EP0859811A1

EP0859811A1 - Vinylidene chloride polymer compositions and irradiated articles prepared therefrom

Info

Publication number: EP0859811A1
Application number: EP96941964A
Authority: EP
Inventors: Douglas E. Beyer; Martin F. Debney; Levi Kishbaugh
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1995-11-09
Filing date: 1996-11-05
Publication date: 1998-08-26
Also published as: JP2000500511A; KR19990067401A; CN1202189A; AU1116697A; WO1997017399A1; CA2236147A1

Abstract

A composition comprising a mixture of (1) a vinylidene chloride polymer formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one ethylenically unsaturated monomer copolymerizable therewith and (2) an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the vinylidene chloride polymer during and after irradiation of the composition is used to prepare a heat-shrinkable multilayer film. The composition may also contain an amount of a color stable violet or blue dye sufficient to mask color bodies formed during and after irradiation of the composition.

Description

VINYLIDENE CHLORIDE POLYMER COMPOSITIONS AND IRRADIATED ARTICLES PREPARED THEREFROM

This invention relates to vinylidene chloride polymer (PVDC) compositions and films comprising said compositions. More particularly, this invention relates to vinylidene chloride compositions having improved resistance to color degradation induced by irradiation.

Irradiation of PVDC films often improves film properties such as puncture resistance, tensile strength and toughness. However, under most circumstances, irradiation results in substantial discoloration, such as yellowing, of the films.

Attempts have been made in the past to stabilize PVDC films against color degradation by adding epoxidized soybean oil (ESO) or epoxidized linseed oil (ELO) to vinylidene chloride copolymer compositions. See, for example, U.S. Patent 4,714,638 and Canadian Patent 982823. However, although films containing ESO or ELO plasticizer had Iower initial color (color of the film coming out of the extruder) compared to control films (no ESO or ELO plasticizer), the color of such films increased substantially after irradiation, while that of the control films did not.

It would be desirable to provide additives which effectively minimize color degradation of PVDC films during and after irradiation.

In a first aspect, this invention is a composition comprising a mixture of (1) a vinylidene chloride polymer (PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and (2) an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC during and after irradiation of the composition.

In a second aspect, this invention is a composition comprising a mixture of (1) a vinylidene chloride polymer (PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC, and an amount of a color stable violet or blue dye sufficient to mask color bodies formed, during and after irradiation of the composition.

In a third aspect, this invention is a heat-shrinkable multilayer film comprising a layer of a vinylidene chloride polymer formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and containing an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC, and or an amount of a color stable violet or blue dye sufficient to mask color bodies formed, during and after irradiation of the composition.

The aliphatic ester compounds have been found to minimize color degradation in PVDC films during and after irradiation of the PVDC films while imparting the desirable effects as a processing aid during film extrusion.

Vinylidene chloride polymers suitable for use in the present invention are well-known in the art. See, for example, U.S. Patents 3,642,743; and 3,879,359 As used herein, the term "vinylidene chloride polymer" encompasses homopolymers of vinylidene chloride, and also copolymers, teφolymers. thereof, wherein the major component is vinylidene chloride and the remainder is one or more ethylenically unsaturated monomer copolymerizable with the vinylidene chloride monomer.

Monoethylenically unsaturated monomers suitable for use in the present invention are those which can be polymerized with the vinylidene chloride monomers, to form the vinylidene chloride polymers. Examples of monoethylenically unsaturated monomers include alkyl acrylates, alkyl methacrylates, acrylic acid, methacrylic acid, itaconic acid, vinyl chloride, acrylonitrile and methacrylonitrile. The monoethylenically unsaturated monomers are desirably selected from alkyl acrylates and alkyl methacrylates having from 1 to 8 carbon atoms per alkyl group. The alkyl acrylates and alkyi methacrylates preferably have from 1 to 4 carbon atoms per alkyl group. The alkyl acrylates and alkyl methacrylates are most preferably selected from methylacrylates, ethylacrylates, and methyl methacrylates.

Most preferred vinylidene chloride polymers include polymers formed from 91 to 96 weight percent vinylidene chloride and from 4 to 9 weight percent of methyl acrylate.

The vinylidene chloride polymers are generally formed through an emulsion or suspension polymerization process. Exemplary of such processes are described in U.S. Patents 2,558,728; 3,007,903; 3,642,743; and 3,879,359; and the methods described by R. A. Wessling, in Polyvinylidene Chloride. Gordon and Breach Science Publishers, New York, 1977, Chapter 3. Typically, the monomeric materials are emulsified or suspended in an aqueous phase. The aqueous phase contains a surface active agent capable of emulsifying or suspending the monomeric materials in the aqueous phase. The polymerization of the monomeric materials is usually carried out with heating and agitation in the presence of a polymerization initiator. After polymerization is complete, the resultant polymeric material is vacuum stripped. Thereafter, the slurry is cooled down, unloaded and dewatered, and the resin is collected and further dried.

The aliphatic ester compounds suitable for use in the present invention for minimizing color degradation in irradiated PVDC films include linear and branched aliphatic ester compounds, polymeric aliphatic esters and mixtures thereof, which are essentially free of epoxy or aromatic functionality and have a molecular weight of from 300 to 8000. Preferred aliphatic ester compounds include acetyl tributyl citrate, acetylated monoglycerides, diesters of adipic, azelaic, sebacic and glutaric acids; polyesters of glycerol and pentaerythritol and polymeric adipates, azelates, sebacates and glutarates. More preferred aliphatic ester compounds are acetyl tributyl citrate, acetylated monoglycerides, dibutyl sebacate and polymeric adipates. The most preferred aliphatic ester compounds are acetylated monoglycerides. These aliphatic ester compounds are well known in the art and are commercially available.

While the amount of aliphatic ester compound most advantageously employed depends on a variety of factors, such as the specific monomers, in general, the aliphatic ester compound is used in an amount of from 0.2 to 15 weight percent, preferably from 0.5 to 10 weight percent and most preferably from 1 to 4 weight percent, based on the weight of the PVDC.

Violet or blue dyes suitable for use in the present invention are the organic dyestuffs which are sufficiently color stable to withstand the acidic processing environment of PVDC extrusion at about 160°C and include the 1-hydroxy-4-aryl-aminoanthraquinones which are color stable. The 1-hydroxy-4-aryl-aminoanthraquinones are known and are described, for example in U.S. Patent 2,419,405. The most preferred violet pigment is commercially known as C.l. Solvent Violet 13, available as Macrolex™ Violet B, a product of Bayer AG and represented by the formula:

The amount of violet or blue dye used must be sufficient to mask at least a portion of color bodies developed in the vinylidene chloride polymer composition during irradiation of the composition. Generally, the violet or blue dye can be present in an amount of from 0.0005 to 0.05 weight percent, preferably, from 0.0007 to 0.01 weight percent and most preferably, from 0.001 to 0.005 weight percent, based on the weight of the PVDC.

The vinylidene chloride polymer composition of the present invention may also contain various additives to impart desirable properties such as, for example, heat stabilizers, light stabilizers, processing aids, and lubricants, but substantially excluding the aromatic or epoxidized processing aids, such as dioctyl phthalate or epoxidized soybean oil, which may not be effective to minimize the color degradation (formation of color bodies) of the PVDC. Each of these additives is known and several types of each are commercially available.

The vinylidene chloride polymer composition of the present invention can be prepared by adding the aliphatic ester compound and/or violet or blue dye to the monomer mix before or during polymerization or to the dry vinylidene chloride polymer by dry blending. Preferably, the composition is prepared by adding the aliphatic ester compound and/or violet or blue dye to the monomer mix to ensure a more uniform distribution of the aliphatic ester compound and/or violet or blue dye in the resulting polymer.

The violet or blue dye can also be added in the form of a concentrate by melt blending the concentrate with the vinylidene chloride composition using typical melt processing equipment such as, for example, two-roll compounding mills, Brabender mixers, Banbury mixers, single screw extruders, twin screw extruders and the like. The concentrate can be prepared by mixing the violet or blue dye with a carrier resin which, preferably, is vinylidene chloride polymer. Methods for preparing the concentrate are well-known in the art. Typically, the carrier resin and the violet or blue dye are blended in the melt using conventional melt processing techniques, using typical melt processing equipment such as those mentioned previously.

If the composition is prepared by dry blending, the components should be mixed to form a visually uniform admixture. Suitable dry blending equipment includes tumble blenders, Hobart mixers, Welex mixers, and Henschel high intensity mixers.

The vinylidene chloride polymer composition of the present invention can be coextruded into a multilayer film with conventional coextrusion machines. Heat-shrinkable multilayer films employed in packaging meats, for example, can be produced by coextruding the multiple layers into a primary tube, and then biaxially stretching the tube by known techniques, such as that described in U.S. Patent 3,555,604, to form a heat-shrinkable film. The biaxially-stretched film is then irradiated to a dosage level of up to about 5 megarads by passing it, for example, through an electron beam irradiation unit or Co-60 gamma radiation source. The multilayer film can have one or more layers comprising the vinylidene chloride polymer composition of the present invention and one or more layers comprising a polyolefin, such as polyethylene. The vinylidene chloride polymer layer can be sandwiched between two or more layers of a polyolefin. The multilayer film can also have a glue layer disposed between a vinylidene chloride polymer layer and an adjacent polyolefin layer. The glue layer typically comprises ethylene vinyl acetate or any polymer or copolymer having good adhesive properties.

The PVDC compositions of the present invention can also be fabricated into articles using conventional fabrication techniques such as injection molding, extrusion molding, calendering, thermoforming, and lamination techniques. Articles formed therefrom include blown and cast monolayer and multilayer films, foam sheets, tubes, pipes, fibers and the like. Examples of such articles include flexible and rigid containers used for the preservation of food, drink, medicine and other perishables.

Fabricated articles from the present invention may be irradiated for purposes of sterilization, improving toughness, improving solvent resistance and the like. Irradiation with about 1 to 20 Mrad is accomplished, for example, by passing the articles through an electron beam irradiation unit or Co-60 irradiation source. Irradiation may be done during or after fabrication of the article.

The following working examples are given to illustrate the invention and should not be construed to limit its scope. Unless otherwise indicated, all parts and percentages are by weight.

EXAMPLES

In the following examples, color measurements are taken using the following procedure.

Color Measurement Color measurements were made using a Hunter Lab Ultra Lab Colorimeter. The operating conditions were llluminant D65, specular included, UV off, 10° observer, in a reflectance mode against a white tile. Measurements were made using the CIE Lab color scale. Four measurements were made of each sample and then averaged. Of greatest interest was the change in "b" value where increasing "b" corresponded to a visual increase in yellowness. The "Db" values reported were the difference in yellowness between the irradiated sample and the unirradiated control. A positive number corresponded to increased yellowness. It was observed that the polypropylene skin accounted for a "Db" of approximately 4 as a result of the irradiation. Therefore, the "Db" values reported for multilayer films in Table I are all decreased by 4 units. Example 1

A multilayer film sample (Sample 1) composed of outer layers of polypropylene and a core layer of 92.25 weight percent vinylidene chloride/7.75 weight percent methyl acrylate, which contained 4.0 weight percent dibutyl sebacate and 0.2 weight percent epoxidized soybean oil, was produced by conventional coextrusion technique. Prior to irradiation, the film was annealed at 120°F for 3 hours to ensure full crystallization of the vinylidene chloride copolymer. The coextruded film was irradiated with 4 Mrad Co-60 gamma radiation at ambient temperature. Color measurements were taken on the coextruded film prior to irradiation (unirradiated) and immediately after irradiation (irradiated) according to the color measurement procedure described previously. The results of this test, in terms of the change in yellow color (Db), is shown in Table I.

Examples 2 and 3

Two multilayer film samples (Samples 2 and 3) composed of outer layers of polypropylene and a core layer of 92.25 weight percent vinylidene chloride/ .75 weight percent methyl acrylate were prepared and tested (irradiated and color measurement taken) as in Example 1, except that 4 percent acetyl tributyl citrate (ATBC) is added in Sample 2 and 4 percent Eastman EPZ, an acetylated monoglyceride commercially available from Eastman Chemical, was added in Sample 3, instead of the 4 percent dibutyl sebacate. Color measurements of the irradiated films were taken as in Example 1 and the results are shown in Table I.

Comparative Example A

A multilayer film sample (Sample A) comprising a 92.25 vinylidene chioride 7.75 methyl acrylate copolymer core layer containing 1.2 weight percent epoxidized soybean oil was prepared and tested as in Example I. The results are shown in Table I.

Comparative Examples B and C

Multilayer film samples (Samples B and C) comprising a 92.25 vinylidene chloride/7.75 methyl acrylate copolymer core layer were prepared and tested as in Comparative Example A except that Samples B and C contained 2.2 weight percent and 4.2 weight percent epoxidized soybean oil, respectively. The results are shown in Table I.

Comparative Example D

The multilayer film of this comparative example was the same as that of Comparative

Examples B and C except that it contained4 percent epoxidized linseed oil and 0.2% epoxidized soybean oil. The multilayer film is tested as in Comparative Example B. The results of the tests are shown in Table I. Table I - Color of PVDC Film

_ . Irradiated vs-

^Samptes Unirradiated

Δb

1 2.7

2 2.7

3 3.3 A 6.1 B 6.2 C 4.5 D 5.0

Example 4

Water, suspending agent (Methocel™ K4M, a product of The Dow Chemical Company) and buffer at a ratio of approximately 1.00/.0009/0.0093 were charged into a reactor. To the mixture in the reactor was added an organic phase consisting of methyl acrylate, vinylidene chloride, t-butyl per-2-ethylhexanoate, and violet pigment at a ratio of 7.72/92.280.369/0.0005. The ratio of water phase to organic phase was 1.25/1.00 The violet pigment was an anthraquinone dyestuff, Macrolex™ Violet B (C.l. Solvent Violet 13), a product of Bayer AG and described in U.S. Patent 2,419,405.

The reaction vessel was sealed and placed in a water bath at 25°C and mixing is begun. The temperature was then raised to a maximum of 84°C over the course of 630 minutes to allow polymerization. The resulting polymer slurry was then cooled, dewatered and dried at 80°C to remove residual water and monomers. The product was then flash molded at a temperature of 165°C for 1 minute at 1000 psi followed by 2 minutes at 20,000 psi. The yellowness of the flash molding as determined according to ASTM method D 1925-70 is shown in Table II.

Comparative Example E

A polymer sample was prepared in the same manner as shown in Example 4 except the Macrolex Violet B dye is omitted. The sample was flash molded and tested in the manner shown in Example 4. The yellowness results are shown in Table II.

Comparative Examples F and G

Polymer samples were prepared in the same manner as shown in Example 4 except the Macrolex Violet B dye was substituted with an equal amount of Macrolex Violet 3R (Comparative Example F) or Macrolex Blue RR (Comparative Example G) dyes. Macrolex Violet 3R and Macrolex Blue RR were examples of dyes which are not sufficiently color stable to withstand the acidic processing environment of PVDC extrusion at about 160°C. Macrolex Violet 3R, a product of Bayer AG, was commercially known as C. I. Solvent Violet 36 and represented by the formula:

Macrolex Blue RR, also a product of Bayer Ag, is commercially known as C. I. Solvent Blue 97 and represented by the formula:

The samples were flash molded and tested in the manner shown in Example 4. The yellowness results are shown in Table II.

Table II - Color of PVDC Moldinα

Yellowness

Sample Index

Example 4 5.3

Comparative Example 12.8

E

Comparative Example 43.9 p

Comparative Example 12.2

G

Example 5 A multilayer film sample composed of outer layers of polypropylene and a core layer of

92.25 weight percent vinylidene chloride/7.75 weight percent methyl acrylate, which contained 1.4% Eastman EPZ plasticizer, an acetylated monoglyceride commercially available form Eastman Chemical, was produced by conventional coextrusion technique. Prior to irradiation, the film was annealed at 120°F for 3 hours to ensure full crystallization of the vinylidene chloride copolymer. The coextruded film was irradiated with 4 Mrad Co-60 gamma radiation at ambient temperature. The PVDC film layer was then separated from the polypropylene layers. Color measurements were taken on the PVDC film prior to irradiation (unirradiated), and immediately after irradiation (irradiated) according to the color measurement procedure. The results of this test, including the change in yellow color (Db), are shown in Table III.

Example 6

2000 grams of the vinylidene chloride copolymer described in Example 5 was added to a Prodex high-intensity mixer. Then 1.00 gram Macrolex B dye was added with mixing over approximately 1 1/2 minutes, resulting in a uniform color concentrate. This color concentrate was then mixed in a tumble blender with an additional quantity of the vinylidene chloride copolymer described in Example 5 at a ratio of 2/98. A multilayer film sample composed of outer layers of polypropylene and a core layer of the vinylidene chloride copolymer color concentrate and vinylidene chloride copolymer was produced by conventional coextrusion technique. The resulting film was annealed, irradiated and color tested in the same manner as in Example 5. The results of color testing are shown in Table III. Comparative Example H

A multilayer film sample composed of outer layers of polypropylene and a core layer of 92.25 weight percent vinylidene chloride/7.75 weight percent methyl acrylate, which contained 1.6% epoxidized soybean oil, was produced by conventional coextrusion technique. The resulting film was annealed, irradiated and color tested in the same manner as in Example 5. The results of color testing are shown in Table III.

Table III

Samples Unirradiated Irradiated Color Chanαe {Δb)

5 2.4 6.1 3.7

6 1.7 5.9 4.2

H 2.3 7.3 5.0

Claims

CLAIMS:

1. A composition comprising a mixture of (1 ) a vinylidene chloride polymer (PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and (2) an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC during and after irradiation of the composition.

2. The composition of Claim 1, wherein the monoethylenically unsaturated monomer is not vinyl chloride.

3. The composition of Claim 1 , wherein the monoethylenically unsaturated monomer is an alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, vinyl chloride, acrylonitrile, or methacrylonitrile.

4. The composition of Claim 1, wherein the aliphatic ester compound is a linear or branched aliphatic ester compound, polymeric aliphatic ester or mixtures thereof, and essentially free of epoxy or aromatic functionality and has a molecular weight of from 300 to 8000.

5. The composition of Claim 4, wherein the monoethylenically unsaturated monomer is methylacrylate, ethylacrylate or methyl methacrylate and the aliphatic ester compound is acetyl tributyl citrate, an acetylated monoglyceride, a diester of adipic, azelaic, sebacic or glutaric acid; a polyester of glycerol or pentaerythritol, or a polymeric adipate, azelate sebacate or glutarate.

6. The composition of Claim 5, wherein the monoethylenically unsaturated monomer is methylacrylate and the aliphatic ester compound is acetylated monoglyceride.

7. The composition of Claim 1, wherein the aliphatic ester compound is present in an amount of from 0.2 to 15 weight percent, based on the weight of the PVDC.

8. The composition of Claim 1 , wherein the aliphatic ester compound is present in an amount of from 0.5 to 10 weight percent based on the weight of the PVDC.

9. The composition of Claim 1, wherein the aliphatic ester compound is present in an amount of from 1 to 4 weight percent, based on the weight of the PVDC.

10. A composition comprising a mixture of (1) a vinylidene chloride polymer (PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and (2) a violet or blue dye which is sufficiently color stable to withstand the acidic processing environment of PVDC extrusion at 160°C, in an amount sufficient to mask color bodies formed during and after irradiation of the composition.

11. The composition of Claim 10, wherein the monoethylenically unsaturated monomer is an alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, vinyl chloride, acrylonitrile, or methacrylonitrile.

12. The composition of Claim 11, wherein the monoethylenically unsaturated monomer is methylacrylate, ethylacrylate or methyl methacrylate.

13. The composition of Claim 12, wherein the monoethylenically unsaturated monomer is methylacrylate

14. The composition of Claim 10 wherein the violet dye is a compound represented by the formula:

15. The composition of Claim 10, wherein the violet or blue dye is present in an amount of from 0.0005 to 0.05 weight percent, based on the weight of the PVDC.

16. The composition of Claim 15, wherein the violet or blue dye is present in an amount of from 0.0007 to 0.01 weight percent, based on the weight of the PVDC.

17. The composition of Claim 16, wherein the violet or blue dye is present in an amount of from 0.001 to 0.005 weight percent, based on the weight of the PVDC.

18. A composition comprising a mixture of (1) a vinylidene chloride polymer (PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, (2) an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC during and after irradiation of the composition and (3) a violet or blue dye which is sufficiently color stable to withstand the acidic processing environment of PVDC extrusion at 160°C, in an amount sufficient to mask the formed color bodies.

19. The composition of Claim 18, wherein the aliphatic ester compound is present in an amount of from 0.2 to 15 weight percent, and the violet or blue dye is present in an amount of from 0.0005 to 0.05 weight percent, both weight percentages based on the weight of the PVDC.

20. A multilayer film comprising at least one layer of a vinylidene chloride polymer

(PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and sandwiched between two or more layers of a polyolefin, wherein the PVDC layer contains an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC layer during and after irradiation of the multilayer film.

21. The multilayer film of Claim 20, wherein the monoethylenically unsaturated monomer is not vinyl chloride.

22. The multilayer film of Claim 20, wherein the monoethylenically unsaturated monomer is an alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, vinyl chloride, acrylonitrile, or methacrylonitrile.

23. The multilayer film of Claim 20, wherein the aliphatic ester compound is a linear or branched aliphatic ester compound, polymeric aliphatic ester or mixtures thereof, and essentially free of epoxy or aromatic functionality and has a molecular weight of from 300 to 8000.

24. The multilayer film of Claim 23, wherein the monoethylenically unsaturated monomer is methylacrylate, ethylacrylate or methyl methacrylate and the aliphatic ester compound is acetyl tributyl citrate, an acetylated monoglyceride, a diester of adipic, azelaic, sebacic or glutaric acid; a polyester of glycerol or pentaerythritol, or a polymeric adipate, azelate sebacate or glutarate.

25. The multilayer film of Claim 24, wherein the monoethylenically unsaturated monomer is methylacrylate and the aliphatic ester compound is acetylated monoglyceride.

26. The multilayer film of Claim 20, wherein the aliphatic ester compound is present in an amount of from 0.2 to 15 weight percent based on the weight of the PVDC.

27. A multilayer film comprising at least one layer of a vinylidene chloride polymer

(PVDC) formed from a monomer mixture wherein the major component is vinylidene chloride and the remainder is at least one monoethylenically unsaturated monomer copolymerizable therewith, and sandwiched between two or more layers of a polyolefin, wherein the PVDC layer contains a violet or blue dye which is sufficiently color stable to withstand the acidic processing environment of PVDC extrusion at 160°C, in an amount sufficient to mask color bodies formed during and after irradiation of the multilayer film.

28. The multilayer film of Claim 27, wherein the monoethylenically unsaturated monomer is not vinyl chloride.

29. The multilayer film of Claim 27, wherein the monoethylenically unsaturated monomer is methyl acrylate.

30. The composition of Claim 27, wherein the violet dye is a compound represented by the formula:

31. The multilayer film of Claim 27 wherein the violet or blue dye is present in an amount of from 0.0005 to 0.05 weight percent based on the weight of the PVDC.

32. The multilayer film of Claim 27 wherein the PVDC layer further comprises an amount of an aliphatic ester compound sufficient to minimize color degradation (formation of color bodies) of the PVDC layer during and after irradiation of the multilayer film.

33. An irradiated multilayer film having at least one layer comprising the composition of Claim 1.

34. An irradiated multilayer film having at least one layer comprising the composition of Claim 10.

35. An irradiated multilayer film having at least one layer comprising the composition of Claim 18.