Uil~S the use of ~ictil1Pd water and/or pH balance control, care by glO..~ must be taken. Further, for sucr~.~rul applir~ti~n the film must be dry, and sunlight to dry ~e coating is ~ ss,~ ~. The grower must not only take great care but must also await the proper weather and time of day to apply the soll ti- n It can thus be seen that an anti-fog system that does not require the labour int~ns;ve S~n~illg of "in-house" film offers an advantage to g~. ~
Another method used to ovc~ ,e the anti-fogging problem involves the il co.~,dtion of surf~Pntc into the plastics matri~ by the " r"l~r~ ~ of thegreenhou~ film wh~ n the ;,ulr~;~.l "blooms" to the inner surface of the greenho~lse covering, i.e., there is a slow release of the s ~. r~ nt to the film surface over time. In use, the su- r;.. ~.-t is abs~llæd at the film surface into the water condPneqt~P and effects a l~lu~:~;nl- in water surface tPnston. This causes the water to sheet and prevent the forlnqti~n of droplets. Unfollu-ldtel~, the effiri~Pnf,y of the anti-fog plo~~ s of the film drops off over time.
Thus, there is a need for a film having an ~- h~ Pd err~live greenhouse, antifog p~pc~l~ l;r~ over that given by co-l,lllc.~;ally available greenhouee films.
For related reasons there is also a need for an improved film when used as known in the art as "lU~lifiPd ~I~..os~.h~ P- ~;~&i~Pn. Such p~^~ging ismade of a Ih-....o~l~el;r mqtPriql in the form of s~hP-te, bags, sacks and the lilce for cqn~ining food pr~lu~ such as meat, ~egetab1es and fresh fruits.
W}lile rno~ifiPd ~ r~jr~ inrllldes Val~;UUlll P~d~
such as for sliced meat pollions, a major outlet at the retail level is for fresh veg~t~ble salad mix bags and fresh veget~hle portion packs. The bags or packs &Pnerqlly have ap~llul~s to allow for air and carbon dioxide pe~ qn~ ~ or c...i~, on, by having ~ P~l hole siæs or po~s;l)u 3 ~133777 SL426 One of the drawbacks of clear film p~l ~ing for the above use is that the film of the bag 'fogs-up' in a cool storage area such as in a cooled retail display shelf or the like in a retail outlet such as a ~ 1 This Çogging hinders the desired good visibility of the food c~l-tr .l~i As in the case of some greçnhou~P, film formulAtion~ mPntinnP~ hereinabove, surf~tAntc have been incol~-ated into the l,e."lùplastic matrix to reduce the fogging. ~lthough anti-fogging long life l~uile.llell~ of food pA~a~ g iS not nc~c .~ as in the case of greenho~e film, release of sl~rf~t~nt to the surface or skin of the food is not d~pc~ le- Accor~ingly, there is a need for an improved anti-fog film and, particularly, for such a film that does not release chemi~A~ls to C~UI-A~;n~e foods.

Sun"ll~ of the Invention It is an object of the present invention to provide a greenhouse having a roof covering of a film having anti-fog p~,Le~ of ~ ded effectiveness.
It is a further object of the invention to provide mo lifipd ~I...osphe~e pac~ing for fresh food p~luce formed of a i,--- r~ -free anti-fog film.
These and other objects of the present invention will be seen from a reading of this spe~ifi~tinn as a whole.
Accordingly, the invention provides in one aspect an illl~JlU~
greenholl~, ACc~ ~bly c~ ;c;l~g in co--~h;.-A~ n greenhouse cover support means and a multilayered Ih~ opl~ct;e film suppoll~d by said cover support means, said film having a first layer i-~nc...-o~t of the ACS~mbly and at least a second layer, the illlp~e.llent compricing said first layer is a nylon and said second layer co~ .;~s a polyolefin.
By the term "nylon" as used in this spe~ifil~tinr~ is meant melt-~luc~ lP tl,l ....opl~cl;c polyamides whose chain ;~u~lw~, f~lures l~ g amide groups, such as, for ~ ~le, ~IlOl~ûuS nylon, nylon-6,6 (poly~ ylene ~i~mi~e)~ nylons-6,9, -6,10 and -6,12, nylon 6 (pol~cdpr~"lide), nylon 11, nylon12, polymers, copolymers and blends thereof.
It is known that nylons absorb IllOiS~Ul~ from their i".."PAi~
env~mlle~lt to ~e. tually reach a level that is in equilibrium with the relative 4 ~ 1 3 3 7 7 7 SL426 hl.mi-lity of the ~nl~n~l~hPre. It is known also that moisture has a plq~tici7ing effect on nylons that inc~ses flexibility and impact rÇsict-qnce It will be app~ nt that in one aspect the invention resides in the discovery that a nylon layer providing the inn~ ,o~l surface of the roof covering of a greenhouse provides Qqti~fq~tory anti-fog ch-q-~ctç~i~ti~-s over an un~ ected bçnPfi~ iql period of time. Thus, the nature of the second and, optionally, other layers of the multilayer film of use in the prq-~tice of the invention may be suitably sPl~ct~d by the skilled artisa-n based on the usual desired pf~p~,Les such as weight, e. se of mqmlfq.~ture, durability, rçci~t-qnc~ to s~nlight and the like. It will be, thus, clear that the choice of olefinic mqtPriql of such ~.bo~i-~ate layers is not crucial to this invention and resides within the skill in the art.
~,f~bly, the s. bo~ e layer is formed of at least one polyolefin.
By the term ~polyolefin" as used in this ~ifirqtion and claims is meant the polyethylene, polyp~opJlene and pol~u~ pne family of olefine polymers and copolymers. As examples, high density, low density and linear low density polyethylenes and 1,2 - poly-l,u~ PnPs may be mPnti-nP~ The term ~poly~ ylene"
includes ethylene homopolymers, and copolymers of, such as vinyl ~c~PtP" acrylicacid, methyl Illeta.~ylale, butene, n-h~P~PnP~ 4-methyl-1-p~ ~t~ne and octene polymers with ethylene and blends thereof.
The multilayered film of use in the pl~^tir~ of the invention may compri~e (a) a plurality of distinct layers c~ r~ ed as a plurality of distinct plies, (b) a l~ e cQmrri~in~ at least two distinct films or plies adhered to each other, dil~tly, or by means of an adhesive, (c) a co ~ luded film produced by the self-q.~hPc;on of two or more films to each otha under hot process c n~iti~n~ or (d) a co-oriented film, l~ te or ply made by the cold drawing of a plurality of p~ films, Q;mUl~ ously in such dose contact 1~t th- r that under the d,~wing step at the dl~-ng te~ u-~ the films b~---e i~.t;..~l. ly ~c~ ~d and unified into a single reS~Jlt~nt film or ply while each undivided film is being uni-axially o. ;Pn~*~
The co~ uded film of use in the invention may comprise two or more layers provided that a nylon layer comrri~es one outer laya. In the case of a typical three layer coextrusion film the layers are nylon, a tie layer, and a polyolefinic plastic m~tPni~l The tie layer provides the bond strength ~l~n the nylon and the polyolefin layers. By use of additives in the polyolefin layer, it is also possible in the n~tive to bond the polyolefin to nylon will,oul the use of a special tie layer.
C~ALlusion of films may be acco...l lichPd by the blown tubular film method or the sheet method, both of which are collllllonly used in in.lu~
S The tie layer may comprise those polymers well-known to industry for bonding olefinic plastic mqtPri~l~ and nylon, for c.a ~'~, Prim~c~orn' from Dow Chemir~l~, Plexar~ from QIJ~n~ll.ll ChP-mi~ql~, Surlyn~ from DuPont and Attane~
from Dow ChPmi~l The layers of nylon, tie and poly~'^rin may be, plef~l~bly, further stabilized for multiyear service life in a greenhouse e.. ~dron.. ~.-t Stabili7~tion additives, incl~lde, for ~.a ,le, ~ntirsi-l~nt~, UV stabilizers, UV abs~ and ch~ ;ng agents in the qu~ntitips ~uilèd for their spe~ific appli~ ~tion.
In ~d~ u~ the coextruded film may contain additives to give light diffusion, ~lt~r~ti~n of sunlight ~ u~ infra-red energy conservation, and barrier prop~,.hes.
~f~,~ly, the film co- -l.. ;~,s a nylon having a ,...~ g point (Tg) of b~t~. 130C, p~fe,~able 200-230C.
The nylon layer after equilibration with water in a humid ~tmoi"Jhc-e to be~l,le so called "wettedn, pre~bly, has a surface tension of greater than 65dynes/cm and, morepl~f~,~bly, b~t~.~cn 70-75 dynes/cm.
A typical multilayered film of use in the invention is a c~hu~ion of:
Nylon layer EMS grade XE 3303 1 mil Tie layer P~ . 1 mil Olefinic layer LLDPE 2.5 mil The multilayered films as ~les~rihed aÇ~,r~id may be readily made by ~o,~id pi~ces~s known in the art")~f~ably by blown film ~AIl~sion. Film widths range, typically, from lm to 15m. 3- and 5-layerêd co~.~l.uded films of a nylon outer layer with layers of LDPE, LLDPE or EVA copol~",~ blends are most plef~.lèd.
The multilayered film is imt~ll~ and laid to cover the covering ~ul)polls of a gretnhou~e structure as is convention~l in the art, but with the nylon surface on the inside of the gre~nhol~. The hllmitlity within the gre~nhou~e ~ndçn~Ps on the nylon surface to form a clear sheet of co~den~tp~ Freshly in~t~lled - ~ - 6 2133777 SL426 film takes less than 24 hours to equilibrate with the humid gre~-nhouse qtmo~ph~ . e and b~o.~ wetted.
The antifog action of the nylon film is very long lasting as to be ~med almost pe~ ...qnel~l in its anlifogging effect, since there are no s-~ r; - l~..h or sylaytd ~qting~ to be ble-q~ ~ away.
Pq~ing compri~ing film of use in the present invention mqnuf~ red in the form of sheets, rolls, bags, sachets and the like may .lso be made by con~nt;on-q-l plwesses known in the art. The ~ ing is, gene~ally, provided to the food pr~ccssor for the pa~L;~ of the ve~et-q-hle, fruit or meat produce carried out conventionqlly by hand or m~hine. The ~ ~ produce may be then, optionally, cooled or ref ig~t~ prior to distribution to retailers.
Accordingly, in a further aspect the invention provides a p~r~
pe-ri~h-qhle foo~sh-ff compricing in co",bindlion a ~l.~ing article as h~ nbefole defined cQ~ ;ning the foo~stuff.
Brief Dc3eli~tion of the Drawin~

In order that the invention may be better unde~tood p,erelled emho~iment~ will now be de~rihe~ by way of e~qmr'~ only with reference to the acco"~pa"yin& Pl~qmF1es and d awil gs wh~
Fig. 1 ~e~ scn~ a pc ~ e view of an unrolled, unfolded film position~ on a gre~nho-lse accolding to the invention; and Fig. 2 r~ sen~ a ~;ti.~e view of a p~^~ge cQn~-;ninP a foo~ rraceor~ g to the invention.
Detailed D~,i~)tion of F~fe~l~d ~u~ nts of the Invention ~r~lc~ot~ antifog tests ~imlll~t1~ multiyear C4..~...e-~,;al usage have shown that f~mbodiments of multilayered nylon films of use in the pr?^tiee of the present invention ~IÇol~ned both s~ r~e~ ;ly and conl;~ ously long after a co..~ ;dlly available antifog gre~nhouse film had bæo~..e "foggedn.

- 7 - ~1337 7 7 SL426 E~ ple 1 Accel~aled Test for Simulated T~n~evity of Antif~ Pe.roi"lance S Spff~ ns of l~ ~nt nylon films (EMS - ~mPrie~n Grilon Inc, Sumter, S.C. U.S.A) (304 mm X 600 mm) were ~rrængP~d to form a plastic in~
roof of a tent-like humitlity box en~lo~ing a water bath ,..~inti..nP~l at 60C to provide a humid ~...os.~he~ at a ~ ..~;~ e of about 38C. The outer layer of the film was to the ~ k~.~ at an a,llb cnt t~ ..lY AIV~ of about 22C. The s~ -r~-films were n.oui~t~ in an in-~.lin~d position such that condencal~ conl;.-~ lly ran down the length of the inner surface of the .s~-;...~n films and washed their ~--- r~ S The nc were obse~ed by visible in~tirn for an ~ to be made of the longevity of the anti-rogging ch~ ties RP~ULTS
Length of Antifog ~.fol,l-ance Sample Grade Co.l-po~ilion (l~lfonth~) or~in~l CR6~RSP CoPA 6/6.9 5 Folie 2 blend 75 % F34/25 æ CR9 11 +
Folie 3 blend 85 % F34/15 % CP62BS 11 +
Folie4 blend 85% F34/15% X~222 11+
Folie S XE 3314 MedVis PA6, = Nu(~l~t~ F34 11+
Folie 6 XE 3398 XE 3222 + arnorph CoPA (G21) 11 +
Folie 7 FE 4122 PA6 + ~llolt)l~ous CoPA 11+
~d-liti~n~l XE 3303 CoPA 6.6/6.10 11+
93-46 blend 85% CF62BSE + 15% G21 1.5 commercial an~fog greenhouse film;
AT Plastics Dura FilmR 2 AF s.J~ ct~nl AF 1.5 The results show that cull~ ~ co"""c.c;al grades of filmable nylon ul~ed well in showing ~";~r;~ antifog prop~llies for up to the lire~."e of the test, i.e. 11 months, in conl~ to the control co","-.,.cial greenhouse film's result of llt2 m~th~

`_ -8- 2133777 SL426 The effect of moisture on nylon is also benefi~ when the nylon is used in articles of the invention, e.g. greenhou~e or p~ ~ing film by making thenylon layer less brittle! A dry and "wetted" five-layered sample COI..~. ;~nn for the sample comrri~i~ FE 4122 is given below, as Y:
S Y. Layer 1. Blend LDPEILLDPE (100 ~m) 2. Tie (5 ~m) 3. FE4122 (20 ~m) 4. Tie (5 ~m) 5. PEA122 (20 ~m) Physical }?~ Lies Units Dry as is Wetted Ftnw-do.r tear, MD N 1.74 3.74 TD N 10.6 9.98 Tensile plop~.lies MD:
Yield strength MPa 20.0 15.9 Break ~ lh MPa 33.0 32.4 Fl~-ng~tir n % 326 362 Tensile pl~ ies TD:
Yield ~en~;lh MPa 20.8 16.6 Break ~ h MPa 24.7 17.7 p~ g~ti~.n % 307 263 Moi~ re loss, 48h % 1.2 Light Tr~n~mi~ n % 91.7 91.7 With l~fel~nce now to Fig. 1, wl~ a greenhouse ~ ..bly shown gen~.~lly as 10, has a plurality of roof support n..~ x~ 5 12 and side support n.~-. be~ 5 14 to which is held a covering film 16. Film 16 is ~lr~l~d from the five-layered films of the following cori,l-uction:

9 ~133777 SL426 1. Order of Material LDPE 85X F3A 85X F3A
~ HV ~ RV

Thickness 100 ~ 5~ 20~ 5a 20 2. Order of Msterial LDPE

LLDEP
Thickness 100 ~ 5~ 20~ 5~ 20 3. Order of Materia~ LDPE

LLDPE
Thickness 100 ~ 5~ 20~ 5~ 20 4. Order of ~ateris~ LDEP
~ HVXE 3314 HVXE 3314 LLDPE
Thickness 100 ~ 5~ 20~ 5~ 20 wl,e.~in HV is a tie layer of ethylene/vinyl acetate copolymer. These films are made on a commercial five-layer co e~hu~;on line.
Fig. 2 shows generally as 20 a ~ ,.."opl~t;e L~gi~p article c~lAi~ing a ppri~h~hle fOO.~ rr, such as a fruit or ve~Pt^t~lP- (not shown) formed of the five-layered film 22 ~lc~-.il~d h~inbero.~ under sample Y. Bag 20 has a plurality of breath holes 24 and co~ c a plurality of apples 26.
The nylon thc~...op~ ie ela~h,l~ have the following plo~.li~c.
Grilon XE3303 (Nylon 6.6/6.10):
TEST
PROP~K11kS M~l~lOD UNITS VALUES
General Melting Point DSC F/C 392/200 Specific Gravity ASTM D792 -- 1.09 Melt Flow Inde~ DIN 53735 ml/10 min. 60 (275C/10 kg) dry 24 hour H2O
Al ~ ASTM D570 % 1.16 ~Im 1.. . tiw I r ~ a on a 50 pn film sample) 2 1;. ~ Ijty 73F(23C)150% RH DIN 53380 cm3/ '-d~b- 55 73F(23C)/100% RH 75 CO
73F(23C)/50% RH DIN 53380 cm3/m2 d bar 185 N2 ~ ' lity 73F(23C)/50% RH DIN 53380 cm3/ ~ d~b 12 Water Vapor r~ , DIN 53122g/m2 d 14 900 Cycb Gelbo Fle~ Tester EMS holes/m2 190 -- 10 -- 3 3 ~ 7 7 SI~T26 Puncture Work DIN 53373 Nm (cond.) 0.5 Ql ~ EMS % 30 Gloss (60) DIN 67530 120 S r~ , ti~ PrY-As -Molded C ' - ' Tensile Strength ASTM D638 psi (MPa) 9,000(62) 3,600 (25) pl _ - ~ Yield ASTM D638 % 5 25 p1- g ~ Breal~ ASTM D638 % 100 300 Fle~ural Strength ASTM D790 psi (MPa) 12,000 3,000(21) Fle~cural Modulus ASTM D790 psi (MPa) 266,000 60,000(414) TT ~. Shore D D Scale 78 68 Izod Impact Strength ASTM D256 R-lb/ina/m) 1.01(59) Grilon XE3222 (NYlon 6/6.9):
TEST
PROP~KllkS METHOD ~lNlTS VALUES
G~
Mdting Point DSC F/C 396/202 Specific Gravity ASTM D792 -- 1.11 Melt Flow Inde~ DIN 53735 ml/10 min. 140 (275C/10 kg) dry 24 hour H2O
~ i ASTM D570 % 2.20 ~lm l,~, L~.s ( e ~ on a SO ~n film sample) 2 F ' lity 73F(23C)/50% RH DIN 53380 '/ ~-d ~- 35 73F(23C)/100% RH 100 CO2 p~~ ~~' ' ty 73F(23C)/50% RH DIN 53380 cm3/~-d ~ 70 N2 ~ ;ty 73F(23C)/50% RH DIN 53380 cm3/m2 d bar 14 Water Vapor r~ DIN 53122 g/m2 d 20 900 Cycb Gelbo Fle~c Tester EMS holes/m2 400 Puncture Work DIN 53373 Nm (cond.) 2.5 Q~ EMS X 25 Gloss (60) DIN 67530 100 r~ s DrY-As -Molded C/ ~
Tensile Strength ASTM D638 psi (MPa) 9,400(65) 4,100 (28) p~ Yield ASTM D638 % 10 25 P1- 9 e~ Br~ A~r~ D638 % 270 300 Fle~cural Strength ASTM D790 psi (MPa) 13,100 3,000(21) (90) Fle~ural Modulus ASTM D790 psi (MPa) 304,000 65,000(449) (2098) T~- . - Shore D D-Scale 76 69 Izod Impllct Strength ASTM D256 R-lb/ina/m) .08(43) N.B.

Grilon G21 (Amphous nYlon co~l~
TEST
PRO~Kll~ METHOD UNITS VALUES
Gend S Glass Transition Temp DSC F/C 257/125 Specific Gravity ASTM D792 -- 1.18 r' ~ ASTM D570 %
24 hour ~ 1.29 Melt Plow Inde~c DIN 53735 ml/10 min.(dr,y) (275C/10 kg) 90 Inde~c DIN 53491 -- 1.58 Light T - ASTM D1003 % 91 Heat ne"- ~i T; e 66 psi (455 kpa) ASTM D648 F/C 244/118 264 psi (1820 kPa) ASTM D648 F/C 223/106 Me~anical Tensi1e Strength ASTM D638 psi (MPa) 10,400(72) pl ~ - ~ Break ASTM D638 % 15 Fle~cural Strength ASTM D790 psi (MPa) 17,200(119) Fle~cural Modulus ASTM D790 psi (MPa) 416,000 (2870) Izod Impact Strength ASTM D256 ft-lb/in Notched . (J/m) 1.0 (53) l' 3 Shore D-Scale 80 Flm l ~ measured on a so micron film sample) O p~ y 73F(23C)/50% RH DIN 53380 cm3/ '-d 1 30 73F(23C)/100% RH 8 CO2 ~
73F(23C)/50% RH DIN 53380 cm3/m2 d bar 75 N2 ~ ' I;~y 73F(23C)/50% RH DIN 53380 cm3/m2 d bar 10 Water Vapor Pt ' ' ~i DIN53122 glm2 d 7 Gloss (60) DIN 67530 140 Grilon F34 Natural 6368 (NYlon 6l:
TEST
PRCir~Kll~S MF~OD UNITS VALUES
General Melting Point DSC F/C 430/220 Specific Graviq ASTM D792 -- 1.14 45 '= ~ A1 , - ASTM D570 %
24 hr. ~ ~ 230 lo ~ir 73 F(23 C)/SO æ RH 2-3 Ia Water 73F/23C ~ 10 Fllnl.. ti~
2 P~ V DIN 53380 cm3/mZ-d-bar 23C/0% RH 25 23C/85 % RH 100 CO2 p~ y 23C/0% RH DIN 53380 cm3/ ~-d~ 65 N p~ ;q 23C/0% RH DIN 53380 cm3/ 7.d~-- 10 `~ - 12- ~133777 SL426 Water Vapor p~ -' 'l;t,y DIN 53122 glm2 .d 20 Gloss (60) DIN 67530 100 Dry-As r~- t ~ -Molded C~
Tensile Strength ASTM D638 p6i (MPa) 10,600(73) 5,500(38) Fl " d Yield 5 20 Fl - at Break ASTM D638 % 265 315 Fle~cural Strength ASTM D790 psi (MPa) 16,000(110)4,500(31) Fle~cural Modulus ASTM D790 10~si (MPa) 35(2400) 8(56Q) Izod Impact Strength ASTM D256 ft-lb/in Notched alm) 1.9 (1.01) N.B.
Charpy Impact Strength ASTM D256 ft-lb/in2 Notched 73P/34C ~lm2) 11(5) 42(20) -40F/C 4(2) 11(5) TT Shore D-Scale 80 78 Grilon CP62BSE (Nylon 6/6.9):
TEST
PROP~K l lkS METHOD UNlTS VALUES
G~
Melting Point DSC P/C 273/134 Specific Gravity ASTM D792 -- 1.09 Melt Plow Inde~c DIN 53735 ml/10 min. 40 (190C/10 kg) dry 24 hour H2O
~l p" ASTM D570 % 2.53 Flm l .. ~ ~;w ~ ~ ~ on a 50 pm f~n s~mple) 2 ~ ' 1ity DIN 53380 cm3/m2-d-bar 73F(23C.)/50% RH 45 73P(23C)/100% RH 200 35 CO2 p~ -lity DIN 53380 cm3/ 7-d l-- - 125 73F(23C)/50% RH
N ,~ Y DIN 53380 cm3/~ ~7-d t 10 73P(23C)/50% RH
Water Vapor DIN 53122 g/m2 d 20 40 r~ ity 900 Cycle Gelbo EMS holes/m2 600 Ple~ Tester Puncture Work DIN 53373 Nm (cond.) 2 EMS 9~ 40 45 Gloss (60) DIN 67530 120 r~ ' .. ~ I;w Dn-As -Molded C
Tensile Strengtll ASTM D638 psi (MPa) 5,900(41) 3,700(26) Pl _ ~ Yield ASTM D638 % 10 20 P~- _ ' OE Break ASTM D638 % >250 330 Fle~ural Strength ASTM D790 psi (MPa) 2,500(17) 2,000(14) Fle~ural Modulus ASTM D790 psi (MPa) 120,000 75,000(520) (828) TT- ' Shore D-Scale 72 59 Izod Impact Strength ASTM D526 ft-lb/in a/m) N.B. N.B.

`_ - 13- 2133777 SL426 Grilon CR9 (Nylon 6/12):
PROPERTY METHOD UNIT VALUE
G~
Melt Point DSC C 200 Specific Gmvity ASTM D792 -- 1.10 Melt Flow Inde~ DIN 53735 ml/10 min. 200 (275C/10 kg) dq 24 hour H20 .~ ASTM D570 % 2.5 Fllm l .. . ti~ ( ~ d on a 50 pn film sample) 2 p~ ' lity DIN 53380 cm3/m2-d-bar 23C/50% RH 55 23C/100% RH 100 C2 ~ ' 1ity DIN 53380 cm3/m2 d-bar 170 23C/50% RH
N F~ ~ ' lity DIN 53380 cm3/m2 d bar 13 23C/50% RH
Water Vapor DIN 53122 g/m2 d 15 ~ ~ ~
900 Cycle Gelbo EMS holes/m2 800 Fle~ Tester Puncture Wo* DIN 53373 Nm cond. 3 ~ EMS 30 Gloss (60) DIN 67530 140 r~
Tensile Strength ~at Yield ASTM D638 psi 5,800 Tensile Strength e~
Break ASTM D638 psi 7,100 Fl - ~ Yield ASTM D638 % 20 Fl ~ '- ~ Break ASTM D638 % >300 Fle~ural Strength ASTM D790 psi 11,000 Fle~ural Modulus ASTM D790 psi 240,000 T' ' - Shore D -- 80 Izod Impact Strength ASTM D526 R Ib./in. 1.9 While certain p~ ~ embo~ of the invention have been i111)st~t~
and described for pUl~)OSeS of the present ~ osl~re~ nu~ us ch~ in the arr~n~e-..en~ and consh--clion of elf--.~-n~ thereof may be made by those slcilled in the art which ch~r~e.~s are e~ ~d within the scope and spirit of the present invention as defined by the al pc d~ claims.

Claims

1. An improved greenhouse assembly comprising in combination greenhouse cover support means and a multilayered thermoplastic film supported by said cover support means, said film having a first layer innermost of the assembly and at least a second layer, the improvement comprising said first layer is a nylon and said second layer comprises a polyolefin.

2. An assembly as claimed in claim 1 wherein said nylon has a surface tension greater than 65 dynes/cm.

3. An assembly as claimed in claim 2 wherein said nylon has a surface tension of between 70-75 dynes/cm.

4. An assembly as claimed in claim 1 wherein in said nylon is selected from nylon-6,6; nylon-6, nylon-6,9 and nylon-6,10.

5. An assembly as claimed in claim 1 wherein said polyolefin is a polyethylene polymer, EVA copolymer, or 1,2-polybutadiene, or blends thereof.

6. An assembly as claimed in claim 5 wherein said polyethylene is selected from LDPE, LLDPE and HDPE.

7. A greenhouse film of such dimension as to cover a greenhouse wherein said film is as defined in any one of claims 1 - 6.

8. A produce bag, package, sachet and the like formed of a thermoplastic multilayered film having a first layer innermost of the bag operably in contact with said produce and at least a second layer, the improvement comprising said first layer is a nylon and said second layer comprises a polyolefin.

9. A produce bag as claimed in claim 8 wherein said nylon has a surface tension greater than 65 dynes/cm.

10. A produce bag as claimed in claim 9 wherein said nylon has a surface tension of between 70-75 dynes/cm.

11. A produce bag as claimed in claim 8 wherein said nylon is selected from nylon-6,6; nylon-6, nylon-6,9 and nylon-6,10.

12. A produce bag as claimed in claim 8 wherein said polyolefin is a polyethylene polymer, EVA copolymer or 1,2-polybutadiene or blends thereof.

13. A produce bag as claimed in claim 12 wherein said polyethylene is selected from LDPE, LLDPE and HDPE.

14. A produce bag as claimed in any one of claims 8 - 13 further comprising said produce contained within said bag.