# US 2014/0150338 A1 · Film for plant cultivation

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- Number: US 2014/0150338 A1
- Document ID: US20140150338A1
- Status: Published application
- Kind: A1
- Application number: 13/820,906
- Filed: 2011-09-09
- Published: 2014-06-05
- Earliest claimed: 2010-09-28
- Inventors: Masahiro Takafuji; Takanori Isozaki
- Web page: https://patentgrep.com/patent/US20140150338A1

## CPC

- A01G 22/00: Cultivation of specific crops or plants not otherwise provided for
- A01G 9/1438: {Covering materials therefor; Materials for protective coverings used for soil and plants, e.g. films, canopies, tunnels or cloches}
- B29C 55/04: uniaxial, e.g. oblique
- B29D 7/01: Films or sheets
- C08J 5/18: Manufacture of films or sheets
- B29K 2029/04: {PVOH, i.e. polyvinyl alcohol (B29K2031/04 takes precedence)}
- B29K 2995/0034: Polarising
- C08J 2329/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
- Y02A 40/25: Greenhouse technology, e.g. cooling systems therefor
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

[Task] The objects of the present invention are to provide: a polyvinyl alcohol (PVA) film for plant cultivation which is capable of suppressing root penetration while exhibiting excellent nutrient permeability; a method for producing the same; and a method for plant cultivation using the same. [Means to Achieve the Task] The present invention is directed to a PVA film for plant cultivation, wherein a thicknesswise-directional average value of birefringence in a machine direction of the film is from 4.0×10−3 to 12.0×10−3 and a swelling degree of the film is from 150 to 180%; a method for producing a PVA film for plant cultivation, which comprises a step in which a PVA film having a moisture content of from 5 to 20% by mass is stretched in the ratio of from 1.3 to 1.7 times and a step in which the stretched film is heat-treated at a temperature in the range of from 130 to 170° C.; and a method for plant cultivation, which comprises cultivating the plant in the manner in which the plant and the PVA film for plant cultivation described above are directly contacted.

## Claims

### Claim 1

A polyvinyl alcohol film for plant cultivation, wherein a thicknesswise-directional average value of birefringence in a machine direction of the film is from 4.0×10−3 to 12.0×10−3 and a swelling degree of the film is from 150 to 180%.

### Claim 2 (depends on 1)

The polyvinyl alcohol film for plant cultivation according to claim 1, wherein a penetration resistance of the film is 15.0 N or more in terms of a maximum load measured by a method comprising immersing the film in water at 20° C. for 1 minute and then piercing the film with a thick iron wire nail (CN65) defined in JIS A5508:2009, provided that the maximum load is a converted value exhibiting a maximum load when the thickness of the film is 60 μm.

### Claim 3

A method for producing a polyvinyl alcohol film for plant cultivation, which comprises a step in which a polyvinyl alcohol film having a moisture content of from 5 to 20% by mass is stretched in the ratio of from 1.3 to 1.7 times and a step in which the stretched film is heat-treated at a temperature in the range of from 130 to 170° C.

### Claim 4 (depends on 3)

The method according to claim 3, which further comprises, after the said step of stretching and before the said step of heat treatment, a step in which the film is dried so that the moisture content of the film becomes from 1 to 15% by mass.

### Claim 5 (depends on 1, 2)

A method for plant cultivation, which comprises cultivating the plant in the manner in which the plant and the polyvinyl alcohol film for plant cultivation according to claim 1 or 2 are directly contacted.