# US 4,134,875 A · Polyolefin film for agricultural use

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- Number: US 4,134,875 A
- Document ID: US4134875A
- Status: Granted
- Kind: A
- Application number: 05/887,939
- Filed: 1978-03-17
- Granted: 1979-01-16
- Earliest claimed: 1978-03-17
- Assignees: Alcudia Empresa Para la Industria Quimica, S.A.
- Inventors: Graciano J. Tapia
- Web page: https://patentgrep.com/patent/US4134875A

## CPC

- A01G 9/1438: {Covering materials therefor; Materials for protective coverings used for soil and plants, e.g. films, canopies, tunnels or cloches}
- C08K 3/22: of metals
- C08K 3/30: Sulfur-, selenium- or tellurium-containing compounds
- 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)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

Polyethylene or EVA copolymer film which includes up to about 15% by weight of an additive preferably a mixture of alunite - aluminum hydroxide is disclosed for particular use as a cover for agricultural purposes. The disclosed film has improved properties which provide growth of plants and/or crops by reducing thermal losses to the atmosphere and by minimizing shadow formation. The physical characteristics of the film are equal to or better than conventional films.

## Claims

### Claim 1

Polymeric composition especially well suited for agricultural use comprising from about 80% or more polyolefin and from about 1% to about 15% by weight of an additive referred to as a basic metallic sulfate and having the formula
(SO.sub.4).sub.4 M.sub.6.sup.111 . M.sub.2.sup.1 12(OH)
wherein
M.sup.1 is a monovalent metal,
M.sup.111 is a trivalent metal,
said film having low thermal transmittance properties between 7 and 14 micron wavelengths and excellent light diffusion properties.

### Claim 2 (depends on 1)

The polymeric composition as defined in claim 1 wherein said polyolefin is polyethylene or copolymers of ethylene.

### Claim 3 (depends on 1)

The polymeric composition as defined in claim 1 wherein said additive also includes aluminum hydroxide.

### Claim 4 (depends on 1)

The polymeric composition as defined in claim 1 wherein said basic metallic sulfate is alunite.

### Claim 5 (depends on 1)

The polymeric composition as defined in claim 1 wherein said additive comprises a mixture of alunite and aluminum hydroxide (or hydrated alumina) which together is present in an amount ranging from 3% to 10% by weight.

### Claim 6 (depends on 5)

The polymeric composition as defined in claim 5 wherein said polyolefin is polyethylene which is present in an amount ranging from 90% to 97% by weight.

### Claim 7 (depends on 5)

The polymeric composition as defined in claim 5 wherein said polyolefin is an ethylene-vinyl acetate copolymer which is present in an amount ranging from 90% to 97% by weight.

### Claim 8 (depends on 3)

The polymeric composition as defined in claim 3 wherein the ratio of basic metallic sulfate and aluminum hydroxide ranges from about 4:1 to about 1:4.

### Claim 9 (depends on 1)

The polymeric composition as defined in claim 1 formed as film or sheet material.

### Claim 10 (depends on 3)

The polymeric composition as defined in claim 3 formed as a film or sheet material.

### Claim 11

Polymeric film for covering plants or crops comprising polyethylene or copolymers thereof with an effective amount of basic metallic sulfate having the formula:
(SO.sub.4).sub.4 M.sub.6.sup.111 M.sub.2.sup.1 12(OH)
wherein
M.sup.1 is a monovalent metal,
M.sup.111 is a trivalent metal, for imparting to said film low thermal transmittance properties between 7 and 14 microns and excellent light diffusion properties.

### Claim 12 (depends on 11)

The polymeric film of claim 11 further including aluminum hydroxide admixed with said basic metallic sulfate, said combined additive being present in an amount up to 20% by weight of said film.

### Claim 13 (depends on 3)

A composition according to claim 3 further including from about 0.05 to about 2% by weight of an ultra-violet absorber such as benzophenone or benzotriazole.

### Claim 14 (depends on 12)

A polymeric film according to claim 12 further including from about 0.05 to about 2% by weight of an ultra-violet absorber such as benzophenone or benzotriazole.