JPH0336023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat laminating a sealant web to a polyvinylidene chloride (PVDC)-coated base film.

Laminates of base films and sealant webs with PVDC coatings sandwiched between them are useful for packaging food products such as bacon, sausages, and cheese. Examples of base films are nylon film, polyester film and polypropylene film,
And an example of a sealant web is polypropylene. Typically, such laminates consist of a PVDC coated base film with a sealant web.
Produced by laminating to a PVDC coating, so-called adhesive lamination. Typically in such adhesive lamination methods, an adhesive dissolved in a solvent is spread onto the PVDC coating and the solvent is evaporated to make the adhesive tacky. The sealant web is then pressure laminated to the tacky adhesive coated PVDC. The adhesive is usually a urethane adhesive. Such urethanes can be dissolved in volatile organic solvents such as acetone, ethyl acetate or toluene.

Adhesive lamination of sealant webs to PVDC coatings has several drawbacks. One drawback is that they tend to be highly flammable,
Concerns the use of volatile organic solvents, which are expensive and not easily recoverable. Therefore, from a safety standpoint, it is desirable to use a water-based adhesive or an adhesive-free method. Another drawback concerns the types of PVDC that can be used. Crystalline PVDC must be used to prevent PVDC from being attacked by the solvents used in the adhesive lamination process. However, crystalline PVDC generally does not adhere well to the aforementioned base films, and it is usually necessary to bond the crystalline PVDC to the base film with a primer. For example, amorphous PVDC primer
No. 391235 (TJ Lang, filed December 1981), the nylon film is
Can be used to bond to PVDC.

Another technique for producing a laminate of two plastic films with PVDC sandwiched between them is to
Coating with a PVDC barrier and then heat laminating the second film to the barrier adhesive. The barrier adhesive is an oriented polypropylene film, medium density polyethylene (approximately 0.935-0.945
g/cm ³ ), nitrocellulose-coated regenerated cellulose and nylon films are available for coating. Such barrier adhesives are said to be heat laminable to low density polyethylene films. However, bonding using so-called slip-modified low-density polyethylene films, i.e. low-density polyethylene films containing slip adhesives, yields only about 10 to 20 g/l as measured on a Suter™ tester.
It turned out to be cm. Commercially acceptable bond strengths are greater than about 100 g/cm.

It consists of a first sealant web and a base film, the base film is a nylon film, an oriented polypropylene film, an oriented polyester film, or a second sealant web, and between the first sealant web and the base film
Laminates and methods for making laminates have now been discovered that have a PVDC layer, do not rely on adhesive lamination methods, and have commercially acceptable bond strengths.

Accordingly, the present invention provides a film laminate comprising a base film and a first sealant web with a PVDC coating therebetween, the first sealant web comprising: (a) ethylene and vinyl acetate; A film made from a copolymer of
and (b) (1) a copolymer of ethylene and vinyl acetate and (2) a homopolymer of ethylene, or a copolymer of ethylene and one or more C ₄ -C ₁₀ α-olefins, said homopolymer or copolymer being having a density of about 0.915 to about 0.955 g/cm ³ , or a blend of said homopolymer and copolymer, said base film is an oriented nylon film, an oriented polyester film. a second sealant web selected from the group consisting of a film, an oriented polypropylene film, a cast nylon film, and a second sealant web selected from the same group as the first sealant web and having a slip coefficient of less than about 0.4; The PVDC coating consists of at least one layer, said layer has a crystallinity of less than 1.15 when dried and left for 30 days at 20° C., and the base film is selected from nylon film, polyester film or polypropylene film. , when the layer in contact with the base film is dried and left at 40°C for 50 days, 1.12~
A film laminate is further characterized by having a crystallinity of 1.25.

The present invention also provides that the base film and the first sealant web are fed together between a nip roll and a hot roll, and the PVDC coating is applied to at least the base film or the first sealant web, but the PVDC coating is applied to at least the base film or the first sealant web. A method of forming a laminate according to the present invention, characterized in that when the second sealant web is in contact with the hot roll, said web in contact with the hot roll has a slip coefficient of less than about 0.4. do.

In one embodiment, the method comprises: (a) a PVDC coated base film or a first
(b) passing the heated PVDC coated base film or first sealant web over a hot roll; c) When using a PVDC coated base film, a first sealant web is brought into contact with the PVDC coating and between a nip roll and a hot roll said first sealant web is coated with PVDC.
When sandwiching against a coated base film to form a laminate and using a PVDC coated base film, the base film is brought into contact with the PVDC coated base film between a nip roll and a hot roll to form a laminate. to form, to consist of.

In another embodiment of this method, a PVDC coated base film first sealant web is taken and a further PVDC coating is applied to the base film or first sealant web, followed by heat lamination to form a laminate. Specific embodiments are designated hereinafter as Methods A, B, C and D.

Method A consists of: (a) coating a PVDC coated base film with a PVDC coated base film;
When heated to a sufficient degree to reduce the crystallinity of the coating to less than about 1.05, the PVDC is dried and allowed to stand at 20° C. for 30 days;
Characterized by having a crystallinity of less than 1.15 and when the base film is selected from nylon film, polyester film or polypropylene film, the PVDC coating has a crystallinity of 1.12 to 1.12 when dry and left standing at 40°C for 50 days. (b) The PVDC coated base film is further characterized by having a crystallinity of 1.25.
coating with a PVDC dispersion to form a second PVDC coating, said PVDC coating characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40° C. for 5 days; (c) Dry and then apply a second PVDC coating until the temperature of the free surface of said second coating is
(d) passing the resulting PVDC coated base film over a hot roll, said base film being in contact with said hot roll, and said hot roll having a temperature above about 70°C; and (e) contacting the first sealant web with a second PVDC coating and applying the PVDC coating to the first sealant web between a nip roll and a hot roll.
It consists of sandwiching it against a coated base film to form a laminate.

Method B consists of: (a) coating a PVDC coated base film with a PVDC coated base film;
When heated to a sufficient degree to reduce the crystallinity of the coating to less than about 1.05, the PVDC is dried and allowed to stand at 20° C. for 30 days;
Characterized by having a crystallinity of less than 1.15 and when the base film is chosen from nylon film, polyester film or polypropylene film, the PVDC coating has a crystallinity of 1.12 to 1.12 when dry and left at 40°C for 5 days. (b) a first sealant web having a surface tension of at least 42 dynes/cm, coated with an aqueous PVDC dispersion to form a PVDC coated first sealant web; , the PVDC coating on the first sealant web is characterized by having a crystallinity of less than 1.15 when dry and left undisturbed for 30 days at 20°C; (c) the PVDC coating on the first sealant web; (d) passing a PVDC coated base film over a heated roll, said base film being in contact with said heated roll, said heated roll being at a temperature greater than about 70°C; and (e) PVDC coated first sealant web
contacting the PVDC surface with the PVDC surface of the PVDC coated base film and sandwiching the PVDC coated sealant web against the PVDC coated base film between a nip roll and a hot roll to form a laminate. .

Method C is: (a) PVDC coated first sealant web water based
coating with a PVDC dispersion to form a second PVDC coating, said second PVDC coating characterized by having a crystallinity of less than 1.15 when dried and left at 20° C. for 30 days; is selected from nylon film, polyester film or polypropylene film,
The 2PVDC coating is further characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40°C for 5 days, and the PVDC coating adjacent to the first sealant web is
The coating is characterized by having a crystallinity of less than 1.15 when dried and left undisturbed for 30 days at 20°C; (b) the second PVDC coating is dried; (c) the base film is placed above the hot roll (d) contacting the base film with a second PVDC coating and between the nip roll and the heat roll; (d) contacting the base film with a second PVDC coating; and sandwiching the base film against a PVDC coated first sealant web to form a laminate.

Method D consists of: (a) coating a base film with an aqueous PVDC dispersion; the resulting coating is dried and
The PVDC coating is characterized by having a crystallinity of less than 1.15 when left standing for 30 days at 20°C, and when the base film is chosen from nylon film, polyester film or polypropylene film, the PVDC coating is dried and heated at 40°C. (b) drying the PVDC coating; (c) passing the PVDC coated base film over a hot roll; The base film is in contact with the hot roll, and the hot roll is about
and (d) a PVDC coated first sealant web.
The PVDC coated surface is brought into contact with the PVDC coated surface of the PVDC coated base film, and between the nip roll and the hot roll,
sandwiching a PVDC coated sealant web against a PVDC coated base film to form a laminate.

In a further embodiment of this method, taking the base film or first sealant web;
After applying the PVDC coating to the base film and/or the first sealant web, a laminate is formed by heat lamination.

Method E consists of: (a) coating the base film with a first PVDC; the coating is dried and heated at 20°C for 30°C;
Characterized by having a crystallinity of less than 1.15 and when the base film is chosen from nylon film, polyester film or polypropylene film, the PVDC coating dries and has a crystallinity of 40
(b) coating the PVDC coated base film formed in step (a) with a second PVDC; (c) forming a second coating, the second coating being characterized by having a crystallinity of less than 1.15 when dry and standing at 20°C for 30 days; (d) passing the resulting PVDC coated base film over a hot roll, said base film being in contact with said hot roll; and said hot roll is at a temperature greater than about 70° C., and (e) contacting a sealant web with a second PVDC coating and sandwiching said sealant web against a PVDC coated base film between a nipple roll and a hot roll. consisting of forming a laminate.

Method F includes: (a) coating a first sealant web having a surface tension of at least 38 dynes/cm with a first PVDC to form a first PVDC coating;
(b) the PVDC-coated first sealant web formed in step (a) is coated with a second PVDC-coated sealant web; the second coating is characterized by having a crystallinity of less than 1.15 when dried and left for 30 days at 20°C, and the base film is selected from nylon film, polyester film or polypropylene film. When the second PVDC coating is dried and left at 20°C for 30 days,
has a crystallinity of less than 1.15 and is dry and
1.12 to 1.25 when left at 40℃ for 5 days
(c) passing a base film over a heated roll, said base film being in contact with said heated roll, and said heated roll having a crystallinity of greater than about 70°C; (d) the PVDC formed in steps (a) and (d);
contacting the PVDC coated surface of the coated first sealant web with the base film;
The process consists of sandwiching a PVDC coated first sealant web against a base film between a nip roll and a hot roll to form a laminate.

Method G consists of: (a) coating the base film with a first PVDC; the coating is dried and heated at 20 °C for 30
The first PVDC coating is characterized by having a crystallinity of less than 1.15 when left to stand for 5 days, and the base film is selected from nylon film, polyester film or polypropylene film. When left still, 1.12~
(b) drying the first PVDC coating; (c) coating the first sealant web with a second PVDC having a surface tension of at least 42 dynes/cm; the coating is characterized by having a crystallinity of less than 1.15 when dried and left undisturbed at 20°C for 30 days; (d) drying the second PVDC coating; (e) placing the base film above the hot roll; (e) the base film is in contact with the hot roll, the hot roll being at a temperature greater than about 70°C, and (e) the PVDC coated first sealant web is
contacting the PVDC surface with the PVDC surface of the PVDC coated base film and sandwiching the PVDC coated sealant web against the PVDC coated base film between a nip roll and a hot roll to form a laminate. .

In a preferred embodiment of the method of the invention, the PVDC layer in contact with the base film and the PVDC layer furthest from the base film are combined into a single layer, and when said PVDC layer is dried and left to stand at 20°C for 30 days, has a crystallinity of less than 1.15;
and is further characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40°C for 5 days.

In other embodiments, when the base film is a cast nylon film, the PVDC coating furthest from the base film, i.e.
The layer containing the sealant web is dried and
It is characterized by having a crystallinity of less than 1.05 when left standing for 30 days at ℃.

In particularly preferred embodiments, the first sealant web comprises (a) a copolymer of ethylene and vinyl acetate, and (b) a copolymer of ethylene and vinyl acetate, and (1) ethylene and a _C4 - _C10 alpha-olefin. copolymer, said copolymer is about 0.915
(2) a homopolymer of ethylene, a blend with said ^homopolymer , or said homopolymer has a density of from about 0.915 to about
of a material selected from the group consisting of a blend with at least one of: having a density of 0.955 g/ ^cm3 ;
having a surface adjacent to a PVDC coating.
Preferred copolymers of ethylene and alpha-olefin are ethylene/butene-1, ethylene/octene-1 and ethylene/butene-1/octene-1.
It is a copolymer of No. 1.

Preferably, the vinyl acetate content of the ethylene and vinyl acetate copolymer (EVA) is from about 1.0 to about 20
The weight ratio of copolymer of ethylene and vinyl acetate to homopolymer of ethylene, copolymer of ethylene or blend of said copolymer and homopolymer ranges from 2:98 to 50:50.

In other embodiments, the sealant web is about
EVA with vinyl acetate content from 1.0 to about 15% by weight
copolymer and the sealant web contains a slip additive. The slip coefficient of the sealant web is less than 0.4, especially less than 0.3, as determined by ASTM method D-1894.

In yet other embodiments, the surface of the sealant web adjacent to the PVDC coating is corona discharge treated to a level of 38-45 dynes/cm prior to lamination.

In another preferred embodiment, the base film is a nylon film, especially nylon-6,
A film of nylon-66, or a condensation copolymer of ε-caprolactam and hexamethylene diamine adipate (sometimes called nylon 6/66).

In a further preferred embodiment, the base film is a metal coated surface, said surface being between the base film and the PVDC coating. The coating is a metal foil or
For example, vacuum deposited film.

In other embodiments, the base film is a copolymer of ethylene and vinyl acetate that is bonded to the carrier web and has a vinyl acetate content of 2 to 40% by weight. Preferably the carrier web is made from an ionomer.

In another embodiment, the base film has an aluminum-coated surface, said surface being sandwiched between the base film and the PVDC coating.

In still other embodiments, the PVDC layer is
The intervening PVDC layer interposed between the first PVDC coating and the second PVDC coating is characterized by being able to exhibit crystallinity, and the level of the intervening crystalline PVDC layer thus formed is as described below. It is such that it resists attack by organic solvents, as measured by the Solvent Haze Test, and said organic solvents are capable of dissolving PVDC coatings with a crystallinity of less than 1.05. An example of a PVDC dispersion suitable for forming the intervening layer is available under the trademark Serfen411.

In the solvent haze test, PVDC
After the coating has been dried and crystallized, it is sprayed with an organic solvent. If the PVDC coating has developed sufficient crystallinity, it will not be affected by the solvent.
However, when the crystallinity of the PVDC coating is insufficient, the solvent will cloud the appearance of the PVDC coating or dissolve a portion or all of the PVDC coating.

Crystallinity, as defined herein, is measured using infrared spectroscopy by obtaining an attenuated total internal reflection infrared spectrum of the coated film. Crystallinity can be measured using a Perkin Elmer(TM) 467 infrared spectrometer and a Wilks(TM) ATR-9 attenuated total internal reflection apparatus with the germanium crystal section at 45 degrees. In this method, a rectangular film is placed on each side of a germanium crystal (ie, two rectangular films are used), with the PVDC coated side of the film facing the crystal. Reference beam attenuator at 1150 cm ^-1 85
% and scan the sample from 950 cm ^-1 to 1150 cm ^-1 . The background absorption A is measured at 1115 cm ^-1 and at the peak, at 1070 cm ^-1 and 1042 cm ^-1 . Crystallinity is calculated by dividing the difference between A ₁₀₄₂ and A ₁₁₁₅ by A ₁₀₇₀ and A ₁₁₁₅ .

The following description of the invention relates to coating and laminating nylon base films. Techniques similar to those used for nylon films, particularly oriented nylon films, can be used for polyester and polypropylene base films. However, cast nylon films, especially thin cast nylon films, require more stringent controls when coating with PVDC and laminating PVDC coated nylon films to sealant webs due to the sensitivity of cast nylon films to moisture and heat. shall be. Base films made from sealant webs require a slip coefficient of less than about 0.4 to prevent the film from sticking to the hot roll.

The invention will now be described with reference to the accompanying drawings.

Referring to FIG. 1, suitable equipment includes a first coating station 10, a first dryer 1
1, a second coating station 12, a second dryer 13, and a nip roll assembly 14. The equipment for supplying the base film and sealant web and winding the laminate is
Not shown.

The first coating station 10 is a PVDC
It consists of a pan 34 for holding the dispersion, a direct gravure roll 16, and a nip roll 20 associated with the gravure roll 16. The second coating station 12 is similar to the first coating station 10 and includes a pan 35 and a direct gravure roll 1.
7 and nipprole 21. Instead of direct gravure rolls 16 and 17 and associated nip rolls, Meyer™ rods, reverse gravure rolls or other coating equipment can be used. When using equipment that subjects the PVDC dispersion to relatively high shear, the PVDC dispersion is modified, eg, isopropyl alcohol is added, to minimize foaming.

The nip roll assembly 14 includes a lamination roll 18, which has heating means (not shown), and a lay-on roll 36, which can guide the PVDC coated nylon film onto the lamination roll 18. Aeon roll 37, which allows the sealant web to be guided into the nip between the nip roll 19 and the lamination roll 18, and a take-off roll 38, which allows the laminate to be guided between the lamination roll 18 and the nip roll 19. After passing through the nip, the laminate is rolled into lamination roll 1.
8 and can be positioned such that it can remain in contact with the 8.

There are various idler rollers (some shown in the figure but not identified);
For example, after leaving the first coating station 10 and at the second coating station 12,
The film can be guided through a first dryer 11 before going there.

In one embodiment, the nylon film 3
0 to the first coating station 10. The first coating station includes a direct gravure roll 16 and an associated nip roll 2.
Consists of 0. A first PVDC coating is applied at a first coating station. Typically, if the nylon film is oriented, it will weigh between ² and 4 pounds per ream.
PVDC coating i.e. 6.50~13.02g/
m ² of 50% PVDC dispersion, and if the nylon film is substantially unoriented, i.e. cast nylon film, 2.44
~3.25g/ ^m2 PVDC coating, i.e.
A 50% PVDC dispersion of 4.88 to 6.51 g/m ² is applied. After drying the second PVDC coating in the first dryer 11, it is coated with a second PVDC coating in the second coating station. Typically, 3.25 to 6.51 g/m of PVDC coating is gravure coated directly onto the PVDC coated film by a direct gravure roll 17 and associated nip roll 21. Even cast nylon film has a weight of 6.51g/m at this stage.
Can be coated with up to or more PVDC coatings. This is because the first PVDC coating prevents water in the PVDC dispersion from causing wrinkle formation or bowing of the nylon film. The second PVDC coating is dried in the second dryer 13. 2nd dryer 1
3, the amount of heat applied to the PVDC coated nylon film is such that the second PVDC coating is sufficiently dry and has sufficient so-called "green tack", but the relatively non-tacky skin film is It is controlled to ensure that it is not heated to the extent that it forms on the PVDC coating.

"Green Tactic" used in this field
The term may be a misnomer. This is because it is believed that dried PVDC coatings are not tacky in the normally accepted sense of the word. This term refers to PVDC
It is believed to be related to a lack of bridging in the coating. In this method, the validity of the GreenTack designation may be confirmed by measuring the surface temperature of the PVDC coating just before the PVDC coated film leaves the second dryer. At surface temperatures below about 70°C, PVDC coatings have sufficient green tack for subsequent lamination. about 70
At temperatures higher than ℃, e.g. 85℃,
The PVDC coating has sufficient green tack for the PVDC coating to be able to adhere well to the sealant web. The PVDC coated nylon film 31 coming out of the second dryer 13 is transferred to a heated lamination roll 18.
The nylon film contacts the roll 18. Sealant web 32 is made of PVDC
As coated onto coated nylon film 31, sealant web 32 contacts the PVDC coating. The PVDC coated nylon film and sealant web 32 are sandwiched together by applying the nip roll 19 to the lamination roll 18. The laminate can then be passed around further heated lamination rolls 18 or into a hot zone to strengthen the bond between the sealant web and the PVDC coating. The laminate 33 so formed is wound into a roll, not shown.

In some embodiments of the invention, a single PVDC coating can be used that functions as both layers of PVDC. The crystallinity specifications for a single PVDC must meet the specifications for two PVDC layers. A single PVDC can be applied in two steps or in one step, as described below. A one-step process is particularly useful in the case of oriented nylon, polyester or polypropylene films, whereas a two-step process may be desirable for cast nylon films. This is because this film tends to curl in the presence of moisture.

In a one-step method of lay down with a single application of PVDC coating, only one
One coating station and associated dryer would be used. Additionally, for structures with intervening layers of crystalline PVDC, a third coating station and associated dryer (none of which are shown) would be required.

When handling cast nylon films, ie, nylon films that are not substantially oriented, it may be necessary to apply lateral tension to the film to prevent it from curling as it passes through the dryer. This is particularly desirable in dryers that apply heat to only one side of the film, such as the Faustel™ dryer.

When handling base films of oriented nylon, oriented polyester or oriented polypropylene,
It may be desirable to pass the coated film through the dryer under very low longitudinal tension. So-called floater dryers are suitable. This kind of dryer is
Prevents pulling of the film under tension, which would otherwise induce wrinkles in the film.

When the base film is a sealant web, it is necessary that the coefficient of the film be less than about 0.4, preferably less than about 0.3, and especially less than about 0.2. Sealant webs having a slip coefficient of less than about 0.2 are sometimes referred to by those skilled in the art as "high slip" films.

The base film also has a metal coating to render the final film structure substantially impermeable to oxygen. Metals, such as aluminum, can be applied by known methods, for example by vacuum evaporation. The amount of metal deposited onto the base film depends on the desired oxygen permeability of the final film structure. Typically,
Aluminum is heated until the optical density is approximately 2.5.
Deposited. The optical density is the logarithm of the quotient of the intensity of a ray of wavelength 500 nm before passing through the film structure as the dividend and the intensity of the ray after passing through the film structure as the divisor. Optical density can be measured using a Cary™ 210 UV-visible spectrophotometer. Since aluminum-coated base films are typically coated with a PVDC coating adjacent to the aluminum, the functional integrity of the aluminum coating remains when the structure is used in packaging operations, e.g.
Will not be damaged by pinholes or scratches, as may be present on the outside of the package.

It is often desirable to apply colored designs and/or printing onto a base film-PVDC coating-sealant web structure. In the context of the present invention, such designs and/or printing can be placed on the structure using ink applied to the base film or sealant web. Thus, the printing will exist between the base film and the PVDC coating or between the PVDC coating and the sealant web. Corona discharge treatment of the surface to be printed may be desirable; the extent of ink adhesion depends in part on the bond strength between the ink and the base film or between the ink and the PVDC coating. Select an ink that bonds well to the PVDC coating and to the base film,
Ensure that the bond strength of adjacent layers in the final structure is sufficient for the anticipated end use.

If PVDC coated base film is available in place of uncoated film, PVDC
The coated base film may need to be heated to substantially destroy the crystallinity in the PVDC.
For example, pre-coated base film
The PVDC coating is dry and at 20°C.
PVDC has a crystallinity of less than 1.15 when left standing for 30 days, and a crystallinity of 1.12 to 1.25 when dried and left standing at 40°C for 5 days.
The coated base film can be heat laminated directly by passing it through a nippro roll assembly, provided that the temperature of the lamination roll 18 is sufficiently high, e.g.
℃ to substantially destroy the crystallinity developed in the PVDC coating. The PVDC coated base film should be heated sufficiently to reduce or maintain a crystallinity of less than 1.05. Available in rolls,
Such PVDC coated base films may have a slip sheet between the layers of film on a roll or may contain an anti-blocking agent such as wax or talc.

In addition, pre-coated with PVDC coating,
The base film is coated with PVDC onto the sealant web in a second coating station, the PVDC having a crystallinity of less than 1.15 when dried and left for 30 days at 20°C, and subsequently dried and heated as described above. By laminating, heat lamination can be performed.

In this specification, when referring to PVDC precoated films, the calculation of the number of days on which the crystallinity of the PVDC was determined is applied.
Starting immediately after the PVDC dispersion has dried,
You should understand that. If the film is coated by someone (the coater) other than the person doing the laminating (the laminator), the age of the film since it was coated and the storage temperature of the film may not be apparent to the laminator. Therefore, laminators will need to inquire regarding the properties of the PVDC used as the base film coating.

In cases where the base film is a cast nylon film or a sealant web, the lamination temperature should be kept as low as possible to minimize shrinkage and other effects associated with heating the nylon film to too high a temperature. In these cases, lower heat sealing temperatures are advantageous for the subsequent PVDC coating on the sealant web. Generally, such PVDC coatings are dried and cooled at 20°C.
It has a crystallinity of less than 1.05 when left standing for 30 days. Three types of PVDC suitable for this purpose
The dispersion liquid is Serfene2011, Serfene2012,
Serfene2015.

Comes into contact with the sealant web when it is not PVDC coated
It is believed to be important that the crystallinity of the PVDC coating is less than 1.05 immediately before lamination. The temperature of the PVDC coated base film is approximately 75°C when it leaves the second dryer.
It should be lower to keep the PVDC coating sufficiently dry and the so-called "green tack" of the dry PVDC coating. Approximately 75℃
At higher temperatures, the "green tack" or adhesion of dried PVDC coatings may be insufficient. The temperature of the lamination roll is at least about 70°C, preferably at least
At 85°C, the PVDC coating should remain substantially amorphous or convert to amorphous. More particularly, the temperature of the lamination roll should be at least about 95°C. The temperature of the lamination roll should be below the melting point of the sealant web, preferably at least about 20°C below the melting point of the sealant web. Without wishing to be bound by any theory, it is believed that the selection of the temperature at which the lamination roll is operated depends, in part, on the softening point of the sealant web.

As indicated above, the sealant web can contain slip additives.

The types of PVDC coatings useful for coating base films and/or laminating sealant webs generally have a 15.6 ml/m ² /
It has an oxygen permeability of about atm/day. This is believed to be sufficient for most applications. If a lower oxygen permeability is required, a highly crystalline PVDC coating within the scope of the PVDC coatings of the present invention could be selected. Alternatively, both sides of the base film can be coated with PVDC. As a further alternative, crystalline PVDC
Coatings, such as those having a dry crystallinity greater than about 1.30, can be sandwiched between the first and second PVDC coatings used in the present invention. As previously mentioned, an aluminum coating can be placed between the base film and the PVDC coating. Using vacuum evaporated aluminum,
Oxygen permeability of about 0.75ml/m ² /atmosphere/day can be obtained.

Nylon copolymers, such as nylon 6/
66 is preferred for applications requiring package pinhole resistance. A preferred laminate for cheese packaging consists of a nylon-based film and a sealant web of film made from a blend of a linear copolymer of ethylene and _C4 - _C8 alpha-olefins and a copolymer of ethylene and vinyl acetate. .

As can be seen, one method consists of coating the film with two coatings of PVDC and then heat laminating the PVDC coated film to the sealant web. No.
1PVDC coatings are applied under conditions that minimize the chance of curling or wrinkling caused by high temperatures and/or the presence of excessive amounts of moisture. This is primarily due to the use of as little PVDC as possible.
Applying the dispersion to a nylon film, PVDC
The coverage of the nylon film by the nylon film is achieved so that, after drying, there is little chance of water uptake by the nylon film during the second application of the PVDC dispersion. For these reasons, the first layer of the PVDC dispersion is typically about 2.44 to 3.25
g/m ² (dry basis). Additionally, it is desirable to control the lateral tension of the film as it passes through the dryer. The amount of tension required will vary according to the type of nylon film, the amount of PVDC emulsion applied, the temperature of the dryer and the type of dryer, eg, one side or two side direction of the heat towards the film. Typically 4-7N/
The level of tension across the film width m is preferred.

The second coating of PVDC is 2.44~6.51g/ ^m2
(dry standard) is applied, but 2.44 to 3.25
g/m ² will be sufficient to provide the required moisture and oxygen permeability levels to the final film laminate structure.

The thinner the cast nylon film, the lower the application speed of the first coating of PVDC to the lowest possible level, e.g.
It is more important to maintain 2.85 g/m ² and control the lateral tension of the coated film as it passes through the dryer.

However, the preferred method is to coat the sealant web with PVDC, thus completely overcoming the moisture sensitivity problem of nylon.
In addition to this advantage, there is the further advantage of being able to choose a single coating of PVDC.

Since cast nylon films are sensitive to wrinkling at high temperatures, the temperature of the laminating roll should be as low as possible, and/or
Alternatively, the time that the nylon film is in contact with the laminating roll should be kept to the minimum necessary to achieve the desired bond of the laminate.

Oriented base films useful in the present invention include:
Not as sensitive to temperature and moisture as cast nylon films. Therefore, PVDC coatings can be applied as two separate layers or as a single layer. Higher dryer and lamination temperatures can be used and there is no need to apply lateral tension to the film as it passes through the dryer. In oriented base film,
A single application of PVDC dispersion is preferred.

When using the method of coating a sealant web with PVDC, it is essential that the surface of the sealant web to be coated with PVDC has a surface tension of at least 38 dynes/cm. Treatment of the surface with ozone or other oxidizing chemicals or corona discharge, as known in the art, is necessary to bring the surface tension to the required minimum level. Corona discharge treatment is preferred.

When coating and laminating equipment are not owned by the same manufacturer or, for reasons of adaptability, it is inconvenient to combine the coating and laminating equipment in an in-line manner, the so-called out-of-line coating and laminating - Can be achieved in two steps in a line process. In such methods, a base film or sealant web is coated with one or more PVDC coatings and wound into rolls. PVDC when unwinding
To prevent blocking of the coated film, a slip sheet can be used or the final PVDC coating can be formulated to include a slip or antiblock agent. The wound roll can then be stored for lamination to a sealant web or base film, as appropriate.
The PVDC coated film can then be heat laminated to other films in accordance with the present invention at a suitable time.

In order to ensure adhesion of the PVDC coating to the sealant web, in the process of laminating an uncoated sealant web to a PVDC coated base film, the PVDC coating must have a crystallinity of approximately 1.05 or less upon lamination. I believe that it is. this is
This can be achieved by heating the PVDC coated film just before or during lamination. The following Example 7 illustrates an out-of-line method.

The present invention will be explained by the following examples. Example 1 is typical of the prior art.

In embodiments, the melt index is
Measured according to ASTM D-1238 (Condition E).

Example 1 A 15 μm thick film of an oriented nylon copolymer (a copolymer of 10 wt% ε-carprolactam and 90 wt% hexamethylene diamine adipate) was prepared from a Serfene 2011 PVDC dispersion with 5 wt% isopropyl alcohol. 6.175g/
gravure coated directly at 30.3 m/ ^min . Serfene2011 PVDC had a crystallinity of 1.05 when dried and stored at 20°C for 30 days and 1.15 when stored at 40°C for 5 days. The coating was applied in a roll-supported arch dryer at 70°C as measured with a non-contact infrared pyrometer.
It was dried at a temperature of . The PVDC coated film was passed over a hot roll at a residence time of 0.33 seconds above a laminating roll held at 115°C. A 51 μm sealant web was laminated to a PVDC coated nylon film as described herein. The sealant web contains 85% by weight linear ethylene/butene.
1 copolymer, density of 0.919 g/ ^cm3 and
has a melt index of 0.75 dg/min, and 15
% by weight of high-pressure polypropylene, i.e. a homopolymer of ethylene, with a density of 0.920 g/cm ³ and
a blend with 75 ppm by weight and a blend with erucamide (slip additive), with a melt index of 0.8 dg/min.
The sealant web is 38 dynes/cm
It had been corona discharge treated to a surface tension level of .

The resulting laminate was stored at 20°C for 5 days. The bond strength of the laminate was then measured by a Suter tester and was 11-20 g/
It turned out to be cm.

Other sealant webs containing high pressure polyethylene with a melt index of 2-10 dg/min gave similar results.

Example 2 Example 1 is repeated, but the sealant web is
85% by weight linear ethylene/butene-1 copolymer, 15 parts by weight high pressure polypropylene with a density of 0.919 g/cm ³ and a melt index of 0.75 dg/min, a density of 0.920 g/cm ³ and 0.8 dg/min and a copolymer of ethylene/vinyl acetate of 15 parts by weight, with a vinyl acetate content of 12% by weight of the copolymer and a melt index of 0.35 dg/min, trademark Elvax3135X
Available in a blend of The sealant web had a slip coefficient of approximately 0.2.

The bond strength of this laminate is 5 at 20°C.
After storage for a day, it was tested and found to be 630 g/cm.

Example 3 Repeat Example 2 but with 1 PVDC of Serfene201
A PVDC dispersion of Serfene2060 was used instead of the dispersion. The PVDC dispersion of Serfene2060 has a 1.10,
and had a crystallinity of 1.19 when stored for 5 days at 40°C.

The bond strength of this laminate is 5 at 20°C.
After storage for a day, it was tested and found to be 630 g/cm.

Example 4 Example 3 is repeated, but instead of the oriented nylon film 10% by weight of ε-caprolactam and
A 25 μm thick cast film made from a 90% by weight hexamethylene diamine adipate copolymer was used.

The bond strength of this laminate is 5 at 20°C.
After being stored for a day, it was tested and found to be 630 g/cm. However, the laminate curls severely in both machine and transverse directions;
The amount of moisture displaced in the dryer, and possibly the temperature of the thermal laminating rolls, indicated that the temperature was too high for cast film lamination.

Example 5 The cast film of Example 4 was coated with 3.25 g/m ²
It was coated with a PVDC dispersion of Serfene2060 and dried. This cast film was then wound together with a slip sheet of high density polyethylene film. After several hours, the cast nylon film was coated with 3.25 g/m ² of Serfene 2015 PVDC dispersion and wound onto a secondary winder.
Serfene2015 PVDC had a crystallinity of 1.00 when dried and stored at 20°C for 30 days, and 1.15 when stored at 40°C for 5 days.
The Serfene 2015 PVDC coating was dried in a roll-supported arch dryer at a temperature of 70°C as measured with a non-contact infrared pyrometer. The PVDC coated film was passed over a hot roll with a residence time of 0.33 seconds above a laminating roll held at 90°C. The sealant web is as described in Example 2.
Laminated to PVDC coated nylon film. The resulting laminate was substantially curl-free and had a bond strength of at least 500 g/cm when tested after storage for 5 days at 20°C.

Example 6 An 11 μm thick film of oriented nylon copolymer (a copolymer of 10 wt% ε-caprolactam and 90 wt% hexamethylene diamine adipate) was mixed with 7.8 g of Serfene 2011 PVDC dispersion with 5 wt% isopropyl alcohol. / ^m2
Then, I directly gravure coated it. The cast film was dried in a roll-supported arch dryer at a temperature of 70°C as measured with a non-contact infrared pyrometer. The coated film was passed over a hot roll at a dwell time of 0.33 seconds over a laminating roll held at 115°C and laminated to the sealant web. The sealant web was made of 50 parts by weight of ethylene/vinyl acetate copolymer, a density of 0.940 g/cm ³ and 1.2 dg/cm 3 .
With a melt index of 18% and a vinyl acetate content of 18% by weight of the copolymer, trademark
42.5 parts by weight linear ethylene/butene-1 copolymer, available as Ultrathene UE-632, 0.919
a blend of 7.5 parts by weight of high ^{pressure polypropylene, having a density of 0.920 g/cm 3 and} a melt index of 0.8 dg/min, 75 ppm by weight and a blend with erucamide (slip additive).

The resulting laminate was stored at 20°C for 5 days. The bond strength of the laminate was then tested and found to be at least 630 g/cm.

Example 7 A 15 μm thick oriented nylon 66 film was
parts by weight of Serfene 2060 PVDC dispersion, 2 parts by weight of
DL-96(TM) wax emulsion and 0.3
It was coated with 4.06 g/m ² of a mixture of parts by weight of OX-50™ silicon dioxide antiblock agent. Dry the cast film, roll it up, and leave it at room temperature for 6 days.
Stored for a month. Then the PVDC coating is
It was found to have a crystallinity of 1.31±0.02.

The cast film was then passed through a roll-supported arch dryer at 30.5 m/min with a residence time of 2.5 seconds. The temperature of the dryer was 110°C. The cast film was then passed over a laminating roll maintained at 115°C.
The sealant web of Example 6 was laminated to a PVDC coated nylon film.

The bond strength of the resulting laminate was at least 500 g/cm after storage for 5 days at 20°C.

Example 8 Example 2 is repeated, but the sealant web is
It was made from a copolymer of ethylene and vinyl acetate, available from C-I-L Inc. under the trademark 1060, having a melt index of 1.5 and a vinyl acetate content of 6% by weight.

The bond strength of the resulting laminate was at least 630 g/cm after storage for 5 days at 20°C.

Example 9 4.06% of Serfene 2060 PVDC dispersion containing 5% by weight isopropyl alcohol as in Example 1 with a 15 μm thick oriented nylon film
g/m ² and dried to a temperature of 70°C, then maintained at 115°C and passed at a speed of 30-35 m/min. The residence time on the laminating roll was 0.33 seconds. The PVDC coated nylon film was laminated to an 18 μm thick biaxially oriented polypropylene film that was acrylic-coated on both sides. The resulting laminate was coated on the uncoated side of the nylon film with 4.06 g/m ² of Serfene 2060 PVDC dispersion containing 5% by weight isopropyl alcohol. The latter PVDC coating was laminated to the sealant web of Example 6.

The bond strength was measured after the laminate was stored at 20° C. for 5 days. The bond strength was about 150 g/cm between the coated oriented polypropylene film and the nylon film, and at least 630 g/cm between the EVA-containing film and the nylon film.

Example 10 15μm with Serfene2060PVDC coating
A nylon copolymer film having a thickness of 100 mL was prepared substantially as described in Example 1 and laminated with a regenerated cellulose film coated on one side with nitrocellulose. The resulting laminate was coated on a second side of nylon and laminated to an EVA-containing film as described in Example 9.

The bond strength between nylon film and cellulose film was 78 after storage at 20℃ for 5 days.
g/cm.

Example 11 A 15 μm thick film of oriented copolymer nylon was coated with Daran™ 820 PVDC dispersion at 6.99 μm.
Coated at g/m ² . The obtained coated film was dried and heated to 115°C as described in Example 6.
It was laminated to an EVA-containing film.

The bond strength was found to be 350 g/cm after storage for 5 days at 20°C.

Example 12 51 μm thick cast nylon 6 film containing 5% by weight of isopropyl alcohol
Coated with 6.99g/ ^m2 of Serfene2060 dispersion, 120
It was passed through a dryer maintained at 0.degree. C. with a residence time of 4 seconds. The coated film leaving the dryer had a temperature of 74°C. The obtained film is
The sealant web of Example 6 was laminated.

The bond strength was found to be 275 g/cm after storage for 5 days at 20°C. The film curled slightly, but the Multivac(TM) 8000
It was effectively used in thermoforming using a vacuum thermoforming machine.

Example 13 Cast nylon 66 film 76 μm thick containing 5% by weight isopropyl alcohol
It was coated with 3.49 g/m ² of Serfene 2060 dispersion.
The coated film leaving the dryer had a surface temperature of 72°C. The obtained film is 125μm
laminated to a sealant web of thickness. The sealant web comprises 85 parts by weight of ethylene/butene-1 copolymer, a density of 0.919 g/ ^cm3 and
having a melt index of 0.75 dg/min and made from a blend of 15 parts by weight of an ethylene/vinyl acetate copolymer, having a vinyl acetate content of 12% by weight of the copolymer and a melt index of 0.35 dg/min. . The PVDC coated film was passed through a laminating roll held at 112°C with a dwell time of 0.7 seconds on the hot roll, 60% of which time was in contact with the sealant web.

The bond strength of the laminate was found to be 560 g/cm after storage at 20° C. for 5 days. The laminate was flat and thermoformable.

Example 14 An oriented polyester film, i.e. a polyethylene terephthalate film, with a thickness of 11 μm,
Corona discharge treated to a surface tension level of 40 dynes/cm, was coated with 4.88 g/m ² of Serfene 2060 dispersion containing 5% by weight isopropyl alcohol. The coated film was passed through a dryer maintained at 138°C. The surface temperature of the coated film leaving the dryer was 70°C.
The film was passed through a laminating roll maintained at 113°C with a residence time of 0.3 seconds. The coated film was laminated to the sealant web of Example 13.

The bond strength of the laminate was found to be at least 630 g/cm after storage for 5 days at 20°C.

Example 15 85 parts by weight of a linear ethylene/butene-1 copolymer, with a density of 0.919 g/cm ³ and a melt index of 0.75 dg/min, and 15 parts by weight of an ethylene/vinyl acetate copolymer, 18% by weight A sealant web made from a blend of , having a vinyl acetate content of , and a melt index of 0.7 dg/min, was corona discharge treated to a surface tension level of about 42 dynes/cm. This sealant web
It had a slip coefficient greater than 0.5. The sealant web was coated with 4.3 g/m ² of Serfene 2015 PVDC dispersion containing 10% by weight isopropyl alcohol. Let the coating dry and then 25μ
m thick nylon 66 film, while the nylon film was in contact with a hot roll heated to 92°C.

The resulting laminate has a bond strength of at least 600 g/cm ³ , measured after storage for 5 days at 20°C;
and had an oxygen permeability measurement of less than 0.8 ml/m ² /day/atmosphere.

Example 16 The sealant web of Example 2 was heated to about 42 dynes/
corona discharge treatment to the level of cm, then 4.8g/
m ³ of Serfene 2011 PVDC dispersion, dried and wound together with a slip sheet onto a roll. Subsequently, the PVDC coated sealant web was unwound to 4.8 g/m
Coated with Serfene2015PVDC dispersion, dried,
It was then nipped against a base film that was the same as the sealant web. The base film is
It was placed in contact with a hot roll heated to 8.2°C.

The resulting laminate has a bond strength of at least 600 g/cm ³ , measured after storage for 5 days at 20°C;
and a low oxygen permeability measurement of 7.8 ml/m ² /day/atmosphere.

[Brief explanation of the drawing]

FIG. 1 shows the method of the invention in diagrammatic form. 10...first coating station, 11
...First dryer, 12...Second coating station, 13...Second dryer, 14...
...Nitspro roll assembly, 16...Gravure roll, 17...Gravure roll, 18...Lamination roll, 19...Nitspro roll, 20
...Nitsprol, 21...Nitsprol, 30
... Nylon film, 31 ... PVDC-coated nylon film, 32 ... Sealant web, 33 ... Laminate, 34 ... Bread, 35 ...
...Bread, 36...Lay on roll, 37...Ley on roll, 38...Take off roll.

Claims (1)

Claims: 1. A film laminate comprising a base film, a first sealant web, and a sandwiched PVDC coating therebetween, the first sealant web comprising: (a) ethylene and vinyl acetate; and (b) (1) a copolymer of ethylene and vinyl acetate and (2)
Homopolymer of ethylene or ethylene and 1
copolymers with one or more C ₄ to C ₁₀ α-olefins, provided that the homopolymers or copolymers have a density of from about 0.915 to about 0.955 g/cm ³ , or blends of said homopolymers and copolymers; the base film is selected from the group consisting of an oriented nylon film, an oriented polyester film, an oriented polypropylene film, and a second sealant web, and the second sealant web is selected from the group consisting of a blend of the selected from the same group as the first sealant web and having a slip coefficient of less than about 0.4, said PVDC coating comprising at least one layer, which layer is less than 1.15 when dry and left undisturbed for 30 days at 20°C. By having crystallinity and when the base film is chosen from nylon film, polyester film or polypropylene film, the layer in contact with this base film has a crystallinity of 1.12 to A film laminate characterized by having a crystallinity of 1.25. 2 a film laminate comprising a base film and a first sealant web and a sandwiched PVDC coating therebetween, provided that the first sealant web is (a) a film made from a copolymer of ethylene and vinyl acetate; , and (b) (1) a copolymer of ethylene and vinyl acetate; and (2)
Homopolymer of ethylene or ethylene and 1
copolymers with one or more C ₄ to C ₁₀ α-olefins, provided that the homopolymers or copolymers have a density of from about 0.915 to about 0.955 g/cm ³ , or blends of said homopolymers and copolymers; the base film is selected from the group consisting of an oriented nylon film, an oriented polyester film, an oriented polypropylene film, and a second sealant web, and the second sealant web is selected from the group consisting of a blend of the a first sealant web selected from the group consisting of a PVDC coating having a slip coefficient of less than about 0.4; By having crystallinity and when the base film is chosen from nylon film, polyester film or polypropylene film, the layer in contact with this base film has a crystallinity of 1.12 to characterized by having a crystallinity of 1.25, wherein a base film and a first sealant web are fed together between a nip roll and a hot roll, wherein the PVDC coating covers at least the base film. or applied to a first sealant web, provided that when the first sealant web or the second sealant web is in contact with a hot roll, said web in contact with the hot roll has a slip coefficient of less than about 0.4. A method characterized by: 3 (a) heating the PVDC coated base film or first sealant web to a degree sufficient to reduce the crystallinity of the PVDC coating to less than about 1.05; (c) when a PVDC coated base film is used, the first sealant web is brought into contact with the PVDC coating, and between the nip roll and the hot roll, the first sealant web is passed over the hot roll; PVDC
The base film is sandwiched against a coated base film to form a laminate, and when a PVDC coated base film is used, the base film is brought into contact with a PVDC coated first sealant web between a nip roll and a hot roll to form a laminate. 3. The method of claim 2, comprising: forming. 4 (a) PVDC coated base film,
heating the PVDC coating to a degree sufficient to reduce the crystallinity of the coating to less than about 1.05, such that the PVDC has a crystallinity of less than 1.15 when dried and left at 20° C. for 30 days; When the base film is selected from nylon film, polyester film or polypropylene film, the PVDC coating is dried and
(b) The PVDC coated base film is further characterized by having a crystallinity of 1.12 to 1.25 when left standing for 5 days at °C.
coating with a PVDC dispersion to form a second PVDC coating, wherein the second PVDC coating is characterized by having a crystallinity of less than 1.15 when dried and left at 20° C. for 30 days; (c) dry and subsequently apply a second PVDC coating until the temperature of the free surface of said second coating is
(d) passing the resulting PVDC coated base film over a heated roll, said base film being in contact with said heated roll, said heated roll having a temperature of about 75°C; and (e) contacting the first sealant web with a second PVDC coating and between a nip roll and a hot roll, the first sealant web is coated with PVDC.
3. The method of claim 2, comprising sandwiching the laminate to a coated base film. 5 (a) PVDC coated base film,
heating the PVDC coating to a degree sufficient to reduce the crystallinity of the coating to less than about 1.05, such that the PVDC has a crystallinity of less than 1.15 when dried and left at 20° C. for 30 days; When the base film is selected from nylon film, polyester film or polypropylene film, the PVDC coating is dried and
(b) a first sealant web having a surface tension of at least 42 dynes/cm with an aqueous PVDC dispersion; coating to form a PVDC coated first sealant web, wherein the PVDC coating on the sealant web is dried and
(c) drying the PVDC coating on the first sealant web; and (d) rolling the PVDC coated base film. the base film is in contact with the hot roll, and the hot roll is about 70 m
and (e) the temperature of the PVDC coated first sealant web.
contacting a PVDC surface with a PVDC surface of a PVDC coated base film and sandwiching the PVDC coated sealant web against the PVDC coated base film between a nip roll and a hot roll to form a laminate. The method according to claim 2, which comprises: 6 (a) Coating the PVDC-coated first sealant web with an aqueous PVDC dispersion
2PVDC coating is formed, and at this time the above-mentioned
2PVDC coatings are characterized by having a crystallinity of less than 1.15 when dry and left standing at 20°C for 30 days, and when the base film is chosen from nylon film, polyester film or polypropylene film. 2PVDC coating is
When dried and left at 40℃ for 5 days,
further characterized by having a crystallinity of 1.12 to 1.25, and said PVDC coating adjacent the first sealant web having a crystallinity of less than 1.15 when dried and left for 30 days at 20°C. (b) drying the second PVDC coating; (c) passing a base film over a hot roll, said base film being in contact with said hot roll; and said base film being in contact with said hot roll. and (d) contacting the base film with a second PVDC coating and sandwiching the base film against the PVDC coated first sealant web between a nip roll and a hot roll. 3. The method of claim 2, comprising: forming. 7 (a) Coating a base film with an aqueous PVDC dispersion, the resulting coating being characterized by having a crystallinity of less than 1.15 when dried and left at 20° C. for 30 days. , and when the base film is selected from nylon film, polyester film or polypropylene film,
The PVDC coating is further characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40°C for 5 days, (b) drying the PVDC coating, (c) PVDC coated base. (d) passing a film over a hot roll, the base film being in contact with the hot roll, and the hot roll being at a temperature greater than about 70°C; and (d) passing a PVDC coated first sealant web.
The PVDC coated surface is brought into contact with the PVDC coated surface of the PVDC coated base film, and between the nip roll and the hot roll,
3. The method of claim 2, comprising sandwiching a PVDC coated sealant web to a PVDC coated base film to form a laminate. 8 (a) Coating the base film with a first PVDC, the coating being dried and
characterized by having a crystallinity of less than 1.15 when left undisturbed for 30 days at °C;
and when the base film is selected from nylon film, polyester film or polypropylene film, the PVDC coating is further characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40°C for 5 days; (b) coating the PVDC coated base film formed in step (a) with a second PVDC to form a second PVDC coating, wherein the second coating is dried and heated at 20°C;
characterized by having a crystallinity of less than 1.15 when left undisturbed for 30 days; (c) heating said second coating, wherein the temperature of the free surface of said second coating is less than 75°C; (d) passing the resulting PVDC coated base film over a hot roll, said base film being in contact with said hot roll, and said hot roll being at a temperature greater than about 70°C, and ( e) contacting a sealant web with a second PVDC coating and sandwiching the sealant web against a PVDC coated base film between a nip roll and a hot roll to form a laminate. The method described in Scope No. 2. 9 (a) coating a first sealant web with a first PVDC having a surface tension of at least 38 dynes/cm to form a first PVDC coating, wherein the coating, when dry and allowed to stand at 20°C for 30 days; (b) coating the PVDC-coated first sealant web formed in step (b) with a second PVDC, wherein the second coating is dried and It is characterized by having a crystallinity of less than 1.15 when left at 20°C for 30 days, and the base film is a nylon film,
When selected from polyester films or polypropylene films, the PVDC coating is further characterized by having a crystallinity of 1.12 to 1.25 when dried and left at 40°C for 5 days; (c) the base film is (d) the base film formed in steps (a) and (d) is passed over a hot roll, the base film being in contact with the hot roll, and the hot roll being at a temperature greater than about 70°C; contacting the PVDC-coated surface of the PVDC-coated first sealant web with a base film, and sandwiching the PVDC-coated first sealant web against the base film between a nip roll and a hot roll to form a laminate. The method according to claim 2, which comprises: 10 The first sealant web comprises: (a) a copolymer of ethylene and vinyl acetate, and (b) a copolymer of ethylene and vinyl acetate, and (1) a copolymer of ethylene and a _C4 to _C10 alpha-olefin, provided that Copolymer is about 0.915 to about 0.955
and ( ² ) a homopolymer of ethylene, having a density of about 0.915 to about
of a material selected from the group consisting of a blend with at least one of, having a density of 0.955 g/ ^cm3 ;
having a surface adjacent to a PVDC coating;
A method according to any one of claims 2 to 9. 11 The vinyl acetate content of the ethylene and vinyl acetate copolymer is from about 1.0 to about 20% by weight and the weight ratio of the ethylene and vinyl acetate copolymer to the ethylene homopolymer, ethylene copolymer, or blends thereof is 2:98. 10. A method according to any of claims 2 to 9, wherein the ratio is 50:50. 12. The method according to any one of claims 2 to 9, wherein the base film is a nylon film. 13. The method of any of claims 2-9, wherein the base film is a sealant web having a slip coefficient of less than about 0.3. 14. Claims 2-9, wherein the heat roll is at a temperature in the range of about 85°C to the melting point of the sealant web.
The method described in any of the paragraphs.