JPH07168308A - Substrate for photographic printing paper - Google Patents

Abstract

PURPOSE:To provide the substrate for high-quality printing paper without any roll sticking and capable of being easily produced. CONSTITUTION:Water-resistant resin coating layers 2 to 5 are provided on both sides of a base 1 to constitute a substrate for photographic printing paper. In this case, >=2 water-resistant resin coating layers are furnished on the side where an emulsion is applied, and the flexual elastic modulus of the resin to be used for the outermost water-resistant water-resistant resin coating layers 3 and 5 is controlled to 1,000-20,000kgf/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing paper support, and more particularly to a high quality photographic printing paper support which does not cause uneven peeling step due to peeling from a cooling roll during manufacturing.

[0002]

2. Description of the Related Art As a support for photographic printing paper, in order to improve water resistance and light reflection efficiency, the surface of the base paper on which the emulsion is coated is usually coated with a synthetic resin such as a polyolefin resin in which pigments are kneaded and dispersed. The back surface is coated with a synthetic resin such as a polyolefin resin. The coating of base paper such as polyolefin resin is usually done on the running paper,
The molten resin is extruded from a die, sandwiched between a nip roll and a cooling roll, cooled while applying pressure, and then peeled from the cooling roll using a peeling roll.

However, in the above peeling step, the adhesive force becomes uneven between the surface of the polyolefin resin layer and the surface of the cooling roll, and uneven peeling step unevenness (called roll sticking) occurs on the surface of the resin layer. The product in which roll sticking has occurred has no commercial value because the surface smoothness is impaired and the quality of the photographic image is significantly reduced. Also, roll sticking tends to occur continuously in accordance with the rotation cycle of the cooling roll, with unevenness expanding over time, so in order to completely prevent this, the production line is temporarily stopped and the cooling is performed. The roll has to be cleaned, which has a drawback that the production efficiency is significantly reduced.

Therefore, as a method for reducing the occurrence of roll sticking, conventionally, nitrogen gas is blown to the resin surface formed by extruding a molten polyolefin resin on the surface of the base paper to weaken the adhesive force and then contact the cooling roll. Method (for example, Japanese Patent Laid-Open No. 56-89515), a method of spraying mist on the surface of a cooling roll to make water droplets adhere to weaken the adhesive force, or a method of roughening the surface of the cooling roll to weaken the adhesive force. And so on. However, in the case of the above method of spraying nitrogen gas or mist,
There is a drawback that not only a special device is required but also control is complicated, and the method of roughening the surface of the cooling roll has a drawback that the gloss of the surface of the printing paper is lost.

[0005]

The inventors of the present invention have made extensive studies to solve the above-mentioned drawbacks, and as a result, as a water-resistant resin coating layer that comes into direct contact with a cooling roll, the bending elastic modulus is 1,800 kg. / Cm ² or more 20,000 kg
When using a resin of / cm ² or less, no special device is required, and the surface of the cooling roll is not roughened,
The present invention has been completed by finding that a support for photographic printing paper having good quality can be obtained. Accordingly, it is a first object of the present invention to provide a high quality photographic paper support that is free of roll sticking. A second object of the present invention is to provide a support for photographic printing paper which is free from roll sticking and has excellent manufacturing suitability.

[0006]

The above objects of the present invention are to provide a support for photographic printing paper comprising a substrate and a water-resistant resin coating layer on both sides thereof, and at least the water-resistant resin on the emulsion coating side. The coating layer is composed of two or more layers, and at least the flexural modulus of the resin used for the outermost waterproof resin coating layer is 1,800 kgf / cm ² or more 20,0.
Achieved by a support for photographic paper, which is characterized in that it is below 100 kgf / cm ² . In the present invention, the flexural modulus of the resin refers to the flexural modulus measured by the test method of JIS K7203.

The photographic printing paper support of the present invention and the method for producing the same will be described in detail below. In the present invention, the water-resistant resin forming the coating layer on the surface of the base paper is 240 to 3
It can be appropriately selected and used from resins that can be melt-extruded at 40 ° C.
Polyolefin resin such as polypropylene is used. The coating layer may generally be a single layer,
In the present invention, at least the coating layer on the emulsion layer coated surface side is two or more layers.

In the present invention, at least the flexural modulus of the resin used for the outermost layer on the emulsion layer coating surface side is 1,8.
It is necessary is ^{00kgf / cm 2 ~20,000kgf / cm 2} , particularly 2,000kgf / cm ² ~
It is necessary to be 20,000 kgf / cm ² .
When it is less than 1,800 kgf / cm ² , not only the peeling noise increases when the traveling speed of the base paper is 200 m / min or more, but also roll sticking easily occurs,
When it is 20,000 kgf / cm ² or more, the flexibility as a printing paper is lost.

The flexural modulus is 1,800 kgf / cm ² ~
As the 20,000 kgf / cm ² resin, an appropriate one can be selected from the above polyolefin-based resins, and among these, low density polyethylene,
It is preferably at least one selected from the group of linear low-density polyethylene, high-density polyethylene, polypropylene, polyethylene terephthalate, a mixture of these resins, and a resin obtained by mixing these resins with another polyolefin resin. . Examples of the other polyolefin-based resin include ethylene ethyl acrylate and ethylene methyl acrylate.

The resin that comes into contact with the cooling roll is the amount of the molten resin extruded from the die, the extrusion temperature, the base paper running speed,
It may be appropriately determined in consideration of the surface temperature and surface shape of the cooling roll, the material, the pressure of the nip roll, the rigidity of rubber, the material of the peeling roll and its position, and the like. Therefore, the back side does not necessarily have to be the same as the coating layer on the emulsion coating side.

In the present invention, at least one of the water-resistant resin coating layers on the emulsion coating side is provided with an inorganic pigment such as titanium dioxide, a bluing agent, and a fluorescent whitening agent from the viewpoint of improving the image quality. It is preferable to contain an agent or the like. The bottommost waterproof resin coating layer in contact with the substrate may contain a tackifier resin, an adhesive resin or the like from the viewpoint of improving the adhesiveness to the base paper. Further, in addition to the above, an antioxidant, a release agent, a hollow polymer, etc. may be appropriately contained depending on the application.

The form of the titanium dioxide may be either anatase type or rutile type, but it is preferable to use the anatase type when whiteness is prioritized, and when sharpness is prioritized. It is preferable to use the rutile type. In consideration of both whiteness and sharpness, anatase type and rutile type may be blended and used,
The titanium dioxide-containing layer may be two layers, one layer may be added with anatase type titanium dioxide and the other layer may be added with rutile type titanium dioxide.

The average particle size of titanium dioxide is 0.1-0.1.
The range is preferably 0.4 μm. When the average particle size is less than 0.1 μm, it becomes difficult to uniformly mix and disperse in the resin layer, while when it exceeds 0.4 μm, sufficient whiteness cannot be obtained and projections are formed on the surface of the upper coating. Occurs, which adversely affects the image quality. Examples of titanium dioxide having such a morphology and an average particle size include, for example, trade names KA-10 and KA-20 manufactured by Titanium Industry Co., Ltd. and trade names A-100 and A-22 manufactured by Ishihara Sangyo Co., Ltd.
0, PF-656, PF-654, PF-671, PF
-715, CR-63 and the like.

As the titanium dioxide, in order to suppress its activity and prevent yellowing, its surface is generally surface-treated with an inorganic substance such as aluminum oxide hydroxide or silicon oxide hydroxide, polyhydric alcohol or polyvalent amine. It is possible to use those which have been surface-treated with an organic substance such as metal soap, alkyl titanate and polysiloxane, and those which have been surface-treated in combination with a treatment agent for an inorganic substance / organic substance. These treating agents are 0.2 to 2.0% by weight with respect to titanium dioxide in the case of an inorganic substance, and 0.1% in the case of an organic substance.
It is preferable to use in the range of 1.0 wt% to 1.0 wt%.

Titanium dioxide is used in a water-resistant resin by a kneading machine such as a two-roll, three-roll, kneader or Banbury mixer using a higher fatty acid, a metal salt thereof, a higher fatty acid ethyl or a higher fatty acid amide as a dispersion aid. Be kneaded into. The resulting titanium dioxide-containing water resistant resin is molded into a pellet shape and used as a titanium dioxide masterbatch.

The content of titanium dioxide in the pellet is generally preferably about 30 to 75% by weight, and the dispersion aid is generally contained in about 0.5 to 10% by weight based on the amount of titanium dioxide. It is preferable. If the content of titanium dioxide is less than 30% by weight, the resolution will be insufficient and 75
If the content is more than weight%, cracking tends to occur when bent.

Examples of the bluing agent include generally known ultramarine blue, cobalt blue, cobalt oxide phosphate, quinacridone pigment, and the like, and mixtures thereof. The particle size of the bluing agent is usually preferably in the range of 0.3 to 10 μm.

When the bluing agent is used in the outermost layer, it is 0.2 to 0.4% by weight, otherwise 0 to 0% by weight.
It is preferably contained in the range of 0.15% by weight. The bluing agent is 2 rolls, 3 rolls, kneader,
It is kneaded into the waterproof resin with a kneading machine such as a Banbury mixer. The water-resistant resin containing the bluing agent thus obtained is molded into a pellet shape and used as a masterbatch of the bluing agent. The bluing agent content in the pellet is preferably about 1 to 30% by weight.

Titanium dioxide may be kneaded together when forming the bluing agent pellet, and a low molecular weight water-resistant resin, higher fatty acid, or a metal salt thereof may be added in order to aid dispersion of the bluing agent. , Higher fatty acid ester,
Dispersion aids such as higher fatty acid amides can be used.
The content of the antioxidant that can be contained in the waterproof resin layer is 50 to 1,000 with respect to the waterproof resin amount.
It is preferably about ppm. The masterbatch containing the titanium dioxide and / or the bluing agent thus produced is appropriately diluted with a water resistant resin,
Used for coating.

The tackifier resin is appropriately selected from rosin derivative resins, terpene resins (for example, polymer β-pinene), coumarone-indene resins, petroleum hydrocarbon resins and the like. These may be used alone or in combination of two or more. Specific examples of the petroleum hydrocarbon resin include aliphatic petroleum resin, aromatic petroleum resin, dicyclopentadiene petroleum resin, copolymer petroleum resin, hydrogenated petroleum resin and alicyclic petroleum resin. Is mentioned. The aliphatic petroleum resin preferably has 5 carbon atoms,
The aromatic petroleum resin is particularly preferably one having 9 carbon atoms.

The amount of such tackifier resin compounded is in the range of 0.5 to 60% by weight based on the water resistant resin.
It is preferably in the range of 10 to 35% by weight. If the compounding amount of the tackifier resin is less than 0.5% by weight, the adhesion will be poor, and if it exceeds 60% by weight, neck-in during production will easily occur.

Examples of the adhesive resin that can be heat-sealed with the water resistant resin include ionomer, ethylene vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer, and metal salts thereof. . The content of the adhesive resin is 20 to 500% by weight, preferably 50 to 200% by weight, based on the water resistant resin. The tackifier resin and the adhesive resin may be used together.

In the present invention, the water-resistant resin layer is made of paper, synthetic paper or the like which is made of the above-mentioned resin melted by heating or, if necessary, the resin melted of pellets containing titanium dioxide and / or bluing agent. It can be formed on the substrate by either a sequential laminating method or a multi-layer laminating method using a multi-layer extrusion die such as a foot block type, a multi-manifold type or a multi-slot type. In the present invention, the multi-layer laminating method is used. Is preferably used.

The shape of the multilayer extrusion die is not particularly limited, but a T die, a coat hanger die and the like are generally preferably used. Water resistant resin is 240 ~ 340 ℃
It is preferable that the laminate film is formed by melt-extruding into a film form from the slit die in a short time within the temperature range of. If the melt extrusion temperature is lower than 240 ° C., the oxidation of the water resistant resin becomes insufficient and the adhesion between the water resistant resin layers decreases. On the other hand, when the temperature exceeds 340 ° C, film cracks and die lip streaks occur, and the appearance of the product is significantly impaired.

Before the resin is coated on the substrate, the substrate is preferably subjected to activation treatment such as corona discharge treatment, flame treatment, glow discharge treatment, or plasma treatment. When the multilayer waterproof resin coating layer of the present invention is composed of, for example, three layers, the thickness of the uppermost layer is 0.5 to 50 μm, the thickness of the intermediate layer is 5 to 50 μm, and the thickness of the lowermost layer is It is preferably 0.5 to 10 μm.

The outermost surface of the water-resistant resin coating layer on the emulsion coating side has a glossy surface, or a fine surface, a matte surface or a silk surface as described in JP-A-55-26507, and the back surface is not formed. Shape the glossy surface. Therefore, when coating the waterproof resin coating layer on the back surface side, it is simple and preferable to use a cooling roll having a roughened surface. An activation treatment such as a corona discharge treatment or a flame treatment can be applied to the surface after the patterning, and after the activation treatment, JP-A-61-61
It is also possible to perform the subbing process as described in Japanese Patent Publication No. 846443.

As the substrate used in the present invention, natural pulp paper containing normal natural pulp as a main component, mixed paper consisting of natural pulp and synthetic fiber, synthetic fiber paper containing synthetic fiber as a main component, polystyrene, Any of so-called synthetic papers obtained by quasi-synthesizing a synthetic resin film such as polypropylene may be used, but natural pulp paper (hereinafter simply referred to as base paper) is particularly preferably used as a substrate for photographic printing paper.

As the chemicals to be added to the base paper, in addition to alkyl ketene dimer, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, higher fatty acid salts, paraffin wax, alkenyl succinic acid and the like size agents, polyacrylamide A paper-strengthening agent such as the above, a fixing agent such as a sulfuric acid band, or the like is used. Other,
If necessary, dyes, fluorescent dyes, slime control agents, defoaming agents, etc. are added.

If necessary, the following softening agents can be added. With respect to the softening agent, for example, New Paper Processing Handbook (edited by Shiyaku Time Co., Ltd.), pages 554 to 555 (198)
Although it is possible to use those described in "Year 0", those having a molecular weight of 200 or more are particularly preferable. This softening agent has a hydrophobic group having 10 or more carbon atoms and is an amine salt or a quaternary ammonium salt that self-fixes with cellulose.

Specific examples of the softening agent include a reaction product of a maleic anhydride copolymer and a polyalkylene polyamine, a reaction product of a higher fatty acid and a polyalkylene polyamine, and a reaction product of a urethane alcohol and an alkylating agent. Examples thereof include quaternary ammonium salts of higher fatty acids, and it is particularly preferable to use a reaction product of a maleic anhydride copolymer and a polyalkylene polyamine and a reaction product of a urethane alcohol and an alkylating agent.

The pulp surface may be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, or a modified product of polyvinyl alcohol. Examples of the modified product of polyvinyl alcohol in this case include a modified product of a carboxyl group, a modified product of silanol, and a copolymer with acrylamide.

The coating amount of the film-forming polymer is 0.
1 to 5.0 g / m ² , preferably 0.5 to 2.0 g / m
Prepared to ² . If necessary, an antistatic agent, a fluorescent whitening agent, a pigment, an antifoaming agent and the like can be added to the film-forming polymer.

The base paper is prepared by making a pulp slurry containing the above-mentioned pulp and additives such as fillers, sizing agents, paper strengthening agents, and fixing agents added as necessary with a paper machine such as a Fourdrinier paper machine. Manufactured by drying, rolling up. Either before or after the drying, the surface size treatment is performed, and the calendar treatment is performed between the drying and the winding.

When the surface sizing treatment is carried out after drying, the calendering treatment can be carried out either before or after the surface sizing treatment, but the calendering treatment is carried out in the final finishing step after various treatments have been carried out. Preferably. As the metal roll or elastic roll used in the calendering process, known rolls used in the production of ordinary paper are used. The base paper used for the support for photographic printing paper of the present invention is finally adjusted to a film thickness of 50 to 250 μm by the above-mentioned calendering treatment. The density of the base paper is 0.8 to 1.3 g / m ³ , preferably 1.0 to
It is 1.2 g / m ³ .

The support for photographic printing paper in the present invention includes
Various back coat layers can be provided for the purpose of preventing electrification and curling. Further, the backcoat layer has Japanese Examined Patent Publication Nos. 52-18020, 57-9059, 57-53940, 58-56859,
JP-A-59-214849, JP-A-58-18414
Inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants and the like, which are described or exemplified in each publication such as No. 4 and the like, can be contained in appropriate combination.

The support for photographic printing paper in the present invention is coated with various photographic constituent layers to provide color photographic printing paper, black-and-white photographic printing paper, typesetting photographic paper, reverse photographic material, silver salt diffusion transfer negative and positive. It can be used for various purposes such as printing materials. As the photographic constituent layer, for example, an emulsion layer of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide or the like can be provided. It is also possible to provide a color coupler in the silver halide photographic emulsion layer to provide a multilayer silver halide color photographic constituent layer. The silver salt diffusion transfer image-receiving layer can be provided by incorporating a physical phenomenon nucleus.

[0037]

INDUSTRIAL APPLICABILITY In the support for photographic printing paper of the present invention, at least the flexural modulus of the resin used in the outermost waterproof resin coating layer is 1800 kg / cm ² or more and 20,000 kg /
Since it is cm ² or less, it does not require a special device and can be manufactured without causing roll sticking even if the surface of the cooling roll is not roughened. Therefore, the photographic printing paper is excellent in quality. It is a support for. Also,
In the production of the photographic printing paper support of the present invention, since roll sticking does not occur, it is not necessary to stop the production line, and the production efficiency is excellent.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Example 1. A polyethylene roll having the composition shown in Table 1 below was melted using a cooling roll having a surface mat roughness of 7 μm on the back surface of the paper substrate 1 having a width of 50 cm and an average weight of 168 g / m ² which was treated by corona discharge with an output of 1 kW. Multi-layer extrusion lamination was performed at a temperature of 325 ° C. and a line speed of 200 m / min, and water-resistant resin layers 2 and 3 of polyethylene resin having a thickness of 13 μm were respectively provided (see FIG. 1).

[0040]

[Table 1]

Next, a cooling roll having a surface mat roughness of 0.2 μm was used on the front surface of the paper substrate 1 on which the emulsion was coated.
The composition, conditions, and melting temperature shown in Table 2 below were set at a melt temperature of 325 ° C. and a line speed of 200 m / min, and multilayer extrusion lamination was performed to provide water resistant resin layers 4 and 5 to prepare a photographic paper support (see FIG. 1). .

[0042]

[Table 2]

Example 2. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 3 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. And the water resistant resin layers 4, 5 and 7 under the conditions
Was provided to prepare a support for photographic printing paper (see FIG. 2).

[0044]

[Table 3]

Example 3. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 4 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. Under the above conditions, the water resistant resin layers 4 and 5 were provided to prepare a support for photographic printing paper (see FIG. 1).

[0046]

[Table 4]

Example 4. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 5 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. And the water resistant resin layers 4, 5 and 7 under the conditions
Was provided to prepare a support for photographic printing paper (see FIG. 2).

[0048]

[Table 5]

Example 5. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 6 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. And the water resistant resin layers 4, 5 and 7 under the conditions
Was provided to prepare a support for photographic printing paper (see FIG. 2).

[0050]

[Table 6]

Example 6. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 7 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. And the water resistant resin layers 4, 5 and 7 under the conditions
Was provided to prepare a support for photographic printing paper.

[0052]

[Table 7]

Comparative Example 1. After the water resistant resins 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 8 below was applied to the front surface of the paper substrate 1 which was the emulsion coating side. Under the above conditions, a single layer of the water resistant resin layer 4 was provided to produce a support for photographic printing paper (see FIG. 3).

[0054]

[Table 8]

Comparative Example 2. After providing the coating layers 2 and 3 of the polyethylene resin on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 9 below was applied to the front surface of the paper substrate 1 on the emulsion coating side. Under the conditions, provide a single layer of water resistant resin layer,
A support for photographic printing paper was prepared (see FIG. 3).

[0056]

[Table 9]

Comparative Example 3. After the water resistant resins 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 10 below was applied to the front surface of the paper substrate 1, which was the emulsion coating side. And water-resistant resin layer 4 under the conditions
To prepare a support for photographic printing paper (see FIG. 3).

[0058]

[Table 10]

Comparative Example 4. After the water resistant resin layers 2 and 3 of polyethylene resin were provided on the back surface of the paper substrate 1 in the same manner as in Example 1, the composition shown in Table 11 below was formed on the front surface of the paper substrate 1 on the emulsion coating side. Under the above conditions, the water resistant resin layers 4 and 5 were provided to prepare a support for photographic printing paper (see FIG. 1).

[0060]

[Table 11]

Table 12 shows the results of Examples 1 to 6 and Comparative Examples 1 to 4. With regard to roll sticking, peeling unevenness on the surface of the resin layer peeled off from the cooling roll was visually observed, and those within the allowable range were evaluated as ◯, slightly inferior as Δ, and inferior as x. Regarding the adhesiveness with the paper base, ○ when the paper base is completely adhered to the resin layer,
When the paper base was partially adhered to the resin layer, the evaluation was Δ, and when the resin layer and the paper base were delaminated, the evaluation was X.

[0062]

[Table 12]

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view of a photographic printing paper support of the present invention.

FIG. 2 is a schematic partial cross-sectional view of a support for photographic printing paper of the present invention in which the water-resistant coating layer on the emulsion side has three layers.

FIG. 3 is a schematic partial cross-sectional view of a support for photographic printing paper of a comparative example in which the water-resistant coating layer on the emulsion side is one layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Water resistant resin coating layer 3 Water resistant resin coating layer in contact with a cooling roll 4 Water resistant resin coating layer 5 Water resistant resin coating layer in contact with a cooling roll 6 Emulsion layer 7 Water resistant resin coating layer

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Claims (3)

[Claims] 1. A photographic printing paper support comprising a substrate and water-resistant resin coating layers on both sides thereof, wherein at least the water-resistant resin coating layer on the emulsion coating side comprises two or more layers, and at least: A support for photographic printing paper, wherein the flexural modulus of the resin used for the outermost waterproof resin coating layer is 1800 kgf / cm ² or more and 20,000 kgf / cm ² or less. 2. The resin used for the outermost waterproof resin coating layer is low density polyethylene, linear low density polyethylene,
At least one selected from the group consisting of high-density polyethylene, polypropylene, polyethylene terephthalate, a mixture of these resins, and a resin obtained by mixing these resins with another polyolefin resin.
The support for photographic printing paper according to 1. 3. The support for photographic printing paper according to claim 1, wherein the waterproof resin layer composed of two or more layers is provided by multilayer extrusion lamination.