JPH01313536A - Barrier 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 excellent water vapor barrier properties and gas barrier properties is composited. 48-40
882, 50-3484, etc.).

[Problems to be Solved by the Invention] Generally, the melting temperature and thermal decomposition temperature of vinylidene chloride resins are very close to each other, so compounding by melt extrusion is not often carried out, and coating in a state in which they are dispersed in a solvent or water is difficult. It is commonly practiced. 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 multiple coats are applied, the coating thickness per coat needs to be considerably thicker, so it takes time to dry, the coating speed cannot be increased, and it is necessary to pass the coater through the coater many times to apply multiple coats. For some reasons, it was not possible to obtain cheap products.

In addition, when layered silicate is simply dispersed in vinylidene chloride resin, although it is effective for gas barrier properties, the toughness of the coating film deteriorates, i.e., cohesive failure of the coating film occurs, resulting in processing into bags. There were drawbacks such as poor adhesion of the seal part.

The object of the present invention is to provide an inexpensive barrier film that does not have the above-mentioned drawbacks, that is, has sufficient properties when applied thinly, and has five coating layers with excellent coating film adhesion. It is something.

[Means for Solving the Problems] The present invention provides a plastic film with a swellable layered silicate (a) and a vinylidene chloride resin (b) on at least one side of the plastic film.
and a polymer (c) having one or more reactive groups, wherein between the layers of the swellable layered silicate there is a cation-forming group and one or more reactive groups. A compound having a reactive group exists, and the weight ratio (a>/(c) is 1
The main points are that the ratio is 0 to 1/10 and (a)/(b) is 2 to 1/100.

As the base plastic film used in the barrier film of the present invention, any known plastic film may be used as appropriate. Typical examples include polyester film, polycarbonate film, triacetylcellulose film, cellophane film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyethersulfone film, aromatic polyamide film, polysulfone film, and polyolefin film. etc. can be mentioned. 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
It is not less than μm and not more than 500 μm.

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, or lamination using various adhesives, etc. Usually, they are combined.

If the adhesion between the coating layer and the base film in the present invention is poor, the coated side of the base film may be subjected to corona discharge treatment in various atmospheres (air, nitrogen gas, carbon dioxide gas, etc.), or
It is preferable to carry out the anchor treatment using a common anchor treatment agent such as an acrylic resin or a urethane resin.

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 S i 04 and is a phyllosilicate in which the ratio of 3i to O of the tetrahedron is theoretically 2:5, and the crystal unit cell is in the thickness direction. It has a repeated crystal structure, and a typical example thereof can be represented by the following chemical formula.

wo, 3~1.1 xi, a~3.2 (S'3.5
~4.5010)71.8~2,2 Here, W: is an intercalation compound, and is an ion of one or more cationic compounds X at a dihedahedral position, Mq2+ or MCI
A part of l−+, Fe2”, N i2+, M n 2
+, 2+ A9 and at least 3+ ions substituted with one type of ion selected from the group consisting of Fe3+ O: oxygen Z: one or two types of ions selected from F- or OH-; So, s i4+ at the above tetrahedral position is 4+
3+ 3+
+Ge or some of these are Aβ, Fe, B
etc., and the swellable inorganic layered silicate referred to in the present invention also includes these.

Specific examples of these include clay-based materials such as natural products such as montmorillonite and vermiculite, and synthetic materials such as tetrasilicic mica, duolite, and hectorite, which are synthesized by melting or hydrothermally having the above-mentioned formula, and mica. There are minerals.

Among these, synthetic materials are particularly preferred because they contain few impurities and have a uniform composition, resulting in uniform crystals.Among them, Wx- is particularly preferred because it has excellent crystal flatness and a large crystal size. 0.1~x +0.1Mg2.8-x ~3.2
-x ” x (Si3.5~4.0010) Fl, 8
~2.0 or Wx -0,1~x +0.1Mq2.8-x ~3.
2-X”X(Si3.5~a,o010)(OH
) 1.8 to 2.0 (however, x=0.8 to 1.2) is preferable.

The intercalation compound W is not particularly limited as long as it has one or more cation-forming groups and one or more reactive groups, but preferred examples include N,N-diethylethanolamine, N,N-dimethyl Hydrochloride of amino alcohols such as ethanolamine, aminoethylethanolamine, N-methyl-N, N-jetanolamine, N,N-diisopropylethanolamine, N,N-dibutylethanolamine, N-methylethanolamine, Examples include choline chloride, dimethyl-p-phenylenediamine hydrochloride, N-1-naphthylethylenediamine dihydrochloride, hydroxylamine hydrochloride, phenylhydrazinium chloride, and the like.

Among these, it is preferable that choline chloride accounts for 40% or more, preferably 60% or more, and more preferably 80% or more of the total intercalation compounds since it has particularly good dispersibility in water.

The size of the swellable inorganic layered silicate is not particularly limited, but the average particle diameter measured by a sedimentation method is 0.05 μm to 0.05 μm.
A thickness in the range of 15 μm, preferably 0.1 μm to 8 μm, more preferably 0.15 μm to 3 μm is preferable because a uniform layer can be obtained. Also, 50% of all particles
, preferably 80%, more preferably 90% of the thickness is 8
It is more preferable to have a thickness of 00 Å or less, preferably 400 Å or less, more preferably 100 Å or less, 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 monomer 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,
In particular, vinylidene chloride-acrylonitrile copolymer and vinylidene chloride-acrylic acid ester copolymer are preferred from the viewpoint of adhesion to PET-80 film and barrier properties. A ternary or quaternary copolymer containing acrylic acid, methacrylic acid, crotonic acid or the like may also be used. The ratio of vinylidene chloride and copolymerized components is 1 to 1 vinylidene chloride.
When the copolymerization component is 100 parts by weight or more and 2 parts by weight or more, preferably 30 parts by weight or more and 5 parts by weight or more based on 00 parts by weight, it is preferable in terms of adhesion to the base plastic film and the toughness of the coating film. be.

The vinylidene chloride copolymer may have a degree of polymerization sufficient to form a film by itself, and has a weight average molecular weight of 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.

The polymer having one or more reactive groups as used in the present invention is
It is not particularly limited as long as it can react with the reactive group of the compound of the swellable layered silicate. The reactive group can be arbitrarily selected depending on the reactivity with the intercalation compound, but it is preferable that the reactive group has at least one type of aqueous group, carboxyl group, amine group, etc. at the molecular terminal or side chain. Furthermore, when using a swellable layered silicate swollen with a vinylidene chloride resin emulsion and water, a polymer that dissolves or disperses in water is preferred, and such polymers include polyvinyl alcohol, cellulose resin, Examples include acrylic resin emulsions and polyester copolymers having hydrophilic groups. Various substances such as organic solvents, antistatic agents, ultraviolet absorbers, pigment,
Dyes, inorganic particles such as silicon oxide, titanium oxide, etc. may be added to the extent that they do not impair the properties of the layer.

In the present invention, the swellable layered silicate (a), the vinylidene chloride resin (b), and the polymer (c) having one or more reactive groups have a weight ratio of (a)/(c) of 10 to 1. /10
, and (a>/(b) must exist in a ratio of 2 to 1/100. This means that (a)/(c) is 10
If it is larger than (a>/ (b) is larger than 2, the cohesive failure strength of the coating film will decrease, which is undesirable.
a)/(c) is 1/10, (a>/(b) is 1/100
If it is less than , the effect of significantly improving barrier properties is lost, which is not preferable. When (a)/(c) is 2 to 1/3 and (a)/(b) is 1/2 to 1/15, the balance between cohesive failure strength and barrier properties of the coating film is particularly favorable. preferable.

The thickness of the coating layer is not particularly limited, and is usually 0.1
~10tim, preferably 0.3-5μm.

More preferably, the thickness is 0.5 to 3 μm, and if the laminate requires transparency, a thinner film is preferred. Further, when the barrier film of the present invention is used as a packaging material, a heat-sealable thermoplastic resin layer can be provided on one side as necessary. Heat-sealable thermoplastic resins include polyethylene, polypropylene,
polyolefins such as ethylene-propylene copolymers,
Polyester, polyamide, ionomer, ethylene/
Examples include, but are not limited to, vinyl acetate copolymers, acrylic esters, methacrylic esters, and mixtures thereof.

Next, a method for manufacturing the laminated film of the present invention will be explained. First, prepare a plastic film as a base material. The film may be treated with a corona discharge treatment, an acrylic resin, a urethane resin, etc., as necessary, a swellable layered silicate, a vinylidene chloride resin, or a polymer having a reactive group as described in the present invention. The layer consisting of coalescence is formed by a known method,
That is, it can be obtained by coating with a kiss coater, die coater, reverse coater, gravure coater, spray coater, bar coater, or the like. Also, when applying to stretched films such as polyester film, polypropylene, polyphenylene sulfide, etc.
After coating the film with the necessary surface treatment, stretching,
Further heat treatment is more preferable because the toughness and barrier properties of the coating film are further improved.

[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
The oxygen permeability was measured.

■Water vapor water vapor transmission rate measurement device (manufactured by Honeywell (1), W82
The water vapor transmission rate was measured at 24° C. and 1100% RH using a model 5.

The barrier properties of ■ and ■ above are judged according to the following criteria and are judged as "good".
The above is the effect of the present invention.

Transmittance of less than 20% when using vinylidene chloride resin alone: Transmittance of 20% or more 50
Transmittance of less than %: Good Transmittance of 50% or more and less than 80%: Good Transmittance of 80% or more: Impossible ■ Paint film adhesion Apply commercially available cellophane adhesive tape with length of 5 cm and width of 2.5 cm to paint film layer. A film (manufactured by Chiban ■) was pasted and peeled off in a 90° direction, and the area of the coating layer adhered to the cellophane adhesive tape was evaluated according to the following criteria.

A score of "good" or better means that the object of the present invention can be achieved.

Adhered area Judgment criteria Less than 5% Excellent 5% or more and less than 15% Good 15% or more but less than 30% Possible 30% or more Not allowed [Example] Next, 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 polyurethane resin was applied to a thickness of 0.1 μm to provide an anchor layer. A barrier layer with the following composition was applied on top of this anchor layer so that the thickness after drying was 1°0 μm.
Shita. After coating, dry at 120°C for 30 seconds, and then dry for 50'
C for 24 hours.

Barrier layer composition The following was used as the swellable layered silicate (a).

WMg2L! (S! 4010) F2W: Interlayer compound, choline chloride (Examples 1 to 5, Comparative Examples 2 to
4), Li'' (Comparative Example 5) was used.

However, the average particle size determined by the sedimentation method is 0.6 μm. As the vinylidene chloride resin (b), Fullhalon Latex Do-821.S (kenbetsu chemical (floor rack)) was used. As the reactive polymer (c), Denka Poval B-17 with a degree of saponification of 88% was used. (manufactured by Denki Kagaku Kogyo ■) was used.The mixing ratio and characteristic values of each are shown in the table.

As shown in the table, the reason why the three components (a), (b), and (c) exhibit good properties in terms of barrier properties and adhesion is that they are mixed in amounts within the scope of the present invention, and the intercalation compound is limited by the present invention. It can be seen that this is only true if the

[Effects of the Invention] The present invention provides a layer in which a mixture of a swellable layered silicate having a specific interlayer compound, a vinylidene chloride resin, and a reactive polymer are mixed in a specific range on at least one side of a plastic film. We were able to obtain the following excellent effects.

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

■Since there is no cohesive failure of the coating film due to the addition of the swellable layered silicate, it has excellent adhesion and can be used in packaging such as bags.

■Since the effect is achieved with a thin film, the transparency of the base material is hardly affected. It also reduces the generation of chlorine gas during recovery and incineration.

The thus obtained barrier film of the present invention has excellent barrier properties such as water vapor barrier properties and oxygen barrier properties, and adhesion, so it can be used in a wide range of applications that require various barrier properties. Since the effect is expressed in a thin film layer, it is particularly suitable for applications that require cost reduction.

Claims (1)

[Claims] (1) A coating layer containing a swellable layered silicate (a), a vinylidene chloride resin (b), and a polymer having one or more reactive groups (c) was provided on at least one side of the plastic film. A laminate, in which a compound having a cation-forming group and one or more reactive groups is present between the layers of the swellable layered silicate (a), and the weight ratio of (a)/(c) is 10 to 1/10, and (a)/(
A barrier film characterized in that b) is 2 to 1/100.