The Nippon Synthetic Chemical Industry Co., Ltd.

Mebiol Inc.

Tomoyoshi Mizutani

Hiroshi Yoshioka

Yuichi Mori

Mitsuhiro Hasegawa

Akihiro Okamoto

Syuichi Kitamura

Hideki Oono

Shigeki Miura

Kenji Hasegawa

Shuichi Kitamura

Manabu Miyato

Prior art technology has a problem in that when a plant is cultivated for a long period of time on a PVA film having its lower surface positioned in contact with a nutrient fluid, plant roots that have formed penetrate through the film. A plant cultivation system wherein the PVA film has an equilibrium degree of swelling in the range of from 125 to 250% as measured in water at 30&#xb0; C. and has a loss tangent (tan &#x3b4;) in the range of from 0.005 to 0.2 as measured in an equilibrium swollen state in water at 30&#xb0; C., and a method for cultivating a plant by using this plant cultivation system. Plant cultivation can be performed for a long period of time while avoiding infection by bacteria and the like causative of plant diseases. Therefore, the present invention is useful in, e.g., agriculture and the manufacture of pharmaceuticals.

Plant cultivation system and a method for plant cultivation

The present invention relates to a water-soluble film, which is a polyvinyl alcohol film comprising a polyvinyl alcohol resin (A), wherein the water-soluble film has a time for dissolution in water at 20&#xb0; C. of not more than 60 seconds in terms of a film thickness of 76 &#x3bc;m, a b-value of the film is not more than 0.5, and a b-value of the film after leaving at 80&#xb0; C. for 72 hr is not more than 1.0, preferably a water-soluble film comprising: a polyvinyl alcohol resin (A); at least two kinds of plasticizers (B); and a sulfite salt (C), wherein the content of the plasticizer (B) based on 100 parts by weight of the polyvinyl alcohol resin (A) is 5 to 50 parts by weight and the content ratio of the sulfite salt (C) to the plasticizer (B) (C/B: weight ratio) is more than 0.02 and not more than 0.35. According to the invention, there is provided a water-soluble film comprising a PVA resin as a main component, wherein the film is less likely to cause coloration at the time of film formation and coloration with time even upon contact with a chemical.

Water-soluble film

A water-soluble film made from a resin composition comprising (A) 100 parts by weight of an anionic group-modified polyvinyl alcohol having a viscosity of 10 to 35 mPa&#xb7;s measured at 20&#xb0; C. with respect to a 4% by weight aqueous solution thereof, an average degree of hydrolysis of 80.0 to 99.9% by mole and a rate of anionic group modification of 1 to 10% by mole, (B) 20 to 50 parts by weight of a plasticizer, (C) 2 to 30 parts by weight of a filler, and (D) 0.01 to 2.5 parts by weight of a surfactant. The water-soluble film has an excellent water solubility, and is not gelled or insolubilized even if chemicals containing a boric acid substance, particularly sodium perborate, are packaged therein or even if it is put in an aqueous solution of a boric acid substance, particularly sodium perborate.

Water-soluble film of polyvinyl alcohol

A method for producing an embossed PVA film, which includes embossing the film such that the crystallinity index of the emboss top is 0.50-0.90. The invention provides an embossed PVA film superior in resistance to blocking even when in a rolled state, in appearance to show the high quality of products, and in resistance to pinholes.

Method for producing embossed poly(vinyl alcohol) film

The present invention provides a film for packaging chemical agents, which contains an oxyalkylene unit-containing polyvinyl alcohol resin (A) and a carboxyl-containing polyvinyl alcohol resin (B), and preferably further containing a sulfo-containing polyvinyl alcohol resin (C). This film shows fine solubility in water even after a long-term packaging of an acidic chemical agent or alkaline chemical agent, and is superior in mechanical strength. Thus, the film for packaging chemical agents of the present invention is suitably used for packaging a chemical agent, such as powdered soap, synthetic detergent, agricultural chemical, antibacterial, deodorant, insecticide and the like, which is cast into water when in use.

Growing community of inventors

Osaka, Japan

Tomoyoshi Mizutani