CA2013742A1 - Semi-rigid, heat-sealable laminates with permanent antistatic characteristics - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A semi-rigid, heat-sealable laminate with permanent antistatic characteristics comprising a semi-rigid packaging material having a coat-ing of heat-sealable antistatic plastic. The antistatic plastic is a film of a modified acid copolymer. The modified acid copolymer is selected from (I) a mixture of (A) a polymer containing carboxylic acid moieties and (B) an antistatically effective amount of a guaternary amine, or (II) the acid/base reaction product of (A) a polymer containing carboxylic acid moieties and (C) an antistatically effective amount of an organic or inor-ganic base.

5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

Description

- - -SEMI-RIGID HEAT-SEALABLE L_AMINATES WITH
PERMANENT ANTISTATIC CHARACTERISTICS

The present invention involves antistatic packaging laminates and methods of producing such laminates, and more particularly a packaging lsminate comprising a semi-rigid substrate sheet of packaging material such as cardboard which is coated with a layer of heat-sealable, antistat-ic plastic. The structure provides both mechanical support for a static-sensitive item to be packaged and a permanent antistatic shield to protect the item from static build-up while it is being packaged, and during ship-ment. Typical static sensitive items to be packaged are electronic cir-cuit boards. Furthermore, the heat-sealable plastic coating permits a flexible antistatic skin film to be hsat sealed to the laminate if so desired, 50 that it may be employed in skin-packaging systems. A problem in the past has been that coated cardboard used during skin packaging was not permanently antistatic.

This problem is solved by the present invention, which relates to a semi-rigid substrate sheet of packaging material, such as cardboard or fiber board, having a coating of heat-sealable permanently antistatic plastic. The coating of heat-sealable antistatic plastic comprises a layer of a modified acid copolymer. The "modified acid copolymer" is selected from:

~I) a mixture of ~A) a polymer containing carboxylic acid ieties and (B) an antistatically effective amount of a quaternary amine; or 5/891227.3/SPECFLDR/03/23/90/10:36:50 AM

r~ ~ ~
(rI) the acid base reaction product of (A) a polymer containing carboxylic acid moieties and (C) an antistaticallY effective amount o~ an organic or inorganic base.

The coating layer h~s penmanent, non-bleeding antistatic characteristics.
~y "permanent, non-bleeding" antistatic characteristics is meant that even after a 24-hour water shower, and/or after 12 day hot oven aging at about 70C, the coating layer exhibits a static decay time (hereinafter abbrevi-ated as SDT) under about 3000 milllseconds (hereinafter abbreviated as ms) when the SDT test using 5000 volts direct current (hereinafter abbreviated as Vdc) is performed as per Federal Test Method 101c, Method 4046.1, i.e.
the antistatic property is not washed out by the shower andtor is not loæt after 12 days in a hot (approximately 70C) oven. The Federal Test Method requires that the SDT test be performed in a "dry" atmosphere, i.e. about 15% relative humidity or less. A problem with prior antistatic coatings is they need a typical ambient atmosphere of 40 to 50% ~i to work, and they behave as insulators under "dry" conditions of 15~ RH or less. In a preferred embodiment, the present coating layer exhibits a low propensity toward triboelectric charge generation.

~ACXGROUND OF THE INVENTION

When two surfaces are brought in contact with each other, a transfer of electrons may occur resulting in a residual static electrical charge when the surfaces are separated. This phenomenon is known as tribo-electricity. A common example is the static a person feels after shuf-fling along a carpet and then touching a metal door knob. If the surface is composed of a material that is a conductor, the electrons will dissi-pate quickly thereby eliminating the excess charge. On the other hand, if the surface is composed of a material that is an insulator (a dielectric), the surface charge takes much longer to dissipate. Thermoplastic polymers are typically excellent insulators and thus are unsatisfactory for uses requiring a nature that will dissipate charges. As the polymers accumu-late high charges promoting an attraction for dust and dirt, they can discharge to any lower potential body with which they come in contact.
About 3000 to 25,000 volts or more can easily sit on the polymer surface.
5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

If tllLS discharges to a circuit board wrapped with the polymeric plastic, such a high voltage will ruin the circuit board. To modify a polymer to have antistatic characteristics and dissipate charges, the conductivity might: be increased which in turn causes an increase in the rate oE static dissipation, thereby reducing ~linging effect, eliminating harmful static discharge, and preventing accumulation of dust.

It is well known that static charge can be reduced by increas-ing the moisture content of the atmosphere, and thus the approach in the past has been to use an antistatic agent which will modify the inherently dielectric polymer to Lmpart hydrophilic properties to it by providing migrating agents with functional groups that attract moisture to it.
This migration is colloquially referred to in the art of a~tistatic poly-mer technology as a "blooming" or "bleeding" effect. Such films can overbloom and lose their antistatic character if subjected to a 24 hour water shower or a prolonged heat exposure (12 days in a 70C oven).

Of relevance is the ~nglish translation of Japanese Kokai ~Pub-lished Application) No. 61-2703, inventors Inazawa et al, assignors to Showa Denko, published January 8, 1986 (filed June 15, 1984, filing no.
59-121854). This states on page 1 that they claim an electroconductive resin, made of a copolymer of ethylene and unsaturated carboxylic acid, where a part or a whole of said carboxylic acid forms a salt with a nitro-gen-containing compound chosen from a group comprising amine compounds and quaternary ammonium salts and the content of said nitrogen-containing compound is at least 1.3 mmol/g of the resin.

Many patents show quaternary amines (also referred to as quaternary ammonium compounds or salts) as antistatic agents. Examples are US Patent 3,324,091 to Sauides, US Patents 3,445,440, and 3,517,045 both to Susi and Arthen, US Patent 3,894,077 to ~orikawa et al, US Patent 4,104,175 to Martinsson et al, US Patent 4,268,583 and T961009 both to Hendy, and US Patent 4,605,684 to Pcolinsky.

Also of interest is Japanese Published Patent Application Kokai No. S9-47243, Ito et al, assignors to Mitsui (published March 16, 1984) which shows an electrically conductive resin composition comprising 5/891227.3tSPECFLDR/01/10/90/02:59:47 PM

7 ~ ~
ethylene/alpha,be~a unsaturated carboxylic acid copolymer and a tertiary alkanolamine.

Antistatic skin packaging is dlsclosed in us Patents 4,707,~14;
4,677,809; 4,623,564; 4,5S4,210; and 4,590,741 to Long and Maciocia, as-slgnors to General Dynamics. All of these show tertiary animal Eatty amine~s as the antistat~c agent.

Al~o, U.S. Patents 4,610,353; 4,685,563; 4,241,829; 4,480,747;
4,4a2,048; and 4,71Z,674, all show coating or painting such as by spray-ing, brushlng or rolling, a conductive carbon coating onto cardboard.

More particularly, US Patent 3,933,779 issued January 20, 1976 to Baron et al assignors to Fine Organics discloses an antistatic polymer blend comprising a synthetic polymer and an antistatically effective amount of a compound of the formula:

HOCH7CH;~ ' CH,-N-R CH I 0 SO, HOCH;.CH, whereln R is alkyl Oe 4 to 18 carbon atoms unsubstituted or sub6tituted by halo or aryl.

At pages 18 and 19 of published European Patent Application 021931S Mott assignor to Dow, date of publication April 22, 1987, (counter-part of US Patent 4,756,414, issued July 12, 1988) is a passage stating that their preferred antistatic material is an acrylate monomer-oligomer mixture containing an alkylether triethyl ammonium sulfate~available from Metallized Products under the trade-name Staticure, which material is curable by exposure to an electron beam to a permanent, non-bleeding coat-ing which is not dependent on humidity for its antistatic effect. The pa~sage in EP 0219315 goes on to say that further details concerning this material appear in British Patent Application No. Z, 156,362 published October 9, 1985.

British Patent Application No . 2,156,362 is the counterpart of US Patent 4,623,594 issued November 18, 1986 to Keough assignor to Metallized Products. US Patent 4,623,594 claims:

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~3 ~
1. An antistatic laminate, both sides of which have antistatic characteristi~s, comprising:

(A) a substrate sheet;
(a) a continuous coating on one side of said substrate sheet, said continuous coating comprising the electron radiation cured product of:
~1) an electron beam curable prepolymer; and ~2) an effective amount of a saturated quaternary ammonium compound antistatic agent soluble in said prepolymer the product being a reaction product of the prepolymer and the ammonium compound converted into a substantially solid product.

2. The antistatic laminate of claim 1 wherein said quaternary ammonium compound is a trialkYlalkYle-therammonium salt. EEmphasis supplied.l The laboratory examples oE US Patent 4,623,594 show that the particular trialkyl alkylether ammonium salt employed was Emerstat 6660 from Emery Industries. Page 52 of a catalog entitled "Miscellaneous Surfactants"
describes Emerstat 6660 as a 100~ actlve llquld cationic compound which offers high performance antistatic capacity, but page 52 does not give any generic chemlcal formula. It is believed that Emerstat 6660 is a dlethoxylated alkyl ammonium salt of the formula ~A)~A')NltCH~CH~O)nHI2 A'OSO3- which is further described below.

Of gensral interest is US Patent 4,678,836 (July 7, 1987) HcKinney et al assignors to Dow Chemical. It shows blends of linear low density polyethylene (LLDPE) and ethylene-acrylic acid (EAA). Also o~
general interest is US Patent 3,799,901, March 26, 1974, McCann et al, assignors to Dow Chemical. It shows the preparation of lataxes by direct dispersion of acidic organic polymers into aqueous alkaline media.

..

S/891227.3/SPECFLDR/01/10/90/02:S9:47 PM

3 7 ~ ~

BRIEF DESCRIPTIO~I OF THE: DRA~'IINGS

FIG. 1 is an enlarged partial side ssction showing the structure of the packaging la~inate according to a preferred embodiment of the present invention.

FIG. 2 is a perspective view of a sheet of packaging laminate according to a preferred embodiment of the present invention which has a shape suitable for forming an anti-static package.

FIG. 3 is a perspective view of an anti-static package constructed from a sheet of packaging laminate according to the invention which has the form illustrated in FIG. l.

FIG. 4 is a perspective view of an anti-static package which is constructed from a support base of laminate according to a preferred embodiment of the present invention and an anti-static skin-packaging material which encloses it.

OBJECT OF THE INVENTION

A need exists for a semi-rigid laminate which is suitable for packaging static-sensitive items which combines permanent protection of the item from exposure to electrostatic charge, mechanical support of the item while it i8 being packaged and handled in packaged form, and adaptability to state-of-the-art packaging techniques.

Therefore, it is an object of the present invention to provide an antistatic material useful in coating a semi-rigid substrate such as cardboard to produce a laminate for use in heat-sealable, skln packaging processes for the packaging of static sensitive devices, and/or conversion to boxes.

It i8 also an object that the protection from electrostatic charge afforded by the laminate is substantially independent of ambient humidity, i.e. the laminate is still able to decay an applied ~5000 VDC in less than about 3000 ms, more preferaoly less than about 2000 ms, when conditioned at less than about 15% relative humidity.
5/891227.3/SPECFLDRj01/10/90/02:59:47 PM

~J~ ~r~1 7 ~

It is another object that the laminate is permanently antistatic, i.e.
exhibit an SDT less than about 3000 ms, more prefer~bly less than 2000 ms, even after a 24 hour water shower, and/or aEter a 12 day o~en aging at about 70C.

Another object of the invention is to provide an antistatic packagc which is constructed Erom such a laminate.

A further object of the invention is the provision of a method for making such a laminate.

These and other objects of the invention will become readily apparent from the ensuing description when it is taken together with the following drawings.

SUMMARY OF THE INVENTIO~

The present invention provides an improvement over existing antistatic packaging materials by utilizing a permanently antistatic heat-&ealable coating layer applied to at least one surface of a semi-rigid substrate. The resulting packaging laminate can then be formed into an antistatic container for the packaging of static-sen&itive items, or a sheet of the laminate may provide antistatic protection and mechanical support to an item which is to be skin-packaged with a heat-sealable plastic sheet. Also such a coated cardboard is useful to make a skin package for devices in a medical operating room where explosive oxygen andlor ether are present and thus protection from static electricity must be provided. Also such coated cardboard may ~e advantageous~y employed for any skin packaging use requiring a plastic with a decreased tendency to accumulate dust.

The present invention provide& a semi-rigid, heat-sealable, laminate with permanent antistatic characteristics comprising a semi-rigid deformable substrate having a surface with a surface portion for supporting a static SenSitiVQ item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bonded to said surface, said layer including a modified acid copolymer selected from:

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

2 ~ 2 (I) a mixture of ~A) a polymer containing c~rboxylic acid moieties and (~) an antistatically eEfective amount of a quaternary amine;

or Erom (II) an acid/base reaction product of (A) a polymer containing carboxylic acid moieties and ~C) an antistatically effective amount of an organic or inorganic base amine wherein:

(A) the polymer containing carboxylic acid moieties i8 a copolymer of ~i) an alpha-olefin of the formula RCH=CH~ wherein R is H or Cl to C;ro alkyl, C~
to C~O alkoxy, or C~ aryl, and (ii) an alpha,beta-ethylenically unsaturated carboxylic acid, (B) the quaternary amine is of the formula [(R')~Rr)~R~ R~)N¦'[X¦- wherein R1 is selected from H, aryl, Cl to Cr,o alkyl optionally ha~ing one or more non-contiguou~ C=O or NHC=O or -S- or -0- in the carbon chain, or the same as R2 ;

each of R2, R:', and R~, is the same or different and selected from H, Cl to Cl~ alkyl optionally substituted with one or more OH or from -(Rri-O)~-H
where a is an integer from 1 to 10 and Rr3 ls ethylene or propylene; and X is an anion selected from chloride, bromide, iodide, fluoride, nitrate, fluoborate, phosphate, C, to C,O
alkyl phosphate, sulfate, C, to C~O alkyl sulfate, formate, Cl to C20 alkyl or C~ to C,r. alkaryl or aryl sulfonate, acetate, trifluoroacetate, citrate, 5/891227. 3JSPECFLDR/01/ 10/90/02: 59: 47 PM

2 i;~
propionate, or tartrate, and ~c~ the organic or inorganic base is of the formula IM]'IY~-, wherein IMl' is selected ~rom Li', Na', K', Rb', Cs', or R~R R~R ~N ', where R~, R', R~, and R~ are independently selected from a C~ to C~ alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, and Iy~~ is selected from hydroxlde, Cl to C. alkoxide, bicarbonate, or carbonate.

Optionally, an additional polymeric resin, which i8 described in further detail below, may be blended with the modified acid copolymor.

Referring to the anion X, preferably, the Cl to C~O alkyl phosphate is methyl phosphate or ethyl phosphate, the C, to C~O alkyl sulfate is methyl sulfate or ethyl sulfate, and the Cl to CZO alkyl or C~ to Ca~ alkaryl or aryl sulfonate is methanesulfonate, butanesulfonate, benzenesulfonate, or C, to C,~ alkyl benzenesulfonate.

The pre~ent invention also provides a method for making a semi-rlgid, heat-sealable, laminate with permanent antistatic characteristics compri~ing 1) modi~ying an acid copolymer by mixing with heat, optionally with solvent, ~A) a polymer containing carboxylic acid moieties and an antistatically effective amount of a modifier selected ~rom either ~B) a quaternary amine or ~C) an organic or inorganic base wherein:
.. ..
~A) the polymer containing carboxylic acid maieties is a copolymer of ~i) an alpha-olefin of the formula RCH=CH~ wherein R is H or C, to C~O alkyl, Cl to C~O alkoxy, or C~ aryl, and ~ii) an alpha,beta-ethylenically unsaturated carboxylic acid, 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

i2 and ~s) the quaternary amine is o~ the ~onmuls [(R')(R~)~R~)~R4)N¦' lX¦-wherein R` is selected from H, aryl, or Cl to C!jO alkyloptionally having one or more non-contiguous C=O or NHC=o or -S- or -0- in the carbon chain, or the same as R~;

each of R~, R3 and R4 is the same or different and selected from H, C1 to CIH alkyl optionally substituted with one or more OH or from -(R~-o~-H
where a is an integer from 1 to 10 and Rq is ethylene or propylene;

and X is an anion selected from chloride, bromlde, iodide, fluoride, nitrate, fluoborate, phosphate, Cl to C~
alkyl phosphate, sulfate, Cl to CH alkyl sulfate, formate, Ct to C~ alkyl or C~ to Cz4 alkaryl or aryl sulfonate, acetate, citrate, trifluoroacetate, propionate, or tartrate, (C) the organic or inorganic ba~e is of the formula [M)'IY~-, wherein [Ml~ is selected from Li~, Na~, R~, Rb-, Cs-, or R~R'RHR9N~, where R~, R7, RH, and R9 are independently selected from a C, to C~ alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, and lYl- is selected from hydroxide, C, to C4 alkoxide, bicarbonate, or carbonate, and 2) applying a layer of said modified acid copolymer to a sheet of semi-rigid substrate.
5/89l227.3/spEcFLDR/olJlo/9oJo2:s9:47 PM

Also, the present invention provides a package ~or enclosing static sensitive items, said package being constructed from a laminate comprising a semi-rigid substrate having an antistatic layer extending over and bonded to at least one surface o~ said substrate.

The present invention also provides a package for vacuum packaging a static sensitive item comprising:

~1) a semi-rigid substrate having a surface with a central supporting portion and a border portion surrounding said central supporting portion and a heat-sealable, antistatic layer extending over and bonded to substantially all of said surface, said layer including the above-described modified acid copolymer, and (2) a sheet of flexible, heat-sealable antistatic film covering said surface and bonded to said border portion to form a vacuum-sealed enclosure over said central supporting portion.

The present invention also provides a semi-rigid, heat-sealable laminate with permanently antistatic characteristics comprising a semi-rigid deformable substrate having a surface with a surface portion for supporting a static sensitive item to be packaged and a heat-sealable, antistatic layer extending over and bonded to said surface, said layer being resultant from mixing with heat, optionally with solvent, (A) a polymer containing carboxylic acid moieties and an antistatically effective amount of a modifier selected from either (8) a quaternary amine or (C) an organic or inorganic base wherein:

(A) the polymer containing carboxylic acid moieties is a copolymer of (i) an alpha-olefin of the formula RCH=CH2 wherein R is H or C~ to C2a alkyl, C~
to c2o alkoxy, or C~ aryl, and (ii) an alpha,beta-ethylenically un~aturated carboxylic acid, S/891227.3/SPECFLDR/01/10/90/02:59:47 PM

:~3 ~nd ~B) the quaternary amine ls of the ~ormula l~R ~(R )~R )~R~)N¦' IX¦-wherein ~' is selected erom H, aryl, or C~ to C!~o alkyloptionally having one or more non-contiguous C=O or NHC=O or -S- or -0- in the carbon chain, or the same as R~;

each of R~, R:~, and R~ is the same or different and selected from H, C~ to C,~ alkyl optionally substituted with one or more OH or from -~R~-O)~-H
where a is an integer from 1 to 10 and R~ is ethylene or propylene;

X is an anlon selected from chloride, bromlde, iodide, fluoride, nitrste, eluoborate, phosphate, C, to Cn alkyl phosphate, sulfate, C~ to C~ alkyl sulfate, formate, Cl to C~ alkyl or C~ to C~ alkaryl or aryl sulfonate, acetate, citrate, trifluoroacetate, propionate, or tartrate, . .
and (C~ the organic or inorganic base is of the formula IMl'IYl- , wherein [M]~ is selected from Li~, Na', K', Rb~, Cs', or R~R'RHRqN~, where R~, R7, RH, and R9 are independently salected from a C~ to C~ alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, and IY~- is selected from hydroxide, C , to C~ alkoxlde, bicarbonate, or carbonate.

/891227.3/SPECFLDR/01/10/90/02:59:47 PM
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The present invention also provides a semi-rigid, heat-sealable laminate with penmanently antistatic characteristics comprising a planar, scmi-rigid de~ormable s~bstrate having a surEace with a s~lrface portion for supporting an item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bonded to said surface, said layer obtained from mixing with heat, optionally with solvent, (Al ethylene-acrylic acid or ethylene-methacrylic acid and an antistatically effective amount of a modiEier selected rom either (B) or ~C) where (B) is a quaternary amine of the formula lR'~R~R~N¦~
lX¦~ where R' is a C4 to C,~, straight or branched alkyl optionally including one or more ether linkages, each of R~ and R:' and R~ is the same or different and selected from methyl or ethyl, and X is chloride, methyl sulfate, ethyl sulfate, methane sulfonate, toluene sulfonate, and (C) is an organic or inorganic base of the formula IM) IY) where [Ml~ is K~, Cs', or lR~7R~R9NI~
wherein R~, R', R~, and R9 are sèlected from methyl, ethyl, or C~H~OH and IY]~ is hydroxide, methoxlde, or ethoxide.

DETAILED DESCRIPTION OF THE DRAWINGS

AND OF THE INVENTION

Known in the packaging art are various ways to package static-sensitlve itemæ for storage or shipment. One packaging technique involves the assembly of a six-sided container, such as a box, in which the item to be packaged is enclosed. Another, more modern method, called "skin-packaging", consists of drawing a vacuum between the item and a semi-molten plastic sheet of film. The heated, semi molten sheet of fiLm bonds to itself and around the item during cooling, thereby forming a seal which maintains the vacuum between itself and the enclosed item.
Typically, when being skin-packaged, the item will be carried on a piece of sti$f material which provides a backing board as support for the item during the packaglng procedure. A packaging laminate which is useful with either packaging technique and which provides protection from static buildup for static-sensitive items such as electronic components is illustrated in FIG. 1.
5/891227.3/SPECFLDR/01/10~90/02:59:47 PM

As shown in FIG. 1, the Laminate o~ the invention, indicated generally by 10, comprises a substrate sheet of packaging material 1Z.
The substrate material preferably comprlses a standard packaging material which possesses sufficient stiffness or rigidity to provide support to an item to be packaged, yet which is deformable so that it can be shaped into the form of a package. Such a material can comprise, for example, cardboard or fiber board, either of which is commonly used to construct six-sided enclosure~ such as boxes for packaging electronic items.

A second layer 13 is formed on, and is co-extensive with a surface 14 of the substrate 12. Layer 13 possesses antistatic characteristics to prevent the buildup and discharge of static electricity between an item which is to be packaged and the surface of the packaging material 12 which encloses the item. Layer 13 is composed of a modified copolymer which provides the resulting laminate with the level of antistatic characteristic which is necessary to prevent the buildup of static charses. Layer 13 also possesses the characteristic of being able to bond to a semi-molten plastic film which is used in a skin-packaging process, i.e. it is heat-sealable.

One type of antistatic package which may be formed from a sheet o~ laminate having the structure illustrated in FIG. 1 and explained herein above can be understood with reference to FIGS. 2 and 3. FIG. 2 illustrates a sheet of antistatic laminate 15 which is fabricated according to the herein-described procedure and which has the shape of an X. The X includes a pair of opposing arms 16 and 18 and another pair of opposing arms 20 and 21. The anm 20 has a tab 22 along one edge and the arm 21 has a slot 23 which extends through the arm 21. An electronic circuit board 24 is placed on the area 25 which is formed by the intersection of the arms. The surface 26 of the sheet 15 upon which the circuit board 24 rests has been coated with an antistatic layer according to the procedure described herein.

The sheet 15 having the shape illustrated in FIG. 2 can be closed to hold the circuit board 24 in a six-sided container illustrated in FIG. 3. The coating of the surface 26 with the antistatic layer 5/8gl227.~/SPECFLDR/01/10/90/02:59:47 PM

prevents the buildup of a static charges which may accumulate while the sheet 15 and the circuit board 24 are being handled during pack~ging.

As illustrated in FIG. 3, the sheet 15 can be formed into a six-sided container by folding the opposing arms 16 and lB over the clrcuit board 24 and then folding first arm 21 and then arm 20 over the circuit board and over arms 16 and la. To keep the package closed, the tab 22 is inserted through the slot ~3.

FIG. 4 illustrates the use of a laminate fabricated according to the method of the invention in a skin-packaging procedure. In the procedure, a sheet of laminate 30 which is fabricated according to the herein-described method supports a printed circuit board 32 on a layer 33 of antistatic material. Preferably, the sheet 30 is cut so that a continuous border of the layer 33 surrounds the circuit board 32. The sheet 30 with the circuit board 32 resting thereon is then sealed by any typical skin-packaging technique with a fiLm of flexible plastic packaging material 34. During the packaging operation, the material 34 will bond to itself and to the layer 33 of antistatic material. This will enhance the quality of the completed package by increasing the total area of the completed bond. ~n apparatus which can form the skin-packaged container illustrated in FIG. 4 is available from Ampack Corporation under the model name "Poly-Tite, Port-A-Vac 300 Series".

During packaging, the package illustrated in FIG. 4 prevents the buildup of static charges between the laminate sheet 30 and the circuit board 32 by the provision of the antistatic layer 33. Use of an antistatic material for the flexible plastic sheet 34 will enhance the static prevention qualities of the FIG. 4 package. Sheet 34 may be formed from a flexible plastic film of acid copolymer and quaternary amine as described below. Also, circuit board 32 can b- aackaged between two sheets of material fabricated ~ording to the rein-described method with the coated surface 33 of ~ i~ gheet 30 cont. ~ng the circuit board 32~

The modified acid copolymer from which layer 13 may be formed is described in more detail below. One embodiment of this modified acid copolymer comprising a mixture with a quaternary amine is disclosed in 5/591227.3/SPECF~DR/01/10/90/02:59:47 PM

s~

commonly assigned copending US Serial NO 249,~88, Eiled September Z6, 1988, which is a Continuation-In-Part of copending US Serial NO. 143,885, Eiled January 14, 1988. The disclosures oE these two applications are incorporated herein by reference. Also for clarity, pertinent portions of these two applications are repeated below.

The acid copolymer is a polymer containing carboxylic acid moieties. By "polymers containiny carboxylic acid moieties" as that term is used herein it is intended to maan copolymers of (i) an alpha-olefin having the formula RCH=CH~ wherein R is H or C, to CJ~ alkyl, C1 to C~ alkoxy, or C~ aryl, and (ii) an alpha,beta-ethylenically unsaturated carboxylic acid. Pre~erably, when R is alkyl, it i8 C, to C~ alkyl. Also, preferably, the alpha,beta-ethylenically unsaturated carboxylic acid is present in an amount by mol % of about 50% or less, more preferably about 30~ or less, most preferably about 20~ or less.
Also, by the term "polymers containing carboxylic acid moieties", it i8 intendsd to mean that the copolymer of an alpha-olefin having the formula RHC=CH~ wherein R is H or C, to CZO alkyl, C~ to C~O alkoxy, or C~ aryl, and an alpha,beta-ethylenically unsaturated carboxylic acid may be partially neutralized with a suitable cation such as zinc cation or sodium cation. Thus, the polymer contalning carboxylic acid moieties may be an ionomer. Further, by the tsrm "polymers containing carboxylic acid moieties" it is intended to include carboxylic acid-forming moieties such as anhydrides.

The acid copolymer need not necessarily comprise a two component polymer. Thus, although the olefin content of the acid copolymer preferably is at least 50 mol percent, more than one olefin may be employed. Also, other copolymerizable monoethylenically unsaturated monomers may be employed in combination with the olefin and the carboxylic acid comonomer. It is intended also to include terpolymers. Accordingly, acid copolymers or terpolymers suitable for use in the present invention include, but are not limited to, ethylenetacrylic acid copolymers, ethylene/methacrylic acid copolymers, ethylene/itaconic acid copolymers, ethylene/methyl hydrogen maleate copolymers, ethylene/maleic acid copolymers, styrene/maleic acid copolymers, styrene/maleic half ester copolymers, alkyl vinyl ether/maleic acid copolymers, alkyl vinyl 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

e~her/maleic half ester copolymers, ethylene/methyl hydrogen maleate/ethyl acryLate terpolymers, ethylene/methacrylic acid/vinyl acetate terpolymers, ethylene/acrylic acid/vinyl acetate terpolymers, ethylene/acrylic acid/vinyl alcohol terpolymers, ethylene/propylene/acrylic acid terpolymers, ethylene/styrene/acrylic acid terpolymers, ethylene/ acrylic acid/lmethyl methacrylate terpolymers, ethylene/methacryliC acid/ ethyl ~crylate terpolymers, ethylene/itaconic acid/methyl methacrylate terpolymers, ethylene/methacrylic acid/acrylonitrile terpolymers, ethylene/ fumaric acid/vinyl methyl ether terpolymers, ethylene/vinyl chloride/acrylic acid terpolymers, ethylene/vinylidene chloride/acrylic acid terpolymers, ethylene/vinyl flouride/methacrylic acid terpolymers, and ethylene/ chlorotrifluroethylene/methacrylic acid terpolymers.

The copoly~er of an alpha-ole~in having the formula RCH=CH7 wherein R is H or C, to C~" alkyl, C, to C~O alkoxy, or C~
aryl, and an alpha,beta-ethylenically unsaturated carboxylic acid representatively may be produced by the Eree radical copolymerization of ethylene and a carboxylic acid comonomer therefor such as acrylic acid or methacrylic acid. Preferably, when R is alkyl, it is C, to CH.
Suitable such acid copolymers are the Primacor (TM) polymers, supplied by Dow Chemical Company, Midland, Michigan. Primacor is produced by the copolymerization of ethylene and acrylic acid. Ethylene-acrylic acid copolymers are herein referred to as EAA copolymer. A very suitable Primacor polymer is Primacor 1410 or Primacor 5981. Other suitable such acid copolymers are sold under the trade-name Nucrel by du Pont; they are produced by the copolymerization of ethylene and methacrylic acid.
Ethylene-methacrylic acid copolymers are herein reEerred to as EMAA
copolymers. Ionomers are commercially available as Surlyn (R) from the E.
I. du Pont de Nemours Company of WiLmington, Delaware, and are described ln detail in US Patents 3,355,319 and 3,845,163.

The amine is a quaternary amine of the formula l~R')(R~)(R3)(R~)N¦~[X¦- wherein R' is selected from H, aryl, or C, to C"O alkyl optionally having one or more non-contiguous C=O or NHC=O or -S- or -O- in the carbon chain, or the same as R~; each of R~, R3, and R4 is the same or different and selected from H, Cl to C H alkyl optionally substituted with one or more OH or from -(R~-O)"-H where a is an integer from 1 to 10 and R5 is ethylene or 5~891227.3/SPECFLDR/01/10/90/02:59:47 PM

propylene; and x is an anion selected Erom chloride, bromide, iodid~, ~luoride, nitrate, fll~oborate, phosphate, C, to C~ alkyl phosphate, sulfate, C~ to C~ alkyl sulEate, Eormate, C, to C~, alkyl or C~
to C!~ alkaryl or aryl sulfonate, acetate, citrate, propionate, or tartrate. Prefera`oly, the C, to C~,l alkyl phosphate is methyl phosphate or ethyl phosphate, the C, to C~O alkyl sulfate is methyl sulfat:e or ethyl sulfate, and the C, to C~O alkyl or C~ to C~4 alkaryl or aryl sulfonate is methanesulfonate, butanesulfonate, benzenesulfonate, or C, to C,t~ alkyl benzenesulfonate.

By "quaternary amine" as that term is employed herein, it is intended to include quaternary ammonium compounds and/or quaternary ammonium salts.

Suitable quaternary amines (QA) may be chosen from, but are not limited to, the methyl chloride salts of ethoxylated fatty amines.
Commercial ones are available from the Tomah Division (Milton, Wlsconsin) of Exxon Chemical and are represented by the formula:

(CH ~CH;~O)qH

Z-N-CH,' C1-(CH~CH~O),H

where Z is an alkyl or alkoxy radical, and q + t is the total number of moles of ethylene oxide in the chains. Examples of commercially available ones are as follows:

COMMERCIAL OUATERNARY AMINES
QA
Product Indent-ification Number Z q ~ t 5/891227.3JSPECFLDRJOl/10/90/02:59:47 PM
1PI . ..

~ ~ 3 3 i ~s ~
Q~ 2 C ~ OOC, 2 Q~ - 5 C, ~,OC, 5 Q-1"-15 C",OC, 15 Q-17-2 Cl ,OC, 2 Q-S-2 Soya 2 Q-S-5 Soya 5 Q-S-15 Soya 15 Q-1~-2 Cl~ 2 Q-18-5 C, H 5 Q--18--8 C ~ H 8 Q-18-10 Cl" 10 Q--18--15 C, H 15 Q-T-2 Tallow 2 Q-T-5 Tallow 5 Q-T-15 Tallow 15 Q-DT-3 "Tallow Diamine"

Other very suitable quaternary amines are the ethyl sulfate salts or methyl sulfate salts of alkoxylated fatty amines. Commercial ones are available under the trade-name Emerstat 6660 Erom Emery Indus-tries and it is believed from applicants' own chemical analysis that they are represented by the formula: ~A)~A')Nl~CH~CHJO)nH¦~ AIOSO3 where A i8 Cn to C.~O alkyl, A' is ethyl and n is an integer from 1 to 4. Also sultable are methyl sulfate salts such as that sold under the trade-name Cyastat by Cyanamid; it has the formula C "H~3CONHC3H~N~CH3~3~CH3OSO3-. Also suitable are ethosulfate salts such as that sold under the trade-name Larostat 264A
Anhydrous, which is a modified soyadimethyl ethylammonium ethosulfate.

Additional QA's may be prepared by reacting a tertiary amine (TA~ and an acid or alkylating agent, as further described in the Examples below.

A second embodiment of the modified acid copolymer comprises the acid/base reaction product of the acid copolymer and an antistatically effective amount of an organic or inorganic base. This is disclosed in copending USSN 164,756, filed March 7, 1988, to Roberts and Morgan, the disclosure of which i8 incorporated herein by reference. The organic or 5/891227.3/SPECP~DR/01/10/90~02:59:47 PM

7 -i ~

inorganic base is o~ the fon~ula IM~ IY]-, wh~rein [M~ is selected from Li , Na , K , Rb , Cs , or R~R'R R~N , where R~, R', R~, and R~ are independently selected ~rom a Cl to C~
alkylr benzyl, 2-hydroxyethyl, or hydroxypropyl, and lY]- is selected from hydroxide, C~ to C~ alkoxide, bicarbonate, or carbonate.

The polymer containing carboxylic acid moieties and the modifler selected from either the quaternary amine or from the organic or inorganic base are combined by mixing with heat, optionally with solvent.
Optionally, a polymer compatible therewith, such as a polyolefin, may be blended in the mixture. Any suitable mixing means may be employed such as a kettle, a blender or a twin screw extruder. The heat should be Erom aoout 50C to 290C, more pre~erably about 100C to 250C, even more preferably about 100C to 200C. Then the resultant may be formed into a fiLm by any of the various methods ~urther dlscussed below, and then laminated onto the cardboard to form a coating thereon. Lamination may be by heat and~or adhesive. Alternatively, the resultant may be extrusion coated onto the cardboard, or if solvent is present, sprayed or painted directly onto the cardboard to form a coating thereon.

The coating film is permanently antistatic. It will dissipate an applied charge of ~5000 Vdc in less than about 3000 ms, more preferably less than 2000 ms, using the method described in Federal Test Method Standard 101c, Method 4046.1, even after a 24 hour water shower, and/or after a 12 day oven aging at about 70C.

In general, it may be desirable to decrease the triboelectric charging propensity of the antistatic laminate. It has been discovered that this may be accomplished through the use of various low molecular weight additives, herein designated "triboelectric enhancers" or "enhancers". Examples XVI and XVII describe these enhancers further.
Particularly useful in this regard is an ethoxylated sorbitan ester, e.g.
polyoxyethylene (20) sorbitan monolaurate.

Based on the % weight amount of polymer containing carboxylic acid moieties, it is preferred that the modifier selected from either the quaternary amine or from the organic base or inorganic base be present in a weight % amount up to about 50%, more preferably up to about 30~, even 5~891227.3/SPECFLDR/01/10/90/02:59:47 PM

~ ~ <,'J 'L t_3 3 more preferab~y up to about 20~. Based on the total composition weight, which optionally may contain polyolefin, preferabLy the quaternary amine is present in a weight ~ amount of about 0.001~ to about 30%, more preferably about 0.01% to about 20~, and even more preferably about 2% to about lO~. In the case of the organic or inorganic base, the mol % of base relative to carboxylic acid moieties in the polymer is 20% to 100%, preferably 50~ to lO0~. In no case should the mol % of organic or lno~ganic base exceed 100%. If a triboelectric enhancer is used, the preferred use level, based on the total composition weight, is about 0.001% to about 30%, more preferably about 0.01~ to about 20%, and even more preferably about 2% to about 10%.

Many polymer resins are suitable polymers for blending with the modified acid copolymer. Unless specifically set forth and defined or otherwise limited, the tenms "polymer" or "polymer resin" as used herein generally include, but are not limited to, homopolymers, copolymers, such as, for example block, graft, random and alternating copolymers, terpolymers etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited the terms "polymer" or "polymer resin" shall include all possible structures of the material. These structures include, but are not limlted to, isotactic, syndiotactic and random symmetries. Particularly suitable for blending are the polyoleflns. The term "polyoleEin" as used herein generally includes, but is not limited to, materials such as polyethylene ~PE), polypropylene ~PP), ethylene-vinyl acetate (EVA), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene ~LDPE), very low density linear polyethylene (VLDPE), ethylene/alkyl-acrylate copolymer (EAlAcr) and the like, the homopolymers, copolymers, terpolymers etc. thereof, and blends and modifications thereof. The term "polyolefin" shall include all possible structures thereof, which includes, but is not limited to, isotactic, syndiotactic and random symmetries.

Blends of all families of polyolefins, such as blends of EVA, EAlAcr, PP, LDPE, HDPE, VLDPE, and LLDPE, may also be advantageously em-ployed.

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

Me~suring the antistatic property: The antistatic property is exhibited by the ability of the polymer containing the agent to promote static charge decay, i.e. ~o dissipate a static charge. The polymer alone will not dissipate a static charge, but the polymer containing the agent is ~le to dissipate 99% of an applied static charge of ~5000 volts di-rect current (Vdc) in a short amount of time, l.e. less than 3 seconds, ~3000 milliseconds) more preferably less than 2 seconds (2000 milliseconds). Federal Test Method Standard 101c, Method 4046.1, "Electrostatic Properties of Materials" states less than 2000 ms and thus it is preferred to have a material that complies with l01c. Decay meters for measuring the time for dissipation of the applied volts are commercially available, such as the 406C static decay meter supplied by Electrotech Systems, Inc. Unless otherwise indicated in the Examples below, the films, prior to testing, were equilibrated at less than about 15~ relative humidity (RH) at about room temperature (RT) for about 24 hours.

Some antistatic materials wer~ tested for triboelectric charge generation. The procedure is described in an article entitled "Triboelectricity and Surface Resistivity do not Correlate", EOS/ESD
Symposium, Anaheim, California, September, 1988, by S.L. Fowler. To summarize, two aluminum plates were used for this test. Plate 1 was a ground plane and was about 12 inches (30.5 cm) x 12 inches (30.5 cm) x 3/16 inch (0.5 cm) in size. Plate 2 was about 4 inches (10.2 cm) X 3 inches (7.6 cm) X 3/16 inch (0.5 cm) in size and had a non-contacting static voltmeter attached to it. Plate 2 also had an insulating rod or handle attached to it to allow the person performing the test to separate the plates without touching them and affecting the charge accumulation.
The test wa~ performed at 50~ RH. The sample under test was placed on Plate 1. Plate 2 was pushed against the sample to make intimate contact with it. Plate 2 was then separated rapidly up against a stop, while the sample remained in contact with Plate 1. This stop limited the travel to approximately 1 inch (2.54 cm) of separation between the two plates. This procedure was repeated 4 times and the voltmeter readings averaged.
Sometimes various materials were attached to the pair of aluminum plates, a~ designated in the Examples below. For instance, employed were aluminum 5/891227.3/SP~CFLDR/01/10/90/02:59:47 PM
2~

plates having attached thereto EVA, solder-masked circuit board, ceramic inte~rated circuit, and copper. The idea was to test for trib~electric propensity against material that will appear in real life packaging situations. The principle of this measurement is that when two materials are placed in contact and then separated they give up or take on electrons thus leaving both màterials with a net cllargQ. Since one of the materials ln the test is a metal plate, the charge on it can be measured by a static voltmeter. The magnitude and polarity of the charge is then an indicator of the tribo-charging propensity of the material under test. The voltage decreases with the use of enhancers as described in Examples XVI and XVII
below, which is desirable.

Some of the antistatic materials were tested for surface resistivity and volume resistivity according to ASTM D257. There is not necessarily a correlation between the surface or volume resistivity of a film and the ability of a film to decay or dissipate charges. Thus, the term "antistatic" as used herein describes a material which can dissipate 99% of an applied static charge of +5000 Vdc in a short amount of time, preferably a static decay time less than about 3 seconds, more preferably less than about 2 seconds (Federal Test Method Standard lOlc, Method 4046.1, "E1ectrostatic Propertles of Materials"). If the material also happens to have an antistatic resistivity, i.e. a surface resistivity of about 10~ to 10'1 ohms/square as further described below, then that material will be described using the term "antistatic surface resistivity."

The Department of De~ense and the Electronics Industry Associa-tion have standards on surface resistivity of a material in ohmstsquare as follows:

Surface Resistivity Ranqes (ohms/square) Antistatic or InsulativeStatic Dissipatlve Conductive greater than 10l2 1012 to 105 less than 105 5/B91227.~/SPECFLDR/01~10/90/02:59:~7 PM
2~

, " ~

There is no correlation between triboelectric propensity and either surface resistivity or static decay time.

It is noted that some of the 5-layer films of the invention, as illustrated by Examples XIII and XIV below, have both a preferred static decay time oE about 3000 milliseconds or less and a static di9sipative (as opposed to insulative) surface resistivity oE 101~ to loJ ohms/square, even after a 24-hour water shower or after 12 days in a hot oven. Thus these S-layer fiLms are permanently antistatic by the definition of static decay time under about 3000 ms. Also they exhibit a permanently antistatic surface resistivity. Neither the Z4-hour water shower nor the 12-day hot oven takes out the "antistatic" SDT characteristic or the "antistatic" surface resistivity characteristic.

Some of the antistatic materials were tested for crazing, i.e.
polycarbonate compatibility, which was a test developed by General Electric Company, published as their "LEXAN ~R) Resin Technifacts" T-47 test method. This test consists of bending or flexing test coupons or bars of LEXAN (R) about 1/8 inch (0.32 cm) thick on metal jigs to several known stress levels of about 500 to 3400 psi (35 to 239 kg/cm~) and the material being evaluated is then applied to the stressed coupons and the combination maintained at several temperatures for S days. The temperatures are about 73F ~Z2.8C), lZ0F (48.9C), 158F (70C), and 185F (85C). A comparison of the strain independent of the material being evaluated, the radius of the curvature of the upper surface of the jig, and the stress level of the LEXAN ~R) bars is as follows:

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

STRESS LEVEI. RADIUS OF UPPER S~RAIN INDEPEN-lJ8" THIC~ BM S SURFACE OF JIG VENT OF MATERIAL
llNFILLED LEXAN_RESIN
PSI kg/cm' Inches cm Percent 500 35 42.437 107.8 0.15 750 53 28.270 71.8 0.22 1000 70 21.187 53.~ 0.29 1250 88 17.063 43.3 0.37 1500 l05 14.103 35.8 0.44 1750 123 12.080 3U.7 ,0.51 2000 141 10.563 26.8 0.59 2250 158 9.381 23.8 0.66 2S00 176 8.437 21.4 0.74 2750 193 7.664 19.5 0.81 3000 211 7.020 17.8 0.88 3400 239 6.187 15.7 At the end of the exposure, the bars are visually checked for crazing.Results are reported as the maximum stress to which the bar can be subject-ed while in contact with the particular environment without the occurrence of crazing. It is desired that the film exhibit no crazing or only very slight crazing at a temperature 158F (70C) and stress of 1700 psi, more preferably a temperature of 185F (85C) and stress of 1700 psi.

The manufacture of film is known to those in the art. For exam-ple, see US Patent Nos. 4,274,900; 4,229,241; 4,194,039; 4,188,443;
4,048,428; 3,555,604; 3,741,253; 3,821,182 and 3,022,543. The disclosures of these patents are generally representative of such processes and are hereby incorporated by reference.

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

Other process variations ~or forming ~ilms are known to those in the art. For example, conventlonal pressing, thermoforming or l~ninat-ing tlechniques (including corona laminating) may be employed. For in-stance, multiple layers may be first coextruded with more layers then being laminated thereon, or two multi-layer tubes may be coextruded with one of the tubes thereafter being laminated onto the other.

Advantageously, an outside polymeric layer of a film may in-clude a small amount o~ about 10% by weight or less, more desirably about 7~ by weight or less of an antiblock, to adjust the degree of tackincss.
A suitable antiblock i8 EPE 8160 supplied by Teknor Apex.

The following Examples are intended to illustrate the preferred embodiments of the invention and comparisons thereto. It is not intended to limit the invention thereby.

Unless indicated otherwise in the Examples, the testing for static decay time (SDT) was done after Equilibration for 24 hours, at about room temperature (RT), at less than about 15~ relative humidity (RH). Also it is noted that sometimes SDT testing was done to samples that had been subjected to abuse such as 1 to 12 day~ in a hot, about 160F ~71C), oven or a 24-hour water shower. Where the oven is designat-ed as "humid", a beaker of water had been kept in the oven with the ~ilm sample during testing to maintain a "humid" atmosphere; otherwise the oven was simply a "dry" or "ambient" oven, without any water beaker.

MATERIALS EMPLOYED IN TllE EXAMPLES

ANTIBLOC~ INGREDIENTS SUPPLIER
Polyethylene Containing EPE 8160 Micron Sized Silica Teknor Apex XU61512.08L 0.80 0.910 Octene Dow Chemlcal LLDPE MI DENSITY COMONOMER SUPPLIER
DOWLEX 1.1 0.920 Octene Dow Chemical 2045.03 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

f 1 Dowlex 4002 3.3 0.912 Octene Dow Chemical EVA MI~ VA COMONOMER SUPPLIER
LD318.92 2.0 9 Vinyl AcetateExxon Alathon Vinyl Acetatedu Pont 3165 0.718 ~ BY WEIGHT ~ BY WEIGHT
EM MI ACRYLIC ACID ETHYLENESUPPLIER
.
PRIMACOR 1.S 9 91Dow Chemical PRIMACOR 300 20 80Dow Chemical PRIMACOR 300 20 80Dow Chemical 598~
ZINC METHACRYLATE
IONOMER OF EMAA FORMUL~A _ SUPPLIER
Surlyn 1650 Partially zinc neutralizeddu Pont ethylene methacrylic acid copolymer % BY WEIGHT ~ BY WEIGHT SUPPLIER
EMAA MI METHACRYLIC ACID ETHYLENE
Nucrel 1207 7 12 88 du Pont Nucrel 1202 2 12 88 du Pont ~A FORMULA SUPPLIER
-Q-14-2 ~C1oH2~OC3H~N(CzH~OH)zCH3l'C1-To~ah Div. of Exxon Emerstat IH(CH2)~_zo¦~CzH9)NI(C2H~O~ H¦ ~ C~HSOSO3-6660 Emery Industries Cyastat C1lHz3CONHC~H~N(CH~)3-CH30SO~-Cyanamid Larostat Modified soyadimethyl Jordan/PPG/Mazer 264A ~ ethylammonium ethosulfate Anhydrous TMAH Tetramethylammonium hydroxideSouthwestern Analytical Chemicals Div. of Mooney 5/891227.3~SPECFLDR~01/10/90/02:59:47 PM

r~

TA FORMULA SUPPLIER

Empigen AB Lauryl dimethylamlne Albright Wilson Empigen AY H(CH~ OC~H 4) ~ N( CH3)~
Albright &
Wi~son E-14-2 C,~,H~,OC,H~N~C~H~OH)~
Tomah Div., Exxon DMCA N,N-dimethylcocoamine Akzo Chemie ACID OR
ALKYLATING
AGENT FORMULA SUPPLIER

MSA Methanesulfonic Acid Aldrich DSSA H~CH;.)1 ~-,HC"H.,SO,H
Alfa/Morton Thiokol DES Diethyl Sulate Aldrich ~MI is melt index.

Acid SMA Formula M.W. Number SuPPlier 1000 1:1 styrene~maleic anhydride 1600 480 Sartomer 1440 Half-ester of maleic anhydride 2500 175 Sartomer 17352 Half-ester of maleic anhydride 1700 270 Sartomer 2000 2:1 styrene/maleic anhydride 1700 350 Sartomer 2625 Half-ester of maleic anhydride 1900 220 5artomer Triboelectric Enhancers: SuPPliers Amphoteric L: coco amphoteric Tomah-Exxon S/891227.3/SPECFLDR/01/10/90/02:59:47 PM

AO-1~-2: Bishy-3roxyethylisodecyloxypropyl amine o~ide Tomah-Exxon AO-728: alkyloxypropyl ~mirle oxide Tom~h-Exxon Miranol CM-SF: coco amphopropionat~ Miranol, Inc.
Miranol OS-D: oleoamphopropyl sulfonate Miranol, Inc.
Pluronic D62: ethyLene oxide propylene oxide copolymer BASF
Stepanol DEA: Diethanolamine lauryl sulfate ,Stepan Zonyl FSN: flurosurfactant du Pont Steol CA-460: ammonium laureth sulfate Stepan Stepanol WAT: tetraethylammonium lauryl sulfate Stepan Hexcel 106G: [Bis~2-hydroxyethyl)octyl ~thyl ammonium p-toluene sulfate Calfax 10L45: sodium mono- and di-decyl disulfonated Pilot diphenyl oxide Chemical Company Tween 20: Polyoxyethylene (20) sorbitan monolaurate ICI Americas Glycerol: HOCH~CH(OH)CH~OH Aldrich Ethylene glycol: HOCH~CH~OH Aldrich Propylene glycol: 1,2-propanediol Baker Tetraethylene glycol: O~CH~CH~OCH~CH~OH)z Aldrich Bacote 20: Zirconium ammonium carbonate Magnesium Electron, Inc.
Dow "Stature": XUS 15210.00L experimental additive Dow eXAMPLe I

LLDPE and EAA (Primacor 5981) weré premixed in parts by weight and then blended therein with heating was a QA in parts by weight. The rssultant mix of LLDPE + EAA + QA was then further blended in an amount of 33-1/3% by wt. with EAA (Primacor 1410) in an amount of 66-2/3% by wt. and that was hot blown into an extruded, tubular film. Films were about 1.5 to 2 mils (0.04 to 0.05 mm) thick. What was made is listed in Table IA.

T~3LE IA
60 parts by wt LLDPE IDowlex2045.03¦) 15 parts by wt QA IQ-14-2¦ ) 33-1/3% by wt mix of LLDPE+EAA+QA
30 parts by wt EAA lPrimacor 5981¦ ) 66-2/3% by wt EAA IPrimacorl410¦
100~ Resultant Film 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

,. i~ , l ~ ~ :~t k,~
Then, the following electrical measurements were tak~n on samples of film AS reported in Tabla IB.

TABLE IB
SAMPLE
A Static Decay Time as is 180 ms B Static Decay Time after 24 hours 992 ms water shower C Static Decay Time after days 3 days 783 ms in hot oven at 71C 5 days 1149 ms 9 days 7340 ms 12 days 14683 ms D Surface resistivity as is 2xlOI~ ohms~square E Volume resistivity as is 8.7 x 10'~ ohm-cm after 24 hr. water shower 1.5 x IOt~ ohm-cm after 12 day dry oven 1.8 x 1014 ohm-cm The results show the film performed well as an antistatic film both in terms of static decay time and resistivity, and was resistant to abusive aging, except that it did not survive 12 days in a hot oven, with a desir-able SDT of about 3000 ms or less.

EXAMPLE I(i?

Coated samples of cardboard are prepared by laminating the film of Example I thereto. These samples should exhibit excellent adhesion to a fiLm of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE II

Films were made as in Example I except that this time ths QA
was Emerstat 6660 supplied by Emery Industries. The resultant fiLm that was made is as listed in Table IIA below.

5/891227.3/SPECFLD~/01/10/90/02:S9:47 PM

~`D ;~ J~

TABLE IIA

60 parts by wt LLDPE IDOW1eX 2045.031) lS parts by wt QA [Emerstat 6660¦ ) 33-l/3~ by wt Mix of LLDPE+EM~QA
30 parts by wt EAA 1Primacor 59811 66-2/3~ by wt EAA ~Primacor 1410¦
lO0~ Resultant Film Then, the following electrical measurements were taken on samples of film as reported in Table IIB.
TABLE IIB
SAMPLE
A Static Decay Time as is 209 ms B Static Decay Time after 24 hours 539 ms water shower C Static Decay Time after days 3 days 78 ms in hot oven at 71C 5 days 97 ms 9 days 36l ms 12 days 195 ms D Surface resistivity as is 1.2 x lO " ohms/square E Volume resistivity as i5 2.8 x lOl' ohm-cm after 24 hr. water shower 2.2 x 10~7 ohm-cm after 12 day hot dry oven l.3 x lO'~ ohm-cm The results show the film performed well as an antistatic film both in terms of decay time and resistivity, and was resi~tant to abusive aging.

EXAMPLE II(i~

Coated samples of cardboard are prepared by laminating-the film of Example II thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE III

By blending with heat using a Berstorff twin screw extruder, a premix of pellets was made. First, 60 parts by weight EVA [LD3l8.92¦ and 30 parts by weight EAA lPrimacor 5981¦ were mixed, and then added thereto 5/89l227.3/SPECFLD~/Ol/lO/90/02:59:47 PM

~~J ;~
was l5 parts by wt QA (Emerstat 66601. The resultant EVA ~ EAA ~ QA was then ~urther blended with more polymer, and hot blown, 5-layer, extruded, tubular film having a thickness of about 4 mil ~0.102 mm) was m~de. The ingr~dients of each layer were as recited in Table IIIA and are in ~ by we~ght.

TABLE IIIA
OUTSIDE INTERIOR CORE INTERIOR OUTSIDE

95~ EVA 66-Z/3% EVA 90~ LLDPE 66-2/3% EVA 9S~ EYA
5~ Anti- 33-1/3% Mix 10~ Mix of 33-1/3% Mix 5% Anti-blockof EVA~EAA~QA EVA+EAA+QA of EVA+EAA~QA block Then, the following electrical measurements were taken on samples of film as reported in Table IIIB. Testing for triboel~ctric charging was against aluminum plates.

TABLE IIIB

Abuse Treat-ment Static DecaY Time(ms) Noted I Hr. 24 Hr.
or Equilibratlon Equllibration Film Ohms/square Ohms-cm for the FlLm ~or the Fllm Tested Surface Volume as is or after as is or after Tribo As is Res!,tivitY Resistivity abuse treatment abuse treatment Volts As is 1.8x10'3 7.0x10'3 111 222 -1.2 1 Hr. 1.4x10~4 2.1x10~4 7 177 181.9 Shower 3 Hr. 5.7x10'4 1.6x10'4 Less Than 115 161.5 Shower MMSDT*
24 Hr. 6.4xl0'~ 4.4x10'4 Less Than 102 76.4 Shower MMSDT
24 Hr. 1.6x10'3 2.5x10'4 183 328 48.6 Hot Humid O~en 5/891227.3/SPECFLDR/01/10/90/02:S9:47 PM

~ Sj . , S ':'~; J

~lot D~y Oven Day 1 NT*~ NT 332 185 NT
Day ;2 NT NT 272 178 NT
Day 3 NT NT 180 164 NT
Day 4 NT NT ~87 Won't NT
Accept Full Charge Day 5 NT NT 148 115 NT
Day 6 NT NT 164 348 NT
Day 7 NT NT 359 200 NT
Day 8 NT NT NT 455 NT
Day 9 NT NT 400 97 NT
Day 10 NT NT 213 2S9 NT
Day 11 NT NT 247 93 NT
Day 12 4.Zx10l'1.0x101~ 299 164 19.3 ~MMSDT = minimum measurable static decay time ~*NT - not tested It is noted from Table IIIB that while the resistivity measure-ments bordered between antistatic and insulative ~i.e. 10~3 to 10'~), the static decay ti~es were excellent, well under the preferred 2000 ms or less, even after the hot oven abuse or the water shower abuse. As for the film sample that would not accept a full charge after day 4 of the hot dry oven, while it is not intended to be bound to any theory, it is believed this happened due to a mechanical difficulty in that the sample was placed in the test meter in a curved or bowed position instead of a flat, taut position, with respect to the sensing electrode. (It is also noted that 2 similar 5-layer films were made, the only difference being that core layer 3 contained only 5% of the premix of EVA ~ EAA ~ QA or contained no premix 5/891227.3/SPECFLDR/01/10~90/02:59:47 PM

~ 3 ~
o~ EVA ~ EAA ~ QA. These siniLar films performed substantially the same, but for not accepting a full charge during the SDT test after 10 to 12 days in a hot dry oven. While it is not intended to be bound to any theo-ry, it is believed this was also due to a mechanical difficulty in that samples WerQ placed in the test meter in a bowed position.) EXAMPLE_III(i) Coated samples of cardboard are prepared by la~inating the EiLm of Example III thereto. These samples should exhibit excellent adhesion to a film of zinc ~ethacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE IV

Six tubes of a 5-layer film were made as in Example III, but containing the following amounts of ingredients for each layer as recited in Table IVA below:

TABLE IVA

LaYer 1 Laver 2 LaYer 3 LaYer 4 LaYer S
90~ EVA 66-2/3% EVA 90% LLDPE 66-2/3% EVA 90% EVA
10~ Anti- 33-1/3~ Mix 10% Mix of 33-1/3% Mix 10% Anti-blockof EVA+EAA+QA EVAIEAA~QA of EVA~EAA~QA block Samples of the 6 tubes of the 5-layer film were tested for static decay time after 1 hour of equilibration and the results were as reported in Table IVB below:

TABLE IVB

SAMPLE OF FILM SDT ~ms) Tube 1 14 Tube 2 43 5/891227.3/SP~CFLDR/01/10/90/02:S9:47 PM

. .

f ~ L' '' J

Tube 3 9 Tube 4 23 Tube 5 3l Tube 6 18 As can be seen, excellent SDT~s were obtained.

Next 3 sets of 4 samples each of the 6 tubes of 5-layer Film were subjected to a 24-hour water shower. Then, each set was equilibrated for 1 hour, 24 hours, and 48 hours, respectively and then checked for SDT. The results were as reported in Table IVC below:
TABLE IVC
SDT_ (ms) After 1 Hour After 24 Hours After 48 Hours TubeSample Equilibration ~gY~ Le~9n Equilibration 1 1 Less Than 24 29 MMSDT*
1 2 Less Than 23 41 MMSDT
1 3 Less Than 15 23 MMSDT
1 4 Less Than 16 24 MMSDT
2 1 Le6s Than 60 54 MMSDT
2 2 Less Than 54 50 MMSDT ...
2 3 Less Than 71 66 MMSDT
2 4 Less Than 70 71 MMSDT
3 1 Less Than l8 16 MMSDT
3 2 Less Than 17 20 MMSDT
3 3 Less Than 13 20 MMSDT
3 4 Less Than 11 18 MMSDT
4 1 Less Than 76 78 MMSDT
4 2 Less Than 38 32 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

7 1 ,~
HMSDT
3 Less Than 53 60 MMSDT
4 Less Than 84 85 MMSDT
1 Less Than 69 65 MMSDT
S 2 Less Than B4 76 MMSDT
3 Less Than 32 30 MMSDT
4 Less Than 33 34 MMSDT

6 1 Less Than 106 108 MMSDT
6 2 Less Than 114 136 MMSDT
6 3 Less Than 64 92 MMSDT
6 4 Less Than 152 161 MMSDT
*MMSDT = Minimum measurable static decay time As can be seen, when film was left to equilibrate for 24 hours, which is as per the specifications of Federal Test Method 101c, then excel-lent SDT's were obtained. Also, the flLm retained excellent SDT' 5 even after further Equilibration. Thus, these films indeed survived the vigor-ous abuse of a 24 hour water shower.

EXAMPLE IVli) Co~ted samples of cardboard are prepared by laminating the fiLm oE Example IV thereto. These samples should exhibit excellent adheaion to a film of zinc methacrylate lonomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE V

For polycarbonate compatibility, i.e. crazing tests, also a mono-layer film was extruded from the pellets of premix having the ingredi-ents as recited in Table V-A below:

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

3 ~, "

TABLE V-A

60 parts by wt ~LDPE IDowlex 2045.03¦
l5 parts by wt QA IQ-14-2¦
30 parts by wt EAA IPrimacor 5981¦

and then both a sample from Tube 1 of the 5-layer film of Example IV and a sample from the mono-layer film were tested for crazing of polycarbonate.
The results are summarized ln Table V-B below:

T~3LE V-B

Tube 1 of Test Conditions5-layer Mono-layer TemperaturePressure Film Film 73F122.8C) PSI ka/cm~

120F~48.9C) 15BF(70C) 185F~85C) 5~891227.3tSPECFLDR/01/10/90/02:59:47 PM

~` .1 ,J ,1, ~ J ~ /,, " ~

3400 ~9 VSLC .SLC
N ~ NO ATTACK
VSLC = VERY SLIGHT CRAZE
SLC = SLIGHTLY CRAZED
As can be seen the 5-layer fiLm D performed excellently and did not exhibit very sllght crazing till the most extreme condition of 3400 psi, whereas the mono-layer film only showed very sliyht crazing beginning at a less extreme condition of 2000 psi.

EXAMPLE V(i) Coated samples of cardboard are prepared by laminating the film of Example V thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate ionomer of EMAA when tested on an Ampack skin pac~aging machine.

EXAMPLE_VI

Quaternary amine additives QAl-QA5 (below) were prepared by mixlng the following TA'~ (tertiary amines) and acids or alkylating agents without solvent for the indicated time/temp.

TABLE VIA

Acid or Alkylating Time/
~A Formula TA(qms) Aqent(qms) Temp.
OAl H(CHz)~N(CH3)2H~ Empigen MSA lO min./

CH3SO3- (8.8) (3.2) 60C

5/891227.3/SPECFLDR/Ol/lO/90/02:59:47 PM

~(CH 2 ) ~ aN(CH.~)~C~H-~ Empigen DES 16 hr~
AB
C~H.~0503- ~8.8) (S.2) 60"C
QA3 H(C~ OC7~) ,, ., Empigen MSA lO min/
AY
N(CH~)~H CH~SO~ (14.4) (3.2) 60-'C

C~oH~IOCJH~N(C~H~OH)2H' E14-2 MSA lO min/
CHlS0,- (12.4) (3.2) 60"C

C~oH~IOC~H~N(C~H~OH)~H~ E14-2 DBSA 10 min~
H(Cil~) I7_I AC~H4SO~- ( 12.4) (10.0) 60~C

Several quaternary amines (QA, 3.6 parts by weight) were blended with Primacor 5981 ethylene-acrylic acid copolymer (7.1 parts by weight) and LD318.92 ethylene-vinyl acetate copolymer ~89.3 parts by weight). The blending was carried out by kneading a~ 130-150C for approximately 20 minutes in a Brabender Plasticorder (R) mixer. Samples of the resultant materials were pressed at approximately 1,000 psi (70 kg/cm) between plat-ens heated to 150C. Monolayer films of about 3 inches (7.6 cm) by 5 inches (12.7 cm) by 0.005 inch (0.013 cm) were thus obtained. The SDT of each film was determined before and after a 24-hour water shower. The results are summarlzed below:

SDT Before SDT After Sample QAShower (ms) Shower (ms) 3 QAl 90 510 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

These results demonstrate that the performance of the Eilms tested was sllghtly degraded by an extensive water shower, but still less than 3000 ms for Sample 1 and less than the preferred 2000 ms for Samples 2, 3, and 4.

Next, several quaternary amines ~QA 5.0 parts by weight) were blended with Primacor 1410 ethylene-acrylic acid copolymer ~71.3 parts by weight) and LD318.92 ethylene-vinyl acetate copolymer (23.7 parts by weight). The blending and subsequent film preparation and testing were carried out as described above for the samples reported in Table VIB. The results were as fo}lows:

TABLE VIC

SDT 8efore SDT After Sample Q Shower (ms) Shower (ms) Cyastat LS420 500 6 Larostat 264A 590 630 These results demonstrate that there was aLmost no loss of static decay performance after extensive water washing, and all SDT's were less than the preferred 2000 ms.

To demonstrate further permanence of these materials, the same samples S through 9 Erom after the water shower were further aged for 12 days in an oven at 70C and ambient humldity, i.e. a "dry" oven as there was no water beaker. SDT, surface resistivity, and volume resistivity for the resulting films are given below:

5/891227.3/SPECFLD~/01/10/90/02:59:47 PM
~0 ~iJ .I~
TABLE VID

Surface Re~istivity Volume Resistivity SamPleSDT ~ms? (ohms/square) ~ohm-cmL _ 1660 1.1x10':' 4.4x10'~
6 17gO 4.0x10'~ 1.3x10'~
7 330 3.8x10'` 7.7x10' 8 790 4.7x10'' 9 1x10' 9 120 3.8xlOl' 1.1x101l The results demonstrate that films produced with 5~ of a QA
additive in an EAA/EVA resin show excellent static decay times, surface resistlvities, and volume resistivities, and are highly permanent, i.e., insensitive to water washout of additive and 12-day aging at elevated temperature.

EXAMPLE VI (1) Coated samples of cardboard are prepared by laminating the EiLms of Example VI thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate ionomer of EHAA when tested on an Ampack skin packaging machine.

Comparative Example VII

A comparative sample was run for comparison with Sample 5 as reported in Tables VIC and VID above to show the result of omitting the ethylene-acrylic acid copolymer from the formulation. Thus, Cyastat LS
(5.0 parts by weight) and LD318.92 ethylene-vinyl acetate copolymer (95.0 parts by weight) were kneaded at 130-l50~C in a Brabender Plasticorder ~R) mixer. Effective mixing of these ingredients was never obtained, even after 4 hours of kneading. Reduction of the additive content to 2.5 parts S/891227 3/SPECFLDR/01/10/90/02:S9:47 PM
4t ~ ;S6 ~L ,.:, by weight did not solve the problem. Thls demonstrates that an acid copolym~r containing carboxylic acid moietie~ (i.e. the ethylenQ-acrylic acid copolymer) plays a critical role in compatibilizing the polyolefin with the ionic additive.

~ nother comparative s.1mple was run but this time for comparison with ';ample 9 as reported in Tables VIC and VID above to show the result of omitting the ethylene-acrylic acid copolymer ~rom the formulation.
Thus, QA2 (1.5 parts by weight) and LD318.92 ethylene-vinyl acetate copolymer (98.5 parts by weight) were kneaded at 130-150C in a Brabender Plasticorder (R) mixer. Effective mixing of these ingredie~ts was ob-tained, finally after 4 hours of kneading. Some of the resultant material was pressed at approximately 1000 psl (70 kg/cm~) between platens heated to 150C. Mono-layer fiLm of about 3 X 5 X 0.005 inches t7.6 X 12.7 X
0.013 cm) was thus obtained. The SDT of each ~ilm was determined before and after a 24-hour water shower. The results are summarized below:

TABLE VII

SDT Before SDT After Shower (ms) Shower (ms) 580 over 30000 Also, after the water shower, the film held a charge of 10 kilovolts, which indicates the antistatic property was lost. This demonstrates that an acid copolymer containing carboxylic acid moieties (i.e. the ethylene-acrylic acid copolymer) plays a critical role in providing permanent anti-static characteristics, i.e. enabling the film still to have a SDT less than about 3000 ms, more preferably less than about 2000 ms, after a 24-hour water shower.

EXAMPLE VIII

Quaternary amine QA2 (as defined in Table VIA, 6.0 parts) was blended with Surlyn 1650 partially zinc neutralized ethy1ene-methacrylic acid-zinc methacrylate ionomer (23.5 parts) and LD318.92 ethylene-vinyl 5/891227.3/SPECFLDR~01/10/90/02:59:47 PM

~ . i J

acetate copolymer ~70.5 parts). The blending and su~sequent testing were carried out as described in Example VI. The results were as Eollows:

Before Water Shower:
SDT ~ms) ~70 Surface Resistivity ~ohms/square) 1.7 x 10'~
Volume Resistivity (ohm-cm) 2.5 x lO'~
After 24-Hour Water_Shower:
SDT (ms) 880 Surface Resistivity (ohms/square) 7.6 x lot 2 Volume Resistivity (ohm-cm) 3.6 x 10`
After 24-Hour Water Shower Followed bv 12-DaY/70C Aqina:
SDT (ms) 460 Surface Resistivity (ohms/square) 1.7 x 10 Volume Resistivity ~ohm-cm) 2.5 x 10'~
These results demonstrate that the fiLm showed excellent static decay time, surface and volume resistivity, and resistance to water wash-out of additive and aging at elevated temperature.

EXAMPLE VIII(i) Coated samples of cardboard are prepared by laminating the fiLm of Example VIII thereto. These samples should exhibit excellent adhesion to a fiLm of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE IX

Quaternary amine QA1 ~5.O parts) was blended with Surlyn 1650 partially zinc neutralized ethylene-methacrylic acid-zinc methacrylate lonomer t23.7 parts) and LD318.92 ethylene-vinyl acetate copelymer ~71.3 parts). The blending and subsequent testing were carried out as described in Example VI. The results were as follows:

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

BeEore water Shower:
SDT (ms) 230 Surface Resistivity (ohms/square) 5.2 x 10``
Volume Resistivity (ohm-cm) 1.4 x l0'~
After 24-Hour water Shower:
SDT (ms) 150 Surface Resistivity (ohms/square) 6.S x 10'' Volume Resistivity (ohm-cm) 1.1 x 10'~
After 24-Hour Water Shower Followed bY lZ-DaY/70C Aqinq_ SDT (ms) ~o Surface Resistivity (ohms/square) 5.9 x 10'' Volume Resistivity (ohm-cm) 5.9 x 10t~
These results demonstrate that the film showed excellent static decay time, surface and volume resistivity, and resistance to water wash-out of additive and aging at elevated temperature.

EXAMPLE IX~i) Coated samples of cardboard are prepared by laminating the film of Example IX thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate lonomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE X

Quaternary amine QA6, N,N-dimethyl-N-ethyl-N-cocoammonium ethosulfate, was prepared as follows: 9.36 g of N,N-dimethylcocoamine was combined with 6.10 g of diethyl sulfate. After mixing at 80C for 2-3 minutes, a clear liquid was formed in an exothermic process. On cooling, a waxy solid ~m.p. 65-75C) resulted (QA6).

S/891227.3/SPECFLDR/01/10/90/02:59:47 PM
4~

,f.,,.:J ~

Quaternary amine QAs (4.44 9) was blerlded with 10 9 Dow Primacor 1410 (ethylene-acrylic acid copolymer, 9% ~A, 1.5 melt index) and 30 g Exxon LD318.9Z (ethylene-vinyl acetate copolymer, 9~ VA, 2.0 melt index). Blending was carried out in a Brabender Plasticorder mixer at l30C for 30 minutes. n sample oE the resultant material was pressed at approximately 1,000 psi ~70 kg/cm7) between platens heated to 150C. A
monolayer film of about 3 inches ~7.6 cm) by 5 inches (12.7 cm) by 0.00S
lnch ~0.01~ cm) was thus obtalned.

The surface resistivity of the sample was tested by two meth-ods: First, the sample was equilibrated at 12.5 +0.5~ RH for 48 hours and tested with a Keithley 6105 resistivity adapter ~Keithley Instru-ments, Cleveland, Ohio) connected to a Keithley 247 high voltage supply and a Keithley 485 picoammeter. With an applied voltage of 100 volts, a surface resistivity of 9.96 x 109 ohms/square was obtained. Second, the sample was equilibrated at 35 +S% RH Eor > 2 hours and tested with a TREX model 150 resistivity meter tTREK, Inc., Medina, NY). A surface resistivity of 9 x 10' ohms/square was obtained.

EXAMPLE X(i) Coated samples of cardboard are prepared by laminating the fiLm of Example X thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE XI

Quaternary amine QA6 (4.44 g) was blended with 10 g Surlyn 16S0 partially zinc neutralized ethylene-methacrylic acid-zinc methacrylate terpolymer and 30 9 Exxon LD318.92 as described in Example X.

When prepared and tested as described in Example X, a fiLm sample of this material gave the following results:

5/891227.3/SPECFLDR~01~10/90/02:S9:47 P~
~S

7~ 2 Surface Resistivity ater equilibration at 12.5 + o.5% RH ~or 48 hrs.: 2.00 x 10'~ ohms/squar~
Surface Resistivity after equilibratlon at 35 + 5% RH ~ 2 hrs.: 2 x 10~ ohmstsquare . .

EXAMPLE XI(i) Coated samples of cardboard are prepared by laminating the Eollowing film of thereto. These samples will exhibit excellent adhesion to a film of zinc methacrylate ionomer of EMAA when tested on an ~mpack skin packaging machine.

EXAMPLE XII

By blending with heat using a Berstorff twin screw extruder, a premix of pellets was made. First, 60 parts by weight EVA (LD318.92) and 30 parts by weight EAA (Primacor S981) were mixed, and then added thereto was 20 parts by wt. QA l Emerstat 6660]. The resultant EVA + EAA ~ QA was then further blended with more polymer, and hot blown, 5-layer, extruded, tubular film having a thickness of about 4 mil (0.102 mm) was made. The ingredients of each layer were as recited in Table XIIA and are in % by weight.

TABLE XIIA

OUTSIDE INTERIOR CORE INTERIOR OUTSIDE

LAYER lLAYER 2 LAYER 3 LAYER 4 LAYER 5 100~ EVA100% EVA100% LLDPE100% EVA 66-2/3~ EVA

33-1/3%

Mix of EVA+EAA~QA

5/891227.3/SPECFLDR/01/10/90/02: 59:47 PM

~I V . _ ~ ~ ' 7 ~) Then, the following electrical measurements were taken on samples oE ~ilm as ~eported in Table XIIB. R~slstivity was measured at ~bout 12.5 ~
2.5~ RH using a Keithley picoammeter with a separate 100 volt power source and an Electro Technical Services cell con~onming to ASTM D257. Testing ~or triboelectric charging was against aluminum plates.
TABLE XIIB
Abuse Treat-ment Static Decav Time (ms) or 1 Hr. 24 Hr. 48 Hr.
FilmOhms/squareOhms-cm Equili- Equili- Equili-TestedSurface Volume bration bration bration Tribo As isResistivityResistivity treatment treatment treatment Volts As is5.9 x 10'`1.8 x 10l~ 1852 1824 NT~ 86 24 Hr.1.9 x 10'~NT NT WON'T WON'T NT
Shower - ACCEPT ACCEPT
FULL FULL
CHARGE CHARGE
Hot Dry Oven Day 1 NT NT 2190 1722 NT NT
Day 2 NT NT 1492 3000 NT NT
Day 3 NT NT 1471 1398 NT NT
Day 4 NT NT 1326 1332 NT NT
Day 5 NT NT 1501 1453 NT NT
Day 6 NT NT NT NT NT NT
Day 7 NT NT NT NT NT NT
Day 8 NT NT NT NT NT NT
Day 9 NT NT NT NT NT NT
Day 10NT NT NT 1845 NT NT
Day 11NT NT NT 1794 NT NT
Day 122.0x10`72.3x10'~ ¦NT 15940 NT 537 ~NT = not tested 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM
~7 These results illustrate that after 11 days in a hot oven, the fiL~ exhibited an excellent SDT less than 2000 ms.

EXAMPLE XII(i) Coated sample~ of cardboard are prepared by laminating the fiLm o~ Exanple XII thereto. These samples should exhibit excellent adhesion to a film of zinc methacrylate lonomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE XIII

By blending with heat using a Berstorff twin screw extruder, a premix oE pellets was made. First, 60 parts by weight EVA ILD3l8.92] and 30 parts by weight EAA [Primacor 5981] were mixed, and then added thereto was 20 parts by wt. QA IEmerstat 6660J. The resultant mix of EVA ~ EAA
QA was then further blended with more polymer, and hot blown, 5-layer extruded, tubular film having a thickness of about 4 mil (0.102 mm) was made. The ingredients of each layer were as recited in Table XIIIA and are in % by weight.

Table XIIIA

OUTSIDEINTERIOR CORE INTERIOR OUTSIDE

66-Z~3% 66-2/3% EVA 100~ LLDPE 66-2/3~ EVA 66-2/3%
Primacor 1410 Prmacor 1410 33-1/3% ~ix33-1/3% Mix 33-1/3% Mix 33-1/3% Mix of EVAIEAA~QAof EVAIEAA~QA of EVAIEAA+QA of EVA~EAA~QA

Then, the following electrical measurements were taken on samples of film as reported in Table XIIIB. Resistivity was measured at about 12.5 ~
2.5~ RH using a Keithley picoammster with a separate 100 volt power source and an Electro Technical Services cell conforming to ASTM D257.
Testing for triboelectric charging was against aluminum plates.

5/89}227.3/SPECFLDR/01/10/90/02:59:47 PM

~ rJ ~ ~ 7 ~

TA~LE XIIIB

Abuse Treat-ment Static DecaY T~le (ms) or 1 Hr. 24 Hr. 48 Hr.
Film Ohms/square Ohms-cm Equili- Equill- Equili-Tested Surface Volume bration bration bratlon Tribo As ls Resistivitv Resistivity treatment treatment treatment Volts As is 1.3 x 10 '' 5.1 X 10 '~ 40 80 NT* 47 24 Hr. 7.9 x 10 ''NT NT 109 108 NT
Shower Hot Dry Oven Day 1 NT NT 217 185 NT NT
Day 2 NT NT 130 181 NT NT
Day 3 NT NT 68 64 NT NT
Day 4 NT NT 73 84 NT NT
Day 5 NT NT 86 88 NT NT
Day 6 NT NT 107 NT NT NT
Day 7 NT NT NT NT NT NT
Day 8 NT NT NT NT NT NT
Day 9 NT NT NT NT NT NT
Day 10 NT NT NT 84 NT NT
Day 11 NT NT NT 94 NT NT
Day 12 1~6xlO '' 2.1xlO `' NT 51 NT 56 *NT - not tested 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM
Aq . .

These results illustrate that after a 24-hour water shower and also aeter 12 days in a hot oven, the Eilm exhiblted both a permanent anti-statlc SDT less than 2000 ms and a permanent surface reslstivity in the an-tlstatic surface resistivity range of 10!1 to 10'~ ohms/square.

EXAMPLE XIII(i) Coated samples of cardboard are prepared by laminat~ng the film of Example XIII thereto. These samples should exhibit excellent adhesion to a fiLm of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE XIV

By blending with heat using a ~erstorff twin screw extruder, a premix of pellets was made. First, 60 parts by weight EVA lLD318.92¦ and 30 parts by weight EAA IPrimacor 5981l were mixed, and then added thereto was 20 parts by wt. QA [Emerstat 6660¦. The resultant mix of EVA ~ EAA +
QA was then further blended with more polymer, and hot blown, 5-layer, ex-truded, tubular film having a thickness of about 4 mil (0.102 mm) was made. The ingredients of each layer were as recited in Table XIVA and are in % by weight.

Table XIVA

OUTSIDEINTERIOR CORE INTERIOR OUTSIDE

56-2~3% 66-2~3% EVA 100% LLDPE 66-2/3% EVA 56-2/3%
Primacor 1410 Primacor 1410 33-1/3% Mix33-1/3~ Mix 33-1/3% Mix 33-1/3% Mix of EVA+EAA+QAof EVA+EAA+QA of EVA+EAA+QA of EVA+EAA+QA

10% Antiblock 10% Antiblock Then, the following electrical measurements were taken on samples of fiLm as reported in Table XIVB. Resistivity was measured at about 12.5 ~ 2.5%
RH using a Keithley picoammeter with a separate 100 volt power source and an Electro Technical Services cell conforming to ASTM D257. Triboelectric charging was tested against aluminum plates.

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

., ~J~ ; t i~ ~

TABLE XIVB

Abuse Treat-ment Stat~c DecaY Time (ms) _ _ or 1 Hr. 24 Hr. 48 Hr.
Fll~ Ohms~fiquare Ohms-cm Equili- Equili- Equlll-Tested Surface Volume br~tion bration bration Tribo As is Resistivity Resistivity treatment treatment treatment Volts As is 1.2 x 10 '' 5.8 x 10 ~3 11 31 NT~ 35 24 Hr. 6.6 x 10 '' NT NT 70 62 NT
Shower Hot Dry Oven Day 1 NT NT 40 26 NT NT
Day 2 NT NT 42 32 NT NT
Day 3 NT NT 41 40 NT NT
Day 4 NT NT 36 33 NT NT
Day 5 NT NT 52 42 NT NT
Day 6 NT NT 53 NT NT NT
Day 7 NT NT NT NT NT NT
Day 8 NT NT NT NT NT NT
Day 9 NT NT NT NT NT NT
Day 10 NT- NT NT 45 NT NT
Day 11 NT NT NT 44 NT NT
Day 12 1.6x10 1~ Z.4xl0 13 NT 65 NT 35 ~NT = not tested 5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

2 '~ ~ ' F~

These results illustrate that after a 24-hour water shower and also after 12 days in a hot oven, the fiLm exhibited both a permanent anti-static SDT less than 2000 ms and a permanent surface resistivity in the an-tistatic surface resistivity range of lO" to lO`' ohms/square.

EXAMPLE XIV(i) Coated samples of cardboard are prepared by laminating the fiLm of Example XIY thereto. These samples should exhibit excellent adhesion to a fiLm of zinc methacrylate ionomer of EMAA when tested on an Ampack skin packaging machine.

EXAMPLE XV

Primacor 5980 (900 g, 2.5 equiv. acrylic acid) and 25% aqueous tetramethylammonium hydroxide solution (866 ml, 2.38 equiv. hydroxide) were added to a 4-liter resin kettle containing 1567 ml distilled water.
Primacor 5980 is an ethylene acrylic acid supplied by Dow Chemical. It is 20% by wt. acrylic acid and 80~ by wt. ethylene, and has a melt index of 300. The mixture was mechanically stirred with heating at reflux for 7 hours, then cooled to room temperature. The resulting clear, viscou6 solu-tion was directly painted onto 3 1/2 x 5 inch coupons of Lexan R
polycarbonate. The coated coupons were equilibrated in a relative humidi-ty controlled chamber and then tested for surface resistivity at 12.5% and 50~ RH, and triboelectric charging against EVA fiLm. The results are re-ported in Table XV-A.

Table XV-A

Surface Resistivity Triboelectric Charging (ohm/sguare) volts (Avg of 4 tests) Sample 12.5% RH 50~ RH

1 g.24x109 5.0xlO~ 1263 2 NT ~ NT 465 3 (a) 1.61x10' NT NT
4 ~b) 2.18xlOI~ NT NT

5/891227.3/SPECFLDR/01/10/90/02:59:47 PM

3 ~ ~9 7 (a) Be~ore 12 day over~ aging (b) After 12 day oven aging The results show the coating per~ormed well as an antistatic coating in terms of surface resistivity, a~d was resistant to abusive aging.

EXAMPLE XV (i) Coated samples of corrugated cardboard were prepared on a roller-coating apparatus at three coating weights ~not quantified, but qualltatively designated "light", "medium", "heavyl'). These coated cardboard samples exhibited excellent adhesion, at all coating weights, to a film of zinc ionomer of EMAA when tested on an Ampack skin-packaging machine.

EXAMPLE XVI

The triboelectric properties of the coating mixture described in Example XV were improved by the addition of an enhancer. Two percent by weight of the additive was mixed at room temperature with the coating material. The resultant was directly painted onto 3 1/2 x 5 inch coupons of Lexan R polycarbonate. The coated coupons were equilibrated in a relative humidity chamber and then tested for surface resistivity at 12.S%
and 50% RH, and triboelectric testing against ~VA ~ilm. A representative series of enhancers and the test results are reported in Table XVI-A.

TABLE XVI-A

Additives Surface Resistivity Triboelectric Charging (ohms/sq) Against EVA film, Avg.
RH 12.5~ RH 50%of 4 trials ~Volts) Grou~ I

No Additive 9.Z4x109 5.0x1081263 Tween 20 8.38x109 3.01x107214 Stepanol WAT 4.32xlO9 1.76x107425 5/8912;!7.3/SPECFLI)R~01/10/90/02:59:47 PM

Glycerol 1.66x10~ 6.13x10~ 488 Ethylene Glycol 3.71x109 6.0xl0~ 500 Propylene Glycol l.33x10~ 4.47x10~ S44 Steol CA-460 1.58x109 4.07xl0~ 644 Tetraethylene Glycol 4.08x10~ l.79x10' 694 Bacote 20 1.45x10"' 2.67x10~ 694 Hexcel 106G 4.22x10~ 2.16x10~ 750 Calfax 10L45 3.93x10~ 8.75x10~ 819 GrouP II
No Additive - - 465 Tween 20 - - 18;56~
Pluronic L-62 9.30x109 1.51x10' 56;164R
Miranol OS-D 1.61x10~n 5.73x10' 84 Miranol CM-SF 8.98xl09 9.75x10~ 98 Amphoteric L l.65x101 3.58xl0 103 Dow Stature 6.13x109 1.56x10'133; 318*
Propylene Glycol - - 162 Stepanol DEA 2.02x10' n 1 . 99x 10 ~ 186 Glycerol - - 212 AO-14-2 6.56xl0~ 1.46xl0'322 Calfax 10L45 - - 325 Zonyl FSN 9.24xl0~ 8.12x10~372 AO-728 2.22xlo !n 1 . 65x10' 426 AO-14-2 6.56x10g 1.46x10'701 * Duplicate samples were tested.

It shoul-3 ~ noted that ~ se tribo values were not "exact"
numbers, as they dep~nd on a variety of factors. For example, the differences noted betwe ~ groups of samples show that coating thickness can make a difference; , I coatings were thicker than Group II. Also, if any pinholes of poly~a~ ate were exposed, a dramatic charging effec~
cou1d occur. Y1ewing each ~ r ~ n~moers independently, it becomes apparent that the addition of ~ertain enhancers improves the triboelectric charging properti~s of the coating relative to the original sample. The largest degree of improvement is seen with Tween 20, polyoxyethylene (20) S/891227.3/SPECFLDR/01/10/90/02:59:47 PM

3 ~ ~ 2 sorbitan monolaurate. Although some of the enhancers may also improve surface resistivity as well~ this improvement is not a deter~inant of their usefuln~s, and it does not correlate with triboelectric charging lmprovements.

EXAMPLE XVII
_ To further test the coatings o~ Examples XV and XVI, two small cardboard boxes were prepared. One was coated with the Example XV coating material and one with the Tween 20 enhanced formulation of ~xample XVI.
These boxes, and an uncoated box, were tested for surface resistivity, volume resistivity, static decay time, charge retention, and tribo charging against: solder masked circuit board, aluminum, ceramic integrated circuit and copper. See Table XVII-A.

TABLE XVII-A

Coated Coated Box Uncoated Box ~no (Tween 20 Box enhancer) enhancer) ~control) Surface Resistivity 50% RH 7.46x10~ 6.57x10~ 6.37x101l ~ohm/sq) 12.5% RH 1.45x10'1 2.03xl0'' 2.20x10'3 Volume Resistivity 50% RH 8.90x10'' 2.84xl0'` 4.72x10'~
~ohm/cm) 12.5% RH 4.91x10'Z 5.10x10~ 1.67xlO'~

Static Decay Time 50% RH 14 17 31 ~ms) 12.5% RH 895 902 1268 Tribocharging ~volts~

Solder Masked Circult Board 577 356 1061 Aluminum 4 3 84 Ceramic Integrated Circuit 694 384 117 Copper 4 3 -86 5/891227.3/SPECFLDR/01/10/90102:59:47 PM

'J ~

Charge retention ~residual voltage after 2000 volts applied) Seconds after elec- 1 sec o volts o volts l500 volts trically grounding 2 1 0 1200 the charged sample 3 o 0 ' 1000 4 0 0 ~00 0 o 600 These results indicate that both coated boxes were better than an uncoated cardbaard box, and further demonstrated the usefulness of the Tween 20 ethoxylated sorbitan ester as an enhancer for minimizing triboelectric charging.

EXAMPLE XVIII

In a similar fashion to Example XV, several anhydride-containing copolymers and carboxylic acid containing copoly~ers were reacted with either an organic or inorganic base in water. The resulting clear solutions we~e directly painted onto 3 1/2 inch x 5 inch coupons of Lexan R
polycarbonate. The coated coupons were equilibrated in a relative humidity controlled chamber at 12.S% RH and then tested for surface resistivity. The results are given in Table XVIII-A.

TABLE XVIII-A

Surface Resistivity Polvmer Base (ohms/sa) P5981 (5 9) TMAH.5H~0 (2.S2 9) 3.07xlO`' P5981 (5 g) TEAH (5.11 g, 40~ aq) 7.13x10l P5981 (5 g) Benzyltrimethyl Ammonium Hydroxide (5.81 9, 40% aq) l.lOx10`Z
P5981 (5 9) CsOH (4.16 9, 50% aq) 9.27x10``
P5981 (5 g) Triethanolamine (2.07 g) 2.16x10l1 P5981 (5 9) T8AH (6.55 g, 55% aq) 3.68x10`Z

5/891227.3/SPECFLDR/01/10/90~02:59:47 PM

f-? ~ q , '~' i, '~, SMA 1000 (5 9) Triethanolamine (7.38 9) 2.68xl0``
MA 100~ ~5 9) NaOH (1.03 9) 4.58x10``
CMA 1000 (5 9) KOH (1.40 9) 7.25x10'1 SMA l000 (5 9) CsOH (7.42 9, 50% aq) 9.08x10'' SMA 2000 (5 g) NaOH (0.625 9) 8.0x10'' SMA 1440 (5 9) NaOH ~0.67 9) 1.0xl0`~
SMA 1440 (5 g) TMAH ~5.70, 25% aq) 3.0xl0'' SMA 2625 ~5 9) NaOH (.79 9) 6.0xl0' SMA 262S (5 9) TMAH (7.16 9, 25~ aq) 3x10"' SMA 17352 (5 9) NaOH (0.964 9) 1x10'~
SMA 17352 ~5 g) TMAH ~8.79 g, 25~ aq) 1x10'~

Allied AC143 ~5 g) TMAH (1.94 g, 25% aq) 7.32xlO

EXAMPLE XIX

EPG-112 has been ~ommercially available from the Cryovac Division of W.R. Grace ~ Co.-Conn. EPG-112 was a coextruded, hot blown, 5-layer symmetric ~ilm of the structure: A/B/C/B/A made in thicknesses of 2.0, 3.0, and 4.0 mils, where the percentages recited below were in ~ by weight.

LaYer A: ComPosed of EYA, EAA, antiblock, antistatic a~ent EYA: 30~ of LaYer A

Density: 0.929 to 0.931 g/ml VA Content: 9.0 + 0.5~
Melt Index: l.8 to 2.2 g/10 min., ASTM D-1238 EAA: 52.5~ of LaYer A

Density: 0.938 g/ml Acrylic Acid Content: 9.5~
Vicat So~tening Point: 180F
Melt Index: 1.5 + 0.5 g/10 min., ASTM D-1238 5/891227.3/SPECFLDR/01/12/90/08:21:51 ~M

Antiblock Masterbatch - Silica Dispersion in PolYethylene:
10~ of Layer A

Density of Antiblock Masterbatch: 0.96 to 0.9B g/ml Melting Point of Masterbatch: Unknown Silica Content: 10%
Melt Index of Masterbatch: 3.90 to 4.14 g/10 min., ASTM

Antistat: Modified Sova Dimethvlethlammonium Ethosulfate:
7.5% of Laver A

Density of Antistat: 1.005 g/ml @Z5C
pH 35% Solution in Water: 6.0 - 6.9 @25C
Boillng Point: >300F
Melting Point: 120F

Laver B: _Co~osed of EVA, F,AA, and Antistatic Aqent EVA: 67% of Laver B
Same EVA as layer A

EAA: 24.7~ of laver 8 Same EAA as layer A

Antistatic Aaent: 8.3% of laver B
Same antistatic agent as layer A

Laver C: ComPosed of LLDPE, EAA, Antistatic Aqent LLDPE: 90% of laver C

Density: 0.918 to 0.922 g/ml Melting Point: 123 - 126C, DSC 2nd heat Melt Index; 1.1 + 19/10 min.
Octene Comonomer Content: 6.5 ~ 0.5%

5/891227.3/SPECFLDR/01~12/90/08:21:51 AM

,i, Q-) Q~

~AA: 7.5~ of layer C

Same F.AA as layer A

Antistatic Aqent: 2.5~ of layer C

Same antistatic agent as la~er A

EXAMPLE XIX~i) Coated samples of cardboard were prepared wherein the film of Example XIX, namely 4 mil EPG-112 was then adhesively laminated to cardboard using a dextrin adhesive (the ordinary "paper-to-~paper" dextrin adhesive is commercially available under the tradename Dextrin 12-0095 from National Starch). Subsequently, a one-inch wide sample was cut, and with the aid of solvents, the EPG-112 was separated from the cardboard for a distance of about one inch with the remainder of the sample strip staying bonded, the separated portions Eorming grip tabs. After the solvent had been suf ficiently dried and removed from the samples so that it would not affect the results, one tab was placed in one jaw of an Instron test machine and the other tab in the other jaw. ~he jaws were then separated and the threshold force to pull the layers apart recorded.
At a draw rate of 5 inche~/minute, at 73F, this was 0.42 pounds. These samples exhibited excellent adhesion to the cardboard.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

5/8912~7.3/SPECFLDR/02/15/90/01 :n5:24 PM

Claims (19)

1. A semi-rigid heat-sealable, laminate with permanent anti-static characteristics comprising a semi-rigid deformable substrate having a surface with a surface portion for supporting an item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bond-ed to said surface, said layer including a modified acid copolymer select-ed from:

(I) a mixture of (A) a polymer containing carboxyic acid moieties and (B) an antistatically effective amount of a quaternary amine;

or from (II) an acid/base reaction product of (A) a polymer containing carboxylic acid moieties and (C) an antistatically effective amount of an organic or inorganic base wherein:

(A) the polymer containing carboxylic acid moieties is a copolymer of (i) an alpha-olefin of the formula RCH=CH2 wherein R is H or C1 to C20 alkyl, C1 to C20 alkoxy, or C5 aryl, and (ii) an alpha,beta-ethylenically unsaturated carboxylic ac-id, and (B) the quaternary amine is of the formula [(R1)(R2)(R3)(R4)N]+ [X]-wherein 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

R1 is selected from H, aryl, or C1 to C50 alkyl optionally having one or more non-contiguous C=O or NHC=O or -S- or -O- in the carbon chain, or the same as R2;

each of R2, R3, and R4 is the same or different and selected from H, C1 to C18 alkyl optionally substitut-ed with one or more OH or from -(R5-O)n-H where a is an integer from 1 to 10 and R5 is ethylene or propylene;

and X is an anion selected from chloride, bromide, iodide, fluoride, nitrate, fluoborate, phosphate, C1 to C2O
alkyl phosphate, sulfate, C1 to C20 alkyl sulfate, formate, C1 to C20 alkyl or C1 to C24 alkaryl or aryl sulfonate, acetate, trifluoroacetate, citrate, propionate, or tartrate, and (C) the organic or inorganic base is of the formula [M]+[Y]-, wherein [M]+ is selected from Li+, Na+, K+, Rb+, Cs+, or R6R7R8R9N+, where R6, R7, R8, and R9 are independently selected from a C1 to C4 alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, and [Y]- is selected from hydroxide, C1 to C4 alkoxide, bicarbonate, or carbonate.

2. The laminate of claim 1 wherein the polymer containing carboxylic acid moieties is ethylene-acrylic acid or ethylene-methacrylic acid and the quaternary amine is of the formula wherein: R1 is C4 to C30 alkyl, straight or branched optionally including one or more ether linkages and each of R2, R3and R4 is the same or different and se-lected from methyl or ethyl, and X is chloride, methyl sulfate, ethyl sulfate, methanesulfonate, or toluenesulfonate.

3. The laminate of claim 1 wherein the polymer containing carboxylic acid moieties is ethylene-acrylic acid or ethylene methacrylic 5/891227.3/SPECFLDR/03123/90/10:36:33 AM

acid and the organic or inorganic base is of the formula wherein [M]+ is K', Cs', or [R6R7R8R9N]' wherein R6, R7, R8 and R9 are selected from methyl, ethyl, or C2H4OH, and [Y]- is hydroxide, methoxide, or ethoxide.

4. The laminate of claim 1 wherein the antistatic layer will exhibit polycarbonate compatibility and be free of causing crazing of polycarbonate at a stress condition of at least about 2500 psi (176 kg/cm2) and 120°F (48.9°C).

5. The laminate of claim 1 wherein said laminate has the form of an X with a center including said surface portion, opposing first and second arms, each of said first and second arms foldable over said center or over the other arm of said first and second arms when said other arm is folded over said center, a third arm with a slotted opening, said third arm foldable over said center and said first and second arms when said first and second arms are folded, a fourth arm opposing said third arm and foldable over said third arm when said third arm is folded over said cen-ter and said first and second arms, and a tab on said fourth arm for being received into said slotted opening to releasably close said package when said fourth arm is folded over said third arm.

6. A package constructed from the laminate of claim 1 wherein said surface includes a continuous border portion surrounding said surface portion, and when a static-sensitive item is placed on said surface por-tion to be packaged, said package further includes a sheet of flexible, heat-sealable, antistatic film vacuum formed over said surface portion and bonded to the portion of said anti-static layer extending over said border portion to form an enclosure over said surface portion, which con-tains the static sensitive item.

7. The laminate of claim 1 wherein the polymer containing carboxylic acid moieties is an ionomer containing carboxylic acid moieties partially neutralized by a metal salt.

8. The laminate of claim 1 wherein the antistatic layer will dissipate an applied charge of ?5000 Vdc in a static decay time less than 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

about 3000 milliseconds and will have a surface resistivity from about 105 to about 1012 ohms/square.

9. The laminate of claim 8 wherein the static decay time is less than about 3000 milliseconds and the surface resistivity is from about 105; to about 1012 ohms/square, after a 24 hour water shower.

10. The laminate of claim 8 wherein the static decay time of less than about 3000 milliseconds and the surface resistivity is from about 105; to about 1012 ohms/square, after 12 days in a hot oven of about 70°C.

11. A semi-rigid heat-sealable laminate with permanent anti-static characteristics comprising a semi-rigid deformable substrate having a surface with a surface portion for supporting an item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bond-ed to said surface, said layer being resultant from mixing with heat, op-tionally with solvent, (A) a polymer containing carboxylic acid moieties and an antistatically effective amount of a modifier selected from either (B) a quaternary amine or (C) an organic or inorganic base wherein:

(A) the polymer containing carboxylic acid moieties is a copolymer of (i) an alpha-olefin of the formula RCH=CH2 wherein R is H or C1 to C20 alkyl, C1 to C20 alkoxy, or C6 aryl and (ii) an alpha,beta-ethylenically unsaturated carboxylic ac-id, and (B) the quaternary amine is of the formula [(R1)(R2)(R3)(R4)N]+ [X]-wherein R1 is selected from H, aryl, or C1 to C50 alkyl optionally having one or more non-contiguous 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

C=O or NHC=O or -S- or -O- in the carbon chain, or the same as R2;

each of R2, R3, and R4 is the same or differ-ent and selected from H, C1 to C18 alkyl option-ally substituted with one or more OH or from -R5-O)?-H where a is an integer from 1 to 10 and R5 is ethylene or propylene;

and X is an anion selected from chloride, bromide, iodide, fluoride, nitrate, fluoborate, phosphate, C1 to C8 alkyl phosphate, sulfate, C1 to C8 alkyl sulfate, formate, C1 to C8 alkyl or C6 to C24 alkaryl or aryl sulfonate, acetate, citrate, trifluoroacetate, propionate, or tartrate, and (C) the organic or inorganic base is of the formu la [M]+[Y]-, wherein [M]+ is selected from Li+, Na+, K+, Rb+, Cs+, or R6R7R8R9N+, where R6, R7, R8, and R9 are independently selected from a C1 to C4 alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, and [Y]- is selected from hydroxide, C1 to C4 alkoxide, bicarbonate, or carbonate.

12. A semi-rigid, heat-sealable laminate with permanently anti-static characteristics comprising a planar, semi-rigid deformable sub-strate having a surface with a surface portion for supporting an item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bonded to said surface, said layer obtained from mixing with heat, optionally with solvent, ethylene-acrylic acid or ethylene-methacrylic acid and a quaternary amine of the formula [(R1)(R2)(R3)(R4)N]+ [X]- where R1 is a C4 to C30 straight or branched alkyl optionally including one or more ether linkag-es, each of R2 and R3 and R4 is the same or different and selected 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

from methyl or ethyl, and X is chloride, methyl sulfate, ethyl sulfate, methane sulfonate, or toluene sulfonate.

13. A semi-rigid, heat-sealable laminate with permanently an-tistatic characteristics comprising a planar, semi-rigid deformable sub-strate having a surface with a surface portion for supporting an item to be packaged, and a heat-sealable, permanently antistatic layer extending over and bonded to said surface, said layer obtained from mixing with heat, optionally with solvent, ethylene-acrylic acid or etylenemethacrylic acid and an organic or inorganic base of the formula [M]+[Y]- where [M]+ is K', Cs', or [R6R7R8R9N]+ wherein R6, R7, R8, and R9 are selected from methyl, ethyl, or C2H4OH, and [Y]- is hydroxide, methoxide, or ethoxide.

14. A package according to claim 12, wherein the permanently antistatic layer will, after a 24 hour water shower, after 12 day oven ag-ing at 70°C, or after both, dissipate an applied charge of ?5000 Vdc in less than about 3000 ms without having being subjected to irradia-tion from an electron beam.

15. A package according to claim 13, wherein the permanently antistatic layer will, after a 24 hour water shower, after 12 day oven ag-ing at 70°C or after both, dissipate an applied charge of ? 5000 Vdc in less than about 3000 ms.

16. A method for making a semi-rigid, antistatic, heat-seal-able laminate with permanent antistatic characteristics comprising (1) modifying an acid copolymer by mixing with heat, op-tionally with solvent, (A) a polymer containing carboxylic acid moieties and an antistatically ef-fective amount of a modifier selected from either (B) a quaternary amine or (C) an organic or inorgan-ic base wherein:

(A) the polymer containing carboxylic acid moieties is a copolymer of (i) an alpha-olefin of the formula RCH=CH2 wherein R is H or C1 to C20 alkyl, 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

. . .

C1 to C20 alkoxy, or C6 aryl, and (ii) an alpha,beta-ethylenically unsaturated carboxylic ac-id, and (B) the quaternary amine is of the formula [(R1)(R2)(R3)(R4)N]+ [X]-wherein R1 is selected from H, aryl, or C1 to C50 alkyl optionally having one or more non-contiguous C=O or NHC=O or -S- or -O- in the carbon chain, or the same as R2;

each of R2, R3 and R4 is the same or differ-ent and selected from H, C1 to C16 alkyl option-ally substituted with one or more OH or from -(R5-O)?-H where a is an integer from 1 to 10 and R5 is ethylene or propylene;

and X is an anion selected from chloride, bromide, iodide, fluoride, nitrate, fluoborate, phosphate, C1 to C8 alkyl phosphate, sulfate, C1 to C8 alkyl sulfate, formate, C1 to C8 alkyl or Cy to C24 alkaryl or aryl sulfonate, acetate, citrate, trifluoroacetate, propionate, or tartrate, and (C) the organic or inorganic base is of the formu-la [M]+[Y]-, wherein [M]+ is selected from Li+, Na+, K+, Rb+, Cs+, or R6R7R8R9N+, where R6, R7, R8, and R9 are independently selected from a C1 to C4 alkyl, benzyl, 2-hydroxyethyl, or hydroxypropyl, 5/891227.3/SPECFLDR/03/23/90/10:36:33 AM

and [Y]- is selected from hydroxide, C1 to C4 alkoxide, bicarbonate, or carbonate, and (2) applying a layer of said modified acid copolymer/quaternary amine mixture to a sheet of semi-rigid substrate.

17. The method of claim 16, wherein said layer is a permanent-ly antistatic film which will, after a 24-hour water shower, after a 12 day oven at 70°C, or after both, dissipate an applied charge of ?5000 Vdcin less than about 3000 milliseconds.

18. The laminate of claim 1 wherein a triboelectric enhancer is present in the antistatic layer.

19. The laminate of claim 18, wherein said triboelectric enhancer is comprised of ethoxylated sorbitan ester, ethoxylated glycerol ester, coco amphopropionate, oleoamphopropyl sulfonate, or ethylene oxide propylene oxide copolymer.

5/891227.3/SPECFLDR/03/23/90/10:36:33 AM