JPS63233836A - Barriering film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plastic film with excellent water vapor barrier properties and gas barrier properties.

[Prior Art] Conventionally, as a method of imparting water vapor barrier properties and gas barrier properties to plastic films, a method has been used in which a vinylidene chloride-based resin having degraded water vapor barrier properties and gas barrier properties is composited. Showa 48-40
882, 50-3484, etc.).

[Problems to be solved by the invention] Vinylidene chloride resins are generally not composited by melt extrusion because their melting temperature and thermal decomposition temperature are very close to each other. Coating is commonly performed. However, in order to obtain sufficient barrier properties, it is necessary to increase the thickness of the vinylidene chloride resin layer, but since it is not possible to coat it thickly enough with one coat, the required coating thickness can be achieved by multiple coats. The method used was to obtain it. However, even if you apply multiple coats, the coating thickness per coat needs to be considerably thicker, so it takes time to dry, making it impossible to increase the coating speed, and it is necessary to pass the coater through the coater many times to apply multiple coats. For reasons such as
There was nothing I could do.

The object of the present invention is to provide an inexpensive barrier film that does not have the above-mentioned drawbacks, that is, it is provided with a coating layer that exhibits sufficient properties even when applied thinly.

[Means for Solving the Problems] The present invention provides at least one side of a plastic film,
Swellable layered silicate (a) and vinylidene chloride resin (b)
) in a weight ratio (a/b) of 2 to 1/100.

As the base plastic film in the barrier film of the present invention, any known plastic film may be used as appropriate. Typical examples include polyester film, triacedel cellulose film, cellophane film,
Examples include polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyether sulfone film, aromatic polyamide film, polysulfone film, and polyolefin film. However, from the viewpoint of mechanical properties and cost, it is particularly preferable to use polyester film, polycarbonate film, or polyphenylene sulfide film. The thickness of the plastic film is not particularly limited, but is usually 0.1 μm or more and 500 μm or less.

When using a composite film as a base film, the number of layers or the method is not particularly limited, but composite extrusion, extrusion lamination on the base film, lamination using various adhesives, etc. This is usually done.

The essence of the present invention is to use a swellable inorganic layered silicate (a) as a barrier layer component. Here, the term "swellable" refers to an inorganic layered silicate that has the property of "swelling" by coordinating water between the layers, and the coating layer of the coating film of the present invention utilizes this swelling property to at least partially Its essence is that it exists in the form of fine particles formed by interlayer separation.

The swellable inorganic layered silicate (a) used in the present invention is structurally SiO+ and has a theoretical tetrahedral 3i to O ratio of 2:
The phyllosilicate No. 5 has a crystal structure in which the crystal unit cell is repeated in the thickness direction, and a typical example thereof can be expressed by the following chemical formula.

'A10.3~1. tX+. t~s. t(5r*.s
, -4. scl+o) Z+. g ~ x. z where W: interlayer ion, one or more cationic ions X: ion at octahedral position, MCI2+ or Mg2
The local part is Ll, Fe2+, N12+, M n 2 +
, Au3+ and Fe3+ ion substituted with at least one ion selected from the group consisting of O: oxygen Z: one or two ions selected from F- or OH-. body position s i4+ is Ge4+
Or some of these are AD,”, F e 3+, B3+W
The swellable inorganic layered silicate referred to in the present invention includes these as well.

Specific examples of these include clay-based and mica-based minerals such as natural products such as montmorillonite and vermiculite, and synthetic products such as tetrasilisic mica, taeniolite, and hectorite, which are synthesized by melting or hydrothermally and have the general formulas mentioned above. is.

Among these, synthetic materials are particularly preferred because they contain few impurities and have a uniform composition, resulting in uniform crystals.Among them, W7- is preferred because it has excellent crystal flatness and a large crystal size. o. +~X ”Q・l Mj2.9-x-3.2
-x L;x (Si 1.B , 4, OQro')F
H, g +2.0 or 'A'x-o. +p-x+o. t Mg y , v−x
-y,z-Aixc Si s. h-wtoOlo)
(OH) +, 9-2. .

(However, X=0.8 to 1.2) is preferable. The interlayer ions W are not particularly limited as long as they are one or more cationic ions, but examples of cationic ions include Ll and Na.

/R2+ Rt-N-R3 (However, R1 has 7 or more carbon atoms\R.

50 or less alkyl group, R2-R4 are hydrogen or carbon number 1
~10 alkyl groups), K, or Mg++, Ca
Examples include alkaline earth metals such as ++, Ba++, and Aff+++. Among them, R2'' R1-N-R3 or Ll accounts for 40% or more, preferably 60% or more, more preferably 80% or more and 90% or more of the gold interlayer ion\R4 because it has particularly good dispersibility in water. It is preferable if there is.

The size of the swellable inorganic layered silicate is not particularly limited, or the average particle size measured by a sedimentation method is 0.05 μm to 1.0 μm.
When the thickness is in the range of 5 μm, preferably 0.1 μm to 8 μm, more preferably 0.15 μm to 3 μm, it is preferable because a uniform layer of 1 q can be formed. Also, 50% of all particles
, preferably 80%, more preferably 90% of the thickness is 8
A thickness of 00 Å or less, preferably 400 Å or less, and more preferably 100 Å or less is more preferable because the surface of the coating layer becomes smooth. The thickness herein refers to the thickness of inorganic particles present in the cross section of the coating layer of the coating film.

The vinylidene chloride resin (b) in the present invention is not particularly limited as long as it is a resin copolymerized with vinylidene chloride by a known method.
Typical examples include vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylic acid ester copolymer, vinylidene chloride-methacrylic acid ester copolymer, etc. . Among them, the base plastic film,
Particularly preferred are vinylidene chloride-acrylonitrile copolymer and vinylidene chloride-acrylic acid ester copolymer from the viewpoint of adhesion to PET-80 film. A ternary or quaternary copolymer containing these in combination with acrylic acid, methacrylic acid, crotonic acid, etc. may also be used. The ratio of vinylidene chloride and the copolymer component to 100 parts by weight of vinylidene chloride is 100 parts by weight or less and 2 parts by weight or more, preferably 30 parts by weight or more and 5 parts by weight or less, and the adhesion to the base plastic film is improved. It is suitable in terms of gender.

The vinylidene chloride copolymer only needs to have a degree of polymerization that allows it to form a film by itself, and the weight average molecular weight is 50.
000,000 to 1,000,000, preferably 20,000 to 800,000. The vinylidene chloride copolymer may be dissolved in a general-purpose organic solvent or emulsified.

Swellable layered silicate <a> and vinylidene chloride resin (b
) are mixed with various substances, such as organic solvents, antistatic agents, ultraviolet absorbers, pigments, dyes, and inorganic particles such as silicon oxide and titanium oxide, to the extent that they do not impair the properties of the layer. It's okay.

The thickness of the mixed layer in the present invention is not particularly limited, but is usually 0.03 μm to 30 μm, preferably 0.2 μm to 1
0 μm1, more preferably 0.5 to 5 μm.

In the present invention, the swellable layered silicate (a) and the vinylidene chloride resin (b) are used at a ratio (a/b) of 2 to 1/100.
It is necessary to mix them in a certain ratio. This is the weight ratio (
If a/b) is larger than 2, the strength of the coating film decreases, which is undesirable. On the other hand, if it is smaller than 1/100, the effect of significantly improving barrier properties is lost, which is not preferable. Moreover, when the weight ratio (a/b) is 1/2 to 1/15, it is preferable because the balance between coating film toughness and barrier properties becomes particularly suitable.

Next, a method for manufacturing the laminated film of the present invention will be explained.

First, prepare a plastic film as a base material. After subjecting the film to corona discharge treatment and anchoring treatment with acrylic resin, urethane resin, etc., as necessary, a layer consisting of a swellable layered silicate and vinylidene chloride (as described in the present invention) is added using a known method. It can be obtained by coating using a kiss coater, a die coater, a reverse coater, a gravure coater, a spray coater, a bar coater, or the like. In addition, when coating a stretched film such as polyester film, polypropylene, polyphenylene sulfide, etc., it goes without saying that the film may be stretched and further heat treated after being coated on a film that has been subjected to necessary surface treatment.

[Function] In the present invention, a mixed layer of vinylidene chloride and swellable layered silicate, which is scales with an extremely high aspect ratio and also has excellent barrier properties itself, is used as a barrier layer. The barrier properties are greatly improved because the length of the path required for molecules such as water vapor and oxygen to permeate through the barrier layer is dramatically increased.

Method for Measuring Characteristics and Evaluating Effects Methods for measuring characteristic values and evaluating effects of the present invention are as follows.

■ Oxygen barrier property: According to ASTM-D-1434, 25℃, 100%RH
It was measured with However, the unit is CC/Tn2・24hr・
The film thickness is 0.1 mm.

■ Adhesion: A commercially available cellophane adhesive tape with a length of 5 cm and a width of 2.5 cm (manufactured by Chiban Co., Ltd.) was attached to the coating layer and peeled off at 90°. The oxygen barrier properties of the samples were measured, and those whose values did not change were evaluated as "○", and those whose values significantly deteriorated were evaluated as rXJ.

[Example] The present invention will be explained based on examples.

Examples 1 to 5, Comparative Examples 1 to 5 First, a biaxially stretched polyester film was prepared as a base film, and a barrier layer having the following composition was coated on the coating surface with a thickness of 0. Coat to a thickness of 5 μm. However, after coating, the coating was dried in a hot air oven at 100° C. for 1 minute, and then heat-treated at 150° C. for another minute.

622 Riri 1 The following four types (a) to (d) were used as inorganic particles.

(a) Lithium Duolite (L 1fVtQz Li (S i 4010)
F2) However, the average particle size determined by the sedimentation method is 0.6 μm.

(b) Thyroid However, the average particle size determined by the sedimentation method is 0.8 μm.

(C) Colloidal silica However, the average particle size determined by the sedimentation method is 0.6 μm.

(d) Muscovite However, the average particle size determined by the sedimentation method is 0.8 μm.

As the nylidene chloride resin, Mitsubishi Pardish (
"Diofan" 207DC manufactured by Co., Ltd. is used. Moreover, the mixing ratio is shown in the table.

As shown in the table, it can be seen that excellent properties are exhibited only when the amount added is within the range of the present invention or when a swellable layered silicate is used. In particular, it can be seen that when the weight ratio (a/b> is 1/2 to 1/15), a remarkable effect is exhibited and it is suitable.

[Effects of the Invention] The present invention provides at least one side of the plastic film,
By providing a layer containing a mixture of swellable layered silicate and vinylidene chloride, the following excellent effects were achieved.

■ High barrier properties can be obtained by simply applying a thin layer of cloth.

■ To obtain the same barrier properties, it is only necessary to apply a thin layer, resulting in a colorless and transparent film without the color tone characteristic of Nylidene.

■ Since the amount of vinylidene has been reduced, the generation of chlorine gas during recovery and incineration will be reduced.

The thus obtained barrier film of the present invention can be used in general applications that require various barrier properties such as water vapor barrier properties and oxygen barrier properties, but it can be used at low cost because it only needs to be thinly coated. Particularly suitable for the required applications.

Claims (1)

[Claims] On at least one side of the plastic film, a layer made of a resin obtained by mixing a swellable layered silicate (a) and a vinylidene chloride resin (b) at a weight ratio (a/b) of 2 to 1/100 was provided. A barrier film characterized by: