JPS6342861A - Agricultural film having improved heat-insulating property and drip-proofing - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a film for use in cold weather with improved heat retention properties 2 and +I resistance properties.

Conventional vocational methods and their I, J, J description> Attempts have been made to improve the heat retention and drip-proof properties of AG films, and a number of techniques have been proposed.

In order to improve heat retention, many solid particles such as silicon oxide, aluminum silicate, and talc, which have infrared water absorption ability, are added to polyolefin resins, as disclosed in L.Jikado No. 58-128858 and JP-A-6O- 2518
24i+ Publication, Special Publication No. C8 Sho 61-83243 ψl).

゛Additionally, addition of surfactants, etc. have been proposed to improve drip-proofing properties, but the present inventors have further developed a multilayer film structure in order to improve the problems of this technology, and the inner layer is made of polyolefin resin. Special application for the production of agricultural films using anti-striping agents and super absorbent resins.
-2244s) Improved drip resistance.

However, with this method, the heat retention is insufficient, that is,
Until now, there has been no agricultural film that has sufficient heat retention and drip-proof properties.

<Means for solving the problem of t8> As a result of intensive studies, the present inventors have found that the conventional problems can be solved by providing a specific heat retaining layer and drip-proof layer in a multilayer film structure made of a polyolefin resin composition. They found this and completed the present invention.

That is, the present invention has a multilayer film structure of a polyolefin resin composition, and at least one layer on the plant cultivation side and other layers as necessary are made of polyolefin resin 119100.
! The drip-proof layer contains 0.1 to 5 parts by weight of a drip-proof agent and 0.1 to 15 parts by weight of a super absorbent resin, and at least one other layer is made of polyolefin tea plant! ! ? 1
To provide an agricultural film, which is a heat retaining layer, in which 2 to 80 parts by weight of an inorganic filler having an absorption band in the infrared wavelength region of 7 to 15 μm is added and mixed to 00 parts by weight.

Since the drip-proof layer must be used on the plant cultivation side, it is desirable that this layer be colored and/or printed with characters.

The polyolefin resin used in the present invention is one that has been conventionally used as a film base material for agricultural films, and is an α-olefin homopolymer or α-olefin resin.
- It is a copolymer with an olefin-based monomer, and it is said to be a copolymer of low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, ethylene:z-
For acetic acid, 'nyl co-I polymer, ethylene-acrylic acid copolymer, ethylene-butylene copolymer, etc. can be used. Among these, ethylene-vinyl acetate comonomer is preferably used because a flexible film can be obtained at a lower cost than other 4111s.

The filler, which has a water absorption band of infrared wavelengths of 7 to 15μ, used in the present invention is usually a polyolefin-based filler.
There are no limitations as long as it is used to improve the heat retention of 1W films, and examples thereof include silicon oxide, alumina silicate, titanium silicate, phosphate, sulfate, and talc. The blending ratio of these O and Tia fillers to the polyolefin tree is as follows: It is more preferable that the amount is 2 to 30 parts by weight, and 5 to 16 parts by weight per 100 parts by weight.

If the amount of the inorganic filler is less than double talk part, the effect of improving the heat retention of the resulting film will not be very noticeable, and if the amount is 30 parts by weight, the strength of the resulting film will decrease. Undesirable.

Furthermore, the protective agent used in the present invention is one that is commonly used and is not particularly limited.
sorbitan-glycerin mixed polyol ester of hydrochloric acid having 12 to 22 carbon atoms as described in (hereinafter referred to as drip-proofing agent A), 12 to
Sorbitan esters of fatty acids having 22 carbon atoms, glycerin esters thereof, 0.5 to 5 moles of ethylene oxide or propylene oxide added thereto, or mixtures of two or more thereof are preferred. Furthermore, although the above drip-proofing agents may be used alone, they may be combined with sorbitan esters of hydroxy fatty acids having 12 to 22 carbon atoms, glycerin esters of hydroxy fatty acids having 12 to 22 carbon atoms, or adducts thereof with ethylene oxide or propylene oxide of 96 to 5 moles of KO. One or more types (hereinafter,
It is preferable to use a mixture of drip-proofing agent B) from the viewpoint of long-term waterproofing properties and blocking prevention.

The addition f11 of these drip-proof agent mixtures needs to be 0.1 to 6 parts by weight per 100 parts by weight of polyolefin resin, and if it is less than 0.1, a sufficient drip-proof effect cannot be obtained. Moreover, if the amount exceeds 6 parts by weight, it may become difficult to mix into the polyolefin resin, or the strength of the film will be significantly reduced.

Less practicality.

1&, the mixing ratio of the above-mentioned drip-proofing agent A and drip-proofing agent B is preferably A/B = 9515 to 5/95 in weight ratio, and further ^/B
-70/80 to 40/60 is more preferred.

When the mixing ratio of drip-proofing agent A and drip-proofing agent B is larger than that of A/B-95/Is, it is difficult to develop drip-proofing properties on the film surface, whereas A/B=,=5/95 If the amount of drip-proofing agent A is less than that, the drip-proofing agent will bleed out to the film surface, which is preferable.

In addition, examples of the superabsorbent resin used in the present invention include conventionally known saponified vinyl acetate-methyl acrylate copolymers, cross-linked products of modified isobutylene-maleic anhydride copolymers, and cross-linked monostructures. polyacrylic acid with (
Specific examples include, but are not limited to, starch-acrylic acid (salt) copolymers. The superabsorbent resin may be used alone or in combination of 2 or more, but especially cross-linked vinyl acetate-methyl acrylate copolymer saponified product, isobutylene-maleic anhydride copolymer modified product The body is desirable because it has excellent durability. Among these super absorbent resins, those having a water absorption 1 of 20,971 or more, particularly 100,971 or more are preferably used.

If the water absorption is less than 20 f/f, it is difficult to obtain the heat retention and water drop prevention effects that are the characteristics of the present invention.
Nine, the particle size of the superabsorbent resin needs to be small,
It is preferable that the average particle size is 80μ or less, and it is especially 1
It is more preferable that the thickness is 5μ or less. If the average particle size exceeds this range, the strength of the resulting film will be significantly reduced, which is not preferable.

In addition, the blending amount of super absorbent resin is 1 part of polyolefin resin.
0.1 to 15 parts by weight, especially 1 to 10 parts by weight
More preferably, it is a heavy part. The blending amount is 0.1]
! If the film is not moistened, the water drop prevention effect of the obtained film will not be recognized, and if the amount added exceeds 15 parts by weight,
The strength and light transmittance of the resulting film are reduced.

The production of the agricultural film of the present invention will be illustrated.

In advance, (υ polyolefin base [11K), the above-mentioned inorganic filler is wetted and mixed to form pellets.

(2) Mix a drip-proofing agent and a super absorbent resin with a polyolefin resin to make a nine-peleft.

The method for producing pellets in (1) and (2) is to produce pellet-like tcJ by a normal method such as mixing or a-freezing in a roll-type or Banbury-type mixer or extruder.
I can build it.

Next, using the pellets (1) and (2) obtained above, a method of forming a stone horizontal shoulder film by dry lamination, heat lamination, etc., which is usually used in the production of films for the A industry, and extrusion. It is possible to form a composite film by using existing techniques such as a method of molding, a method of simultaneously molding a laminated film by a multilayer extrusion method, etc. In particular, a method of forming a film by a multilayer extrusion method is easy to mold and has advantages. In addition, a wide film is preferable for industrial applications, so the multilayer inflation film processing method is preferable.

In the multilayer film structure of the present invention, the same type of resin may be used for each layer, or different types of resin may be used for each layer.

For example, to strengthen the stiffness of a film, a homopolymer of low-density polyethylene is used in a certain layer, and others +41 (
Safe! J11 and drip-proof 1) are preferably made of copolymer type polyethylene.

Further, when the tear strength of the film is required, ethylene-vinyl acetate copolymers of the same liter each are preferred.

Further, the thickness of each layer is determined depending on the final use and the like, and is not necessarily specified.

In addition, in order to prevent a decrease in internal and external haze, the particle size of the inorganic filler and super absorbent resin used in the heat retaining layer and drip-proof footwear is preferably small, such as #1, and usually about 1 to 80 microns.

In each layer, appropriate stabilizers (thermal stabilizers, oxidation stabilizers, light stabilizers, etc.), inorganic fillers (other than those used in the present invention, such as calcium carbonate, clay, etc.), mold agents, etc. are added as necessary for each layer. It is also effective to appropriately mix antifogging agents, antifogging agents, plasticizers, colorants, and the like.

Note that film formation is usually performed at a processing temperature of 180 to 250°C, and since the inorganic filler and super absorbent resin used in the present invention may release adsorbed water in this temperature range, It is preferable to use a film from which adsorbed water has been removed by drying. <Effects of the Invention> The agricultural film obtained by the method of the present invention has both heat retention and drip-proofing properties, and the drip-proofing properties of the film are comparable to those of normal films. Its effects are demonstrated over a longer period of time compared to other products.

For example, when the film of the present invention is used inside a house, it is possible to prevent water droplets formed on the surface of the house for a long period of time.

The method of the present invention relies on long-term I/C and drip-proof properties, so it is possible to prevent downy mildew, gray mold, and sclerotium from occurring in crops grown in greenhouses. can prevent the occurrence of diseases.

Furthermore, the film of the present invention has optimal heat retaining properties as an opaque film and prevents plants from burning, so it is preferable for raising seedlings of leafy vegetables such as lettuce and cabbage and paddy rice.

As described above, the method of the present invention provides an innovative film for backboards that has excellent heat retention properties, long-term drip-proof properties, and no surface bleed.

<Examples> Next, the present invention will be described with reference to Examples, but these Examples are merely illustrative, and the present invention is not limited thereto. The heat retention measurements shown in the Examples and Comparative Examples were carried out using one of the approximately 80 cm cubic boxes made of heat insulating material.
Using a heat retention measuring device with a sample on one side, the temperature change inside the device due to a 100° C. heating block inserted into the box was measured with a thermistor. Standard sample glass plate (
The temperature difference from the value indicated by approximately 2sII thickness) is defined as the heat retention property.
ΔT'C).

In addition, the drip-proofing test of the film was conducted using the following method: Fill a 100 cc beaker with water (80°C), cover it with a sample film, and then place the beaker in a constant temperature bath (80°C). The results of the evaluation of Uso, which were left in a sunny place and observed after a predetermined period of time, were expressed using the following criteria.

O: No small water droplets at all, △D Small water droplets are observed in some areas, X: Small water droplets adhere to the entire surface, Example 1 (A) Production of resin for heat insulation layer Ethylene with vinyl acetate content of 15fi411% - Vinegar and vinyl; combined (M! = 21710 minutes> to
Dried for 2 hours at 250" O with 2 parts of ox (AL208: 2 ai %, 5i02
: 6121%, NagO: 10'1ffi%, about 2
8 parts of aluminum silicate gel (AM26% by weight) and 0.2 ii fl of glycerin monostearate
Add fJs and bring the resin temperature to 1 using a 54 Banbury mixer.
After mixing for 10 minutes at 30 to 140"C, granulated pellets were produced using an extruder.
For each part of iifi, 1 part of sorbitan-glycerin mixed polyol hydroxystearate o, 7M' and 1 part of glycerin monostearate by 0.8 weight and a super absorbent resin (manufactured by Juju Chemical Co., Ltd., Sumikagel ■5P-510, average particle Add 3 parts by weight of the mixture (diameter lOμ) and use a 5L Banbury mixer to produce granulated pellets for anti-striping in the same manner as in [A]: Preparation of heat retention pellets.

[C] The vinyl acetate content of the outer end resin is 62! % of ethylene-vinyl acetate comonomer (MI = 1.5jF/10 min). (caliber 1501), the middle layer of the die is heat insulation layer pellets [A], the inner layer is drip-proof 1 pellets (''B), and the outer layer is pellets (C). Using pellets,
Under the conditions of a die temperature of 190°C, the resin supplied to each layer is laminated inside the die, and a 3 tm Santoifuchi structure tubular body is blow-up at a pressure of 2.4 degrees, a frost line distance of approximately 200-1, and a take-up speed of 4. Received under the condition of 9 ml*,
Folding diameter: 3651, thickness of each layer: inner layer (splash-proof NI) approximately 50μ,
A satin-finished film with a firm and supple feel and a three-no-sand-inch structure consisting of an intermediate layer (heat-retaining layer) of about 50 μm and an outer layer of about 20 μm was obtained.

Table 1 shows the results of measuring changes over time in the heat retention and water drop prevention properties of the obtained film. Indicated.

Example 2 In Example 1, instead of the super absorbent resin (Sumikagel ■5P-510) used for the inner layer, 4 parts by weight of KI Gel 201K (manufactured by Clarei Soprene Chemical Co., Ltd., mechanically crushed to about 10μ) was used. Example 1 was repeated except that a satin-finished film having a three-layer sand-and-edge structure and having a firm and supple feel was obtained.

In addition, changes over time in the heat retention properties and water droplet prevention properties of the obtained films were measured. The results are shown in Table 1, and the heat retention property was good, and even after 9 months, good water droplet prevention property was shown.

Example 8 A satin-finished film having a three-layer sandwich structure and having a firm and supple feel was obtained in the same manner as in Example 1, except that sorbitan sesquipalmitate was used instead of glycerin monostearate 1.

Table 1 shows the results of measuring changes over time in the heat retention and water drop prevention properties of the obtained film. Ta.

Comparative Example I A film having a three-layer Santoifuchi structure was formed in the same manner as in Example 1, except that the superabsorbent resin (Sumikagel ■5p-510) was not used for F'3rgJ (drop-proof! fiI). The performance is shown in Table 1. Although the heat retention property was good, the long-term water drop prevention property was not observed, and it was considerably inferior to Example 1.

Comparative Example 2 Super absorbent tree N (Sumikagel ■5P-5
A film having a three-layer structure was subjected to the same tRK as in Example 3 except that 10) was not used. The performance is shown in Table 1, and although the heat retention property was good, the long-term water drop prevention property was not observed, and it was considerably inferior to Example 8.

ゝ＼１、

Claims (1)

[Claims] It has a multilayer film structure of a polyolefin resin composition, and at least one layer on the plant cultivation side and other layers as necessary contain 0 drip-proofing agent per 100 parts by weight of the polyolefin resin.
．． It is a drip-proof layer containing 1 to 5 parts by weight of a super absorbent resin and 0.1 to 15 parts by weight of a super absorbent resin, and at least one other layer contains an infrared wavelength region of 7 to 15 μm absorption per 100 parts by weight of a polyolefin resin. 2 to 2 inorganic fillers with bands
Agricultural film that is a heat retaining layer containing 80 parts by weight.