JP2843057B2 - Vinylidene chloride resin aqueous emulsion composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aqueous emulsion composition of vinylidene chloride resin which provides a film having excellent gas (particularly oxygen and water vapor) barrier properties, and excellent transparency and blocking resistance. .

This composition is used for forming a gas barrier film on the surface of plastic packaging materials such as wiener sausage, tobacco, and snacks and paper, or for forming a waterproof film on the floor of a concrete building or on a veranda. Used.

(Prior art)

The surface of a hose mainly made of regenerated cellulose used for packaging processed meat products such as sausages is coated with a vinylidene chloride resin-based aqueous emulsion and dried to form a film having excellent gas barrier properties and transparency. (Japanese Patent Application Laid-Open Nos. 51-119084 and 51-119085)
No., Japanese Patent Publication No. 49-6808, No. 52-16490, No. 60-53055
No., FP1254025). In addition, mayonnaise containers in which a polyvinylidene chloride film is formed on the surface of a polyethylene hollow container, and polyvinylidene chloride films formed on the surface of a polypropylene film or polyester film as a packaging film for tobacco or food (Japanese Patent Publication No. 47−43628
No. 49-18632, No. 51-8991, and No. 60-8254) are also known.

The first function required for a film obtained from a vinylidene chloride resin-based aqueous emulsion (aqueous dispersion) in this application is gas barrier properties, and the second is transparency. In addition, it is required to have functions such as adhesiveness to a substrate surface to which the aqueous emulsion is applied, printability to a film surface, coating properties, anti-blocking properties, and slip properties.

The gas barrier property is required to protect the quality and spoilage of food from oxygen and water vapor, and the transparency is required because the food in the film bag or the container needs to be clearly visible from the outside.

The gas barrier property and blocking resistance of the vinylidene chloride-based resin film depend on the crystallinity of the vinylidene chloride-based resin, and generally, the higher the content ratio of vinylidene chloride in the resin, the better. However, if the vinylidene chloride content is too high, the storage stability and film-forming ability of the aqueous emulsion of the vinylidene chloride-based resin obtained by emulsion polymerization decrease,
In general, commercially available products have a vinylidene chloride content of 78 to 96% by weight in the resin, and most have a content of 86 to 94% by weight. No. 60-8254) or a blend of a resin emulsion with a high vinylidene chloride content and a resin emulsion with a normal content (Japanese Patent Publication Nos. 60-45648 and 62-59724).
By doing so, compatibility with storage stability is achieved.

However, these latter highly crystalline aqueous emulsions are complicated to manufacture and costly. In order to increase the crystallinity of the vinylidene chloride copolymer, the monomers to be copolymerized are limited to those having a small molecular weight such as acrylonitrile, methyl methacrylate and acrylamide.

Further, in the case of a vinylidene chloride-based resin aqueous emulsion having a normal vinylidene chloride content, after being applied on a film or a container, the emulsion is heated and forcibly dried, and furthermore, 40 to 120 to promote crystallization of the film. Aging treatment is generally performed at a temperature of ℃, and the film is required to have anti-blocking and slipping properties for storage of the rolled-up film, supply / discharge of the film, or storage of the dried container. .

[Problems to be solved by the invention]

It has been proposed to incorporate 0.01 to 0.1% by weight of silica powder into an aqueous emulsion of vinylidene chloride-based resin in order to improve the blocking resistance and slipping property of a film formed from the aqueous emulsion of vinylidene chloride-based resin.
However, in many cases, it is difficult to uniformly mix and disperse the silica powder in the emulsion, and there is a disadvantage that the transparency of the film tends to decrease.

An object of the present invention is to provide a vinylidene chloride-based resin aqueous emulsion composition which does not cause a decrease in transparency or is extremely small and which gives a film having excellent blocking resistance, slipping property and gas barrier property. And

[Specific means to solve the problem]

In order to achieve the object, in the present invention, 0.05 to 0.8 wt. Of a non-film-forming microresin aqueous emulsion (B) is added to the vinylidene chloride resin aqueous emulsion (A) for forming a film matrix in place of silica powder. %, Almost no decrease in transparency and gas barrier property is observed even when compared with a film obtained from the vinylidene chloride resin aqueous emulsion (A) alone, and the presence of micro-particles existing in the surface layer of the film. The emulsion (B) particles made it possible to improve the slipping and blocking resistance of the coating.

That is, the present invention relates to a vinylidene chloride resin aqueous emulsion (A) having an average particle size of 0.05 to 0.3 micron and a resin aqueous emulsion (B) having a glass transition point of 50 to 150 ° C and an average particle size of 0.01 to 0.06 micron. Is an aqueous emulsion composition of vinylidene chloride resin, wherein the resin solid content of the emulsion (B) is blended in a ratio of 0.05 to 0.8% by weight based on the resin solid content of the emulsion (A).
The average particle size of the emulsion resin of (B) is smaller than the average particle size of the emulsion resin of (A). ] Is provided.

Emulsion of component (A) The aqueous emulsion of vinylidene chloride resin as component (A) can be formed into a film at room temperature, and has an average particle diameter of resin particles of 0.05 to 0.3 microns. For example, when the emulsion is 78 to 96% by weight of vinylidene, a vinyl monomer mixture with 22 to 4% by weight of another vinyl monomer is dissolved in water in which an anionic emulsifier and / or a nonionic emulsifier is dissolved. It is obtained by emulsion polymerization at 40 to 65 ° C. using a water-soluble catalyst such as a sulfate. The emulsion polymerization may be a normal one-stage polymerization or a seed polymerization method as described in JP-B-60-8254.

Other vinyl monomers include, for example, vinyl chloride, alkyl acrylate, alkyl methacrylate, acrylonitrile, methacrylonitrile, vinyl ester (eg, vinyl acetate, vinyl propionate, etc.), vinyl ether (eg, vinyl methyl ether, vinyl Ethyl ether, etc.), acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, salts of each of these acids such as sodium, potassium, ammonium, etc., further acrylamide, methacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, N-methylol acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol methacrylamide, N-ethanol methacrylamide, N-methyl Olemaleimide, N-methylolmaleamide, N-methylolmaleamic acid, N-methylolmaleamic acid ester, N-alkylolamide of aromatic vinyl carboxylic acid, methylol-p-vinylbenzamide, N-methoxymethylmethacrylamide, N-methoxymethyl methacrylamide, N-
Isopropoxymethyl acrylamide, N-isopropoxymethyl methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide, N
-Isobutoxymethylacrylamide, N-isobutoxymethylmethacrylamide and the like.

Further, as the nonionic emulsifier, there is polyoxyethylene alkyl allyl ether. As a typical example, polyoxyethylene nonyl phenyl ether having a polyoxyethylene oxide added mole number of 9 to 40 moles is preferable.

Examples of the anionic emulsifier include sulfates of higher aliphatic alcohols such as sodium lauryl sulfate, and other dialkyl sulfosuccinates.

The aqueous microresin emulsion of the component (B) has a glass transition point (Tg) of + 50 ° C. or more and an average particle size of the resin of 0.01 to 0.06 μm. It is important that the resin particle size of the microemulsion is smaller than the resin particle size of the emulsion (A) in view of the transparency of the obtained film. Further, the Tg of the resin particles must be as high as 50 ° C. or more from the viewpoint of the blocking resistance of the film.

Unlike anti-blocking agents such as conventional silica powder,
It is easy to mix and disperse and has good miscibility with the resin of the component (A) of the film matrix, so that there is no gloss of the film and no decrease in transparency.

The aqueous resin emulsion of the component (B) serves as an island of the film obtained from the composition or is present on the surface of the film to impart blocking or slipping properties to the film. When the resin particles having a large particle size form a continuous film, the micro resin particles of the component (B) do not enter the gaps between the resin particles of the component (A) and do not lower the transparency of the film. Therefore, it has a kind of resin filler function.

This micro-resin aqueous emulsion contains acrylic acid,
-COOH, -OH, such as itaconic acid, acrylamide, hydroxyethyl methacrylate, and glycidyl acrylate;
−CONH ₂ , When 0.3 to 5% by weight of a vinyl monomer having a polar group represented by the formula (1) is used as a vinyl monomer component for emulsion polymerization, the printability of a coating film may be affected.

The composition of the vinyl monomer to be emulsion-polymerized is as follows.

(A) 55-100% by weight of a hard vinyl monomer selected from vinyl acetate, ethyl methacrylate, vinyl chloride, n-propyl methacrylate, styrene, α-methylstyrene, acrylonitrile, methyl methacrylate, etc. 2-ethylhexyl acrylate, n-acrylate
-Butyl, ethyl acrylate, isopropyl acrylate, 2-ethylhexyl methacrylate, n-acrylate
Propyl, n-butyl methacrylate, vinylidene chloride,
0-40% by weight of soft vinyl monomer selected from ethylene, butadiene, etc. (c) Other vinyl monomers 0-10% by weight.

Other vinyl monomers include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic anhydride; crotonic acid, vinylsulfonic acid, monomethacryloxyethyl phosphate, and hydroxy. Examples include monomers having a functional group such as ethyl acrylate, hydroxypropyl acrylate, acrylamide, methacrylamide, methylolated acrylamide, and fumalmaleimide.

The hard vinyl monomer of (a) is a vinyl polymer whose homopolymer has a glass transition point of more than 30 ° C.
The soft vinyl monomer (b) is a monomer having a glass transition point of a homo (homo) polymer of the vinyl monomer of 20 ° C. or lower.

The selection and use amount of these monomers are selected so as to obtain the glass transition point of the target resin.

This aqueous microresin emulsion (B) can be obtained, for example, by emulsion polymerization of a vinyl monomer by the method described in JP-B-62-28187. The polymerization is carried out by first adding 30-50% of water with 20-50% of anionic emulsifier, 10-50% of nonionic emulsifier, and pre-emulsion from vinyl monomer, remaining water and remaining emulsifier Prepared separately, and the preliminary emulsion is prepared for 50 to 3 hours.
This is conveniently done by adding to the solution heated to 90 ° C. The reaction mixture is stirred and the initiator is added in the form of a 1-5% aqueous solution in parallel with the emulsion addition.
After the addition, the whole mixture is post-stirred at 70-90 ° C. for a further 1-3 hours. Even when the monomer mixture is added to a solution containing the entire amount of water and an emulsifier, a synthetic resin dispersion composed of extremely fine particles suitable for impregnation and priming having an osmotic action can be obtained. There are no mandatory conditions for the addition of emulsion to prepare a dispersion of fine particles.

This aqueous microresin emulsion may be a cold-crosslinkable aqueous resin emulsion, a self-heat crosslinkable type, or a non-crosslinkable type.

(Composition) The mixing ratio of the component (A) and the component (B) in the aqueous resin emulsion composition of the present invention is such that the component (B) is 0.05 to 0.8% by weight of the component (A) in terms of resin solid fraction. Mix. 0.05
Unless it is added in an amount of not less than% by weight, it is not possible to improve the blocking resistance and the slipping property of the film. Conversely, the addition of a large amount of the component (B) is not preferable because the gas barrier property of the film is reduced.

(Examples, etc.)

Next, the aqueous emulsion will be described in more detail with reference to Preparation Examples, Examples and Comparative Examples. "Part" described in these examples
And "%" are by weight unless otherwise specified.

Production Example of Vinylidene Chloride Resin Aqueous Emulsion Example 1 Vinylidene chloride 92 parts Methyl acrylate 4 parts Acrylic acid 1 part Acrylonitrile 3 parts Alkyl sulfonate soda salt 2 parts (Neurex C1) Potassium persulfate 0.3 part The resulting emulsion was subjected to emulsion polymerization at 50 ° C. for 30 hours, and 6 parts of polyoxyethylene nonylphenyl ether was added to the aqueous emulsion of vinylidene chloride resin to obtain about 50% aqueous emulsion of vinylidene chloride resin.

The minimum film formation temperature of this is 16 ° C and the average resin particle size is 0.1
μm.

Example 2 91 parts of vinylidene chloride, 8 parts of methyl methacrylate,
0.5 parts of itaconic acid, N-methylolacrylamide
A 0.5 part vinyl monomer mixture was emulsion polymerized in the same manner as in Example 1 to obtain a vinylidene chloride resin aqueous emulsion having a film forming temperature of 18 ° C. and a resin particle size of about 0.08 μm.

Production Example of Microresin Aqueous Emulsion Example 3 The following raw materials were charged into a reaction vessel equipped with a temperature controller, an anchor stirrer, a reflux condenser, a supply vessel, a thermometer, and a nitrogen inlet tube.

Water 275 parts 35% aqueous solution of laurylsulfonic acid sodium salt (anionic emulsifier) 25 parts 20% solution of p-nonylphenol (nonionic emulsifier) reacted with 25 moles of ethylene oxide 10 parts The following mixture was used as feed I: Using.

Water 200 parts 35% solution of the anionic emulsifier 25 parts Styrene 25 parts Methyl methacrylate 312 parts N-butyl acrylate 52 parts Acrylamide 5 parts As feed II, prepare a solution of 2.5 parts of potassium persulfate in 85 parts of water. did.

After purging the reactor with nitrogen gas, 10% of feed I was added to the charge and the mixture was heated to 90 ° C. Then 10% of Feed II is injected into the reactor, and then 3
The remaining feeds I and II were fed to the reactor over 3.5 hours. After supplying, keep at 90 ° C for 1.5 hours,
The reactor was cooled to room temperature. The pH of the dispersion was adjusted to 6 to 7.5 with aqueous ammonia to obtain an aqueous microresin emulsion having a solid content of 40% by weight, a Tg of 71.5 ° C. and an average particle size of 0.03 μm.

Examples 4 to 6 A microresin aqueous emulsion shown in Table 3 was obtained in the same manner as in Example 3 except that the kind and composition of the vinyl monomer were changed as shown in Table 1.

Silica powder Mizusawa Chemical Co., Ltd. Fine powder silica "P-801" average particle size
2.8 ± 0.5 (catalog value) was used.

 Resin particle size: by electron microscopy.

Minimum film formation temperature: Japan Emulsion Industry Association measurement method, synthetic resin emulsion test method JEI 101-1988 Glass transition point: By differential analysis.

Instrument name Differential thermal analyzer manufactured by DuPont Measurement conditions Heating rate: 10 ° C./min Examples 1 to 6, Comparative examples 1 to 8 Table 2 shows the aqueous resin emulsion and silica powder of Examples 1 to 6.
To obtain various coating water-based resin emulsion compositions (coating compositions).

Each of the obtained coating compositions was tested for physical properties of the coating film by the following method. The results were as shown in Table 2.

(1) Blocking resistance A dispersion is applied to a biaxially stretched polypropylene film having a thickness of 60 µm (Yuika Sansho Co., Ltd.) so that the dry coating amount is 5 g / m ² , and dried at 100 ° C for 2 minutes. after, then 30 seconds aging treatment at 100 ° C., overlapping the applied surface each other of the resulting film, after 24 hours at a temperature of applying a load of 250g / cm ² 40 ℃, the tackiness of the coated surface It was examined and evaluated as follows.

A: The coated surfaces peel off without any resistance.

B: After rubbing lightly with your fingertips a few times, peel off with Sarari.

C: There is some resistance, but it is peeled off without damaging the coated surface.

D: There is resistance when peeled off, and the coated surface is scratched.

(2) Slip property The coated surfaces of the coated and dried films obtained in (1) were overlapped, pressed with a finger, and examined for slipperiness, and evaluated as follows.

A: I slip without any resistance.

B: Slip with almost no resistance.

C: Slip but slight resistance.

D: There is considerable resistance and it is hard to slip.

(3) Heat-resistant water whitening property A 15μ thick polyamide film (manufactured by Unitika)
The dispersion was applied so that the amount of the dried coating film was 5 g / m ² , dried at 100 ° C. for 3 minutes, immersed in hot water of 95 ° C. for 30 minutes, and examined for the degree of whitening deterioration of the film taken out. It evaluated as follows.

A: Transparent B: Light blue color C: Blueish color D: Whitening (4) Oxygen barrier property The coated film obtained in (1) is further 100%.
After aging treatment at a temperature of 30 ° C., the oxygen barrier property was measured at 20 ° C. and 100% relative humidity (RH) using an oxygen permeability measuring device (OX-Tran 100, manufactured by MoCoN).

 The unit of the evaluation value is as follows.

cc / m ² .24 hr. 20 ° C. 100% RH (5) Haze (JIS K6717) The haze (haze degree) was measured on 10 sheets of the biaxially stretched polypropylene coated film obtained in (1). .

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 27/08 C09D 127/08

Claims (1)

(57) [Claims] An aqueous emulsion of vinylidene chloride resin (A) having an average particle size of 0.05 to 0.3 micron is mixed with an aqueous resin emulsion (B) having a glass transition point of 50 to 150 ° C. and an average particle size of 0.01 to 0.06 micron. A vinylidene chloride-based resin aqueous emulsion composition which is blended in such a manner that the resin solid content of the emulsion (B) is 0.05 to 0.8% by weight based on the resin solid content of the emulsion (A). [However, the average particle size of the resin of the emulsion (B) is
It is smaller than the average particle size of the resin of the emulsion (A). ]