JPS6047292B2 - Resin solution for film surface treatment and film surface treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin solution for surface treatment of polyvinyl alcohol films and a method for surface treatment of films using the resin solution.

Polyvinyl alcohol (hereinafter abbreviated as PVA) film has transparency, surface gloss, printability, poor mechanical strength, and is non-static, so it is widely used as a packaging material for textile products. .

However, the physical properties of the PVA film change sensitively due to changes in temperature and humidity, and blocking occurs easily when the film surfaces are brought into contact with each other under high temperature and humidity. For this reason, when making high-speed bags using an automatic bag making machine, there are drawbacks such as difficulty in feeding the film or adhesion to the equipment, and in bagging work for textile products, it may be difficult to open the opening. Since this impairs the properties of the PVA film, a method is used in which a finely powdered inorganic substance is sprayed onto the surface of the PVA film. However, although this method is effective in preventing blocking,
It reduces the transparency of the film, and when the powder falls off and adheres to textile products, especially products dyed in deep colors, it significantly impairs the commercial value. In addition, an organic solvent solution of a polymer substance is
There is also a known method of coating PVA-based films to prevent blocking, but the polymeric substances used in this method are usually hydrophobic and have poor adhesion to PVA-based films, so when heat-sealing, The coating layer and the PVA film layer are likely to peel off. Furthermore, there is a method of coating a PVA film with an adhesive consisting of a water-methanol solution of zinc chloride, lithium chloride, etc., but this method significantly reduces adhesive properties during adhesion and is not practical. The present invention aims to solve these drawbacks, and is made by dissolving a methanol-soluble vinyl acetate resin containing 50% or more of vinyl acetate (hereinafter referred to as vinyl acetate resin 5) and a styrene resin. By dispersing the inorganic fine powder in a solution, applying it to the surface of the PVA film and drying it, it has excellent transparency and bag-making properties (heat-sealing properties and sizing properties using adhesive), and there is no powder falling off. Moreover, the PV is non-blocking.
Some companies are trying to provide A-type films.

That is, the first invention has an average particle diameter of 5 to 1000 rT.
Methanol-soluble vinyl acetate in which 1μ inorganic fine powder is dispersed Contains 50% by weight or more of vinyl acetate resin and styrene resin as main components, and the component ratio is 25/75 to 75/25 by weight. There is a polyvinyl alcohol-based film surface treatment resin solution, and the second invention is a methanol-soluble vinyl acetate resin solution containing at least 4% by weight of methanol-soluble vinyl acetate in which inorganic fine powder with an average particle size of 5 to 1000 rT1p is dispersed, and styrene. Contains a system resin as a main component, and the component ratio is 25/75 to 75 by weight.
A polyvinyl alcohol-based film characterized by applying the polyvinyl alcohol-based film surface treatment resin solution No. 25 so that the amount of inorganic fine powder becomes 0.05 to 0.5 g/d per one side of the polyvinyl alcohol-based film and drying it. This is a film surface treatment method.

In terms of transparency, the refractive index of these polymeric materials is higher than that of PV
It is desirable to select one that is similar to that of the A-based film. Styrenic resins have excellent transparency and surface gloss, and have a moderate anti-blocking effect, but their heat-sealing properties and pasting properties using PVA-based film adhesives are insufficient.

Water/methanol solutions of zinc chloride, lithium chloride, etc. are widely used as adhesives for PVA films.

These PVA-based film adhesives have adhesive properties,
As a result of extensive research into substances that are compatible with styrene resins and have affinity with PVA films, it has been found that methanol-soluble vinyl acetate resins are suitable for this purpose. The styrene resin used in the present invention is preferably polystyrene, styrene-methyl methacrylate copolymer, or styrene-acrylonitrile copolymer, but any of these may be used as long as it has anti-blocking properties for PVA films without impairing transparency. Don't worry about it. Vinyl acetate resin is
It is sufficient that the vinyl acetate content is 50% by weight or more, and polyvinyl acetate, bevy-acetic acid crotonic acid copolymer, bevy-acetic acid acrylic acid copolymer or bevy-acetic acid itaconic acid copolymer is preferable, and the adhesive properties of the PVA film are excellent. Other copolymerized components may also be used.
Methanol-soluble vinyl acetate resin, styrene resin and/or
Or the component ratio of methacrylic resin is 25/75 to 25/75 by weight.
A range of 75/25 is preferred. If the component ratio is less than 25/75, the adhesiveness of the PVA film adhesive will be insufficient, and if it exceeds 75/25, the anti-blocking effect will be adversely affected. A methanol-soluble vinyl acetate resin, a styrene resin, and/or a methacrylic resin are dissolved in these common solvents.

The common solvent is appropriately selected from, for example, esters, aromatics, chlorine-based solvents, and the like. The concentration of dissolved resin varies depending on the coating layer thickness, texture, and workability, but it is 0.
．． 5 to 10% is preferably used.

The above coating composition alone can exhibit a sufficient anti-blocking effect depending on the conditions of use, but in order to withstand practical use under high temperature and high humidity, it is necessary to add an inorganic fine powder.

As the inorganic fine powder, for example, silicic anhydride, silicates, talc, kaolin, alumina, calcium carbonate, magnesium carbonate, etc. are used, but in order not to impair transparency, the average particle size should be 5 to 1000111μ. There are certain things that need to be done.

Further, the coating amount is preferably 0.05 to 0.5 g/d per side. If it is less than 0.05 g/I (per side), sufficient blocking prevention effect will not be produced, and 0.5
If the amount exceeds g/d (per side), the transparency will be significantly reduced.

The coating amount of the resin component is preferably 0.1 to 1.0 g/d;
．． If it is less than 1 g/bo, the anti-blocking effect will not be sufficient, and if it exceeds 1.0 g/bo, the transparency will be significantly reduced. In addition, the inorganic fine powder is made of resin (methanol-soluble vinegar/vinyl acetate resin, styrene resin, and/or methacrylic resin).
It is desirable that the amount of saliva does not exceed 10%. When the amount exceeds 10%, powder tends to fall off.

Methanol-soluble vinyl acetate resin, styrene resin and/or
Alternatively, fine inorganic powder is added to a solution of methacrylic resin in an organic solvent and sufficiently dispersed by stirring. To apply the coating composition prepared in this manner onto a PVA film, a device such as a dip coater, a gravure coater, a reverse roll coater, or the like is used, for example. It is also possible to adopt a spray method. The PVA film surface-treated according to the present invention does not impair its transparency, surface gloss, pasting properties, or heat sealability, and has a stable blocking prevention effect. Since there is no contamination, it is useful as a material for textile packaging.

The present invention will be explained in more detail below with reference to Examples.

Note that all parts described in the specification are expressed on a weight basis.
J Example 1 2 parts of polystyrene resin and 1 part of vinyl acetate resin (trade name: vinyl acetate homopolymer) manufactured by Denki Kagaku Kogyo Co., Ltd. were dissolved in a mixed solution of 7 parts of ethyl acetate and 9 parts of toluene. ), anhydrous silica, -Product name: RAER
OSIL-130! 0.5 part of a material having an average diameter of 16 mp was added and stirred to disperse.

The coating composition thus prepared was coated with a dip coater to a thickness of 0.03T0n1 with an average degree of polymerization of 160.
The coated film was coated on both sides of a polyvinyl alcohol film with a saponification degree of 99.5 mol% and dried at a temperature of 80°C to obtain a coated film with a coating amount of 0.7 g/d per side. The quality evaluation results of the coated film are shown in the table. The surface treated film according to Example 1 has transparency, anti-sticking properties,
Both adhesive properties and heat sealability were excellent. Example 2 Styrene-methyl methacrylate copolymer (40% by weight of styrene, 6% by weight of methyl methacrylate) 1 part, vinyl acetate copolymer resin manufactured by Denki Kagaku Kogyo Co., Ltd. Trade name 1 Denka ASRCH-
Dissolve 1 part of crotonic acid (crotonic acid 5% by weight) in 10% of ethyl acetate and prepare the product under the trade name RAERO manufactured by Nippon Aerodino Uso (Ten).
Add 1 part of SIL-300J (anhydrous silica, average diameter 7 mμ) and stir to disperse.

This solution was coated with a gravure coater to a thickness of 0.04 mm.
The coating was applied to both sides of a polyvinyl alcohol film having an average degree of polymerization of 17000 and a degree of saponification of 99.9 mol %, and dried at 80° C. to obtain a coated film with a coating amount of 0.4 g/d per side. As shown in the table, this film has transparency,
Excellent anti-sticking properties, adhesive properties, and heat seal properties. Example 3 1 part of styrene-acrylonitrile copolymer (75% by weight of styrene, 25% by weight of acrylonitrile), manufactured by Denki Kagaku Kogyo Co., Ltd., vinyl acetate copolymer resin trade name 7 Denka ASRC
2 parts of L-13 (7.% crotonic acid) was dissolved in 100 parts of ethyl acetate, and 1 part of talc was added, stirred, and dispersed.

Spread this solution to a thickness of 0.03? With a spray gun, a coating amount of 0.6 g/Rr was applied to both sides of a polyvinyl alcohol film with an average degree of polymerization of 1600 and a degree of saponification of 99.8 mol%.
1 (per one side). This film is
As shown in the table, it showed excellent properties as a fiber packaging material. Comparative Example 1 Example 1
When the same procedure as in Example 1 was carried out except for the following, as shown in the table, the adhesive properties were significantly deteriorated.

Comparative Example 2 The same procedure as in Example 2 was carried out except that 0.5 part of styrene-methyl methacrylate copolymer and 2 parts of 1Denka ASRCH-9j were used in Example 2. As shown in the table,
The blocking prevention effect was insufficient.

The physical properties of the Examples were measured and evaluated using the following methods.

(1) Transparency: Two layers of film are transparent.
Compare the quality and gloss.

A: Transparency and gloss due to coating
There is almost no decrease in

5B: Y) It's cloudy, but there's no problem.

C: Cloudiness and a significant decrease in transparency.

(2) Anti-blocking property: Film 10cm x 15
Cut into cm pieces and heat at 25°C-75%R. H. 24 in the atmosphere of
After leaving for a while, stack 20 sheets, apply a 200g load evenly, and leave for another 24 hours.

Then, the load is removed and the
Mutual peeling of film
Compare the properties and slipperiness. A: Good releasability and slipperiness.
B: Y) It's a little close contact, but there's no problem.

C: Adhesion, practical problems.

(3) Sizing properties: Zinc chloride 5% by weight, water 15% by weight, Me! Evaluation was made using an adhesive containing 35% by weight of tanol.
Ru.

Cut the film into 2cm x 10cm and cut one end
Put one drop of the above adhesive on the film, overlap one end of another film of the same size, press it lightly with your fingers, and then pull both ends of the glued film.

A: Good adhesion, cutting from other than the adhesive part.

B: Poor adhesion (adhesion), adhesive strength is good, but it peels off from the adhesive part.

C: Poor adhesion, easily peeled off from the adhesive part.

Heat sealability: Adhesiveness was compared using a bar sealer at 340°C and 0°C.

A: Sufficiently heat sealed.

B: Adhesive but easily peeled off.

C: No adhesion at all.

Claims (1)

[Scope of Claims] 1 Methanol-soluble vinyl acetate in which inorganic fine powder with an average particle size of 5 to 1000 mμ is dispersed Contains 50% by weight or more of a vinyl acetate resin and a styrene resin as main components, and furthermore, the component ratio The weight ratio is 25/75 to 75/2
5, a polyvinyl alcohol-based film surface treatment resin solution. 2 Methanol-soluble vinyl acetate in which inorganic fine powder with an average particle size of 5 to 1000 mμ is dispersed Contains 50% by weight or more of vinyl acetate resin and styrene resin as main components, and the component ratio is 25/2 by weight. 75-75-2
A polyvinyl alcohol film characterized by applying the resin solution for surface treatment of polyvinyl alcohol film according to No. 5 so that the amount of inorganic fine powder is 0.05 to 0.5 g/m^2 per one side of the polyvinyl alcohol film and drying it. Surface treatment method for alcohol-based films.