JPS6042254B2 - Agricultural polyvinyl chloride film - Google Patents

Description

Detailed Description of the Invention The present invention relates to an agricultural polyvinyl chloride film, and more specifically to a polyvinyl chloride film that is less likely to adhere to each other when overlapped (excellent non-adhesive properties) and that retains heat. This invention relates to agricultural polyvinyl chloride film with excellent properties.

In recent years, farmers cultivating useful plants have widely adopted methods of promoting the cultivation of useful plants in greenhouses or tunnels in order to increase profitability.

As the covering material for this house or tunnel, polyvinyl chloride film, polyethylene film, ethylene-vinyl acetate copolymer film, polyethylene terephthalate, rate film, etc. are used. Among them, soft polyvinyl chloride film is used in the largest amount because it is superior in weather resistance, transparency, heat retention, and strength compared to other synthetic resin films. Flexible polyvinyl chloride film is soft and elastic, so it has the advantage of being able to be stretched easily into any shape of house or tunnel. It has a disadvantage in that its properties (so-called tackiness) are greater than polyethylene films and ethylene-vinyl acetate copolymer films.

If the adhesiveness of the film is too high, the efficiency of spreading the film onto the house or tunnel will decrease, and the efficiency of bonding the films together using the high-frequency/wave bonding method will also decrease. Alternatively, there is a problem that the ventilation work in the tunnel and the opening/closing work of the house or tunnel are reduced. The adhesion, quality, and
That is, there are the following aspects as cases where adhesiveness is exhibited.

(1) Adhesion at low temperatures A phenomenon observed when handling soft polyvinyl chloride films at relatively low temperatures of 40°C or lower.

In this case, no fusion phenomenon is observed. (2) Adhesion at high temperatures When soft polyvinyl chloride film is used as a covering material for a house or tunnel, the films are stacked or bundled outdoors to ventilate the inside of the house or tunnel. , often exposed to direct sunlight.

In this case, the film temperature rises to 40-80°C. At such high temperatures, the films adhere to each other, and in some cases even fuse, and even when the temperature of the films drops, it takes considerable effort to separate the films from each other. reach. (3) Adhesiveness at high temperatures and in wet conditions This is the same phenomenon as in (2), but when stacked or bundled films are exposed to high temperatures while in a wet condition, moisture between the films increases. After evaporating,
Causes severe adhesion.

Many techniques have been proposed and some have been put into practical use to eliminate the tackiness of such soft vinyl chloride films to make them non-adhesive (improve the non-adhesion). Techniques for improving the non-adhesive properties of agricultural polyvinyl chloride films include methods of forming films by blending various anti-blocking agents with the base polyvinyl chloride, methods of forming films by blending inert solid fine particles, and There are methods that combine both of these methods.

Various anti-blocking agents are added to the base polyvinyl chloride. The problem with this method is that it is difficult to improve the non-stick properties at low temperatures. A film containing an anti-adhesive agent exhibits an anti-adhesive effect because the anti-adhesive agent is sprayed onto the film surface. Anti-blocking agents are generally
It is difficult to spray out onto the surface of the film at low temperatures, and in order to exhibit non-stick properties even at low temperatures, the blending amount must be increased. If a large amount of anti-adhesive is added, the anti-adhesive will spray out more at high temperatures and the transparency of the film will decrease, and while it is used as a covering material for the house or tunnel 1, dust will adhere to it and the transparency will increase. The disadvantage is that the performance is reduced. One method for improving non-adhesion by blending various inert solid particles into a film is to roughen the surface of the film with the inert solid particles.

In order to roughen the film surface, it is necessary to increase the amount of inert solid fine particles added, which inevitably reduces the transparency of the film. Although this method can improve the non-tackiness of the film at low temperatures, it is not very effective in improving the non-tackiness at high temperatures or in wet conditions. As a method that combines both of these methods, methods described in Japanese Patent Publication No. 54-30698 and Japanese Patent Application Laid-Open No. 55-43114 have been proposed.

The method described in Japanese Patent Publication No. Sho M-30698 is based on the basic composition 7 for producing a flexible polyvinyl chloride film, which has a melting point of 6.
It is made into a film by blending a lubricant with a temperature of 0° C. or higher and inert solid fine particles with a particle size of 0.05 to 10 microns.

However, the combination of a lubricant with a temperature of 60°C or higher and inert solid particles with a particle size of 0.05 to 10 microns has the effect of improving non-adhesive properties in all three cases where the film exhibits adhesion. It is not something that can be demonstrated. Recently, agricultural polyvinyl chloride films have been required to exhibit even better heat retention properties in addition to the above-mentioned excellent non-stick properties.

In order for agricultural polyvinyl chloride film to exhibit excellent heat retention properties, (a) sunlight must be able to penetrate as much as possible into the greenhouse or tunnel during irradiation with solar rays; (b) sunlight. It is necessary to have two properties: to prevent the release of the heat accumulated in the soil heated by sunlight as much as possible.In order to satisfy property (a) above, the polyvinyl chloride film must be transparent. In order to satisfy property (b) above, heat rays emitted from the soil (corresponding to wavelengths in the infrared region in the range of 5 microns to 25 microns) must be directed outside the house or tunnel. As a method for improving the heat retention of a synthetic resin film for covering a house or tunnel, a technique described in JP-A-55-43114 has been proposed. In this method, inert solid fine particles having absorption ability in the infrared region are added to a synthetic resin film.However, these conventional techniques have the following problems: (1) Inert solid particles are added to the synthetic resin raw material. When blending and mixing solid particles, powdering of the solid particles tends to occur, reducing the efficiency of blending and mixing.

(2) Also, since solid particles have a small bulk specific gravity,
It is lightweight and bulky, and even when blended and mixed with the raw synthetic resin, it is difficult to uniformly disperse the two.

(3) In order to improve the drawbacks of (1) and (2) above, if solid particles with a large particle size are used, the final film surface will be rough and pinholes will occur on the film surface. The tear strength of the film decreases.

Furthermore, the transparency of the film also decreases. (4) Inert solid particles generally have a high hardness, so in the process of blending and mixing raw material synthetic resin and forming into a film, they wear out and damage the mixer and film forming machine, and also cause wear and tear. Metal powder gets mixed into the synthetic resin film, causing the film to become discolored and its weather resistance to deteriorate.

(5) In order for an agricultural synthetic resin film to exhibit heat retention properties, it is necessary to have properties (a) (transparency of the film) and properties (b) (heat retention), and (b). In order to improve the properties, inert solid fine particles are blended, but this is not preferred because the properties of (a) deteriorate.

Further, with the conventional technology, it is difficult to prevent heat rays in the range of 5 microns to 25 microns from being emitted outside the house over the entire range. Under such circumstances, the present inventors aimed to eliminate various problems in the film forming process in the prior art, and to provide a synthetic resin film for agricultural use with improved non-adhesion and heat retention properties and excellent quality. As a result of intensive study, we have completed the present invention.

Therefore, the gist of the present invention is to add a polyvinyl chloride resin composition containing a plasticizer, an anti-blocking agent (a) having a melting point of 130°C or higher, and an adhesive having a melting point in the range of 70 to 120°C. Inhibitor (mouth) and wavelength from 5 microns to 25
Absorbs in the infrared region in the micron range, has a bulk specific gravity of 0.1 y/d or more, and has an average particle size of 0.5 micron to 1.
0 micron and a Mohs hardness of 4 or less inert solid fine particles (c) blended into a film and having a straight light transmittance of 75% or more at a wavelength of 555 millimicrons. Found in vinyl chloride film.

The present invention will be explained in detail below.

In the present invention, polyvinyl chloride refers to polyvinyl chloride, a copolymer mainly composed of vinyl chloride and a monomer copolymerizable with this; and a copolymer mainly composed of polyvinyl chloride and other polymers. , and also includes blends with copolymers.

The film of the present invention is formed from a flexible compounded polyvinyl chloride composition.

To obtain a soft blend, about 30 to 6 parts of a liquid plasticizer is blended to 100 parts by weight of the above-mentioned polyvinyl chloride. Preferred liquid plasticizers in the present invention include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, didodecyl phthalate, and diundecyl phthalate; isophthalic acid derivatives such as diisooctyl phthalate; Acid derivatives; adipic acid derivatives such as di-n-butyl adipate and dioctyl adipate; maleic acid derivatives such as di-n-butyl maleate; citric acid derivatives such as tri-n-butyl citrate; itaconic acid derivatives such as monobutyl itaconate; butyl Oleic acid derivatives such as oleate; ricinoleic acid derivatives such as glyceryl monoricinolate; and others such as tricresyl phosphate, epoxidized soybean oil, and epoxy resin plasticizers. Further, a heat stabilizer, an antistatic agent, an antifogging agent, an ultraviolet absorber, a pigment, a dye, etc. can be added to the polyvinyl chloride before the film forming step, if necessary.

Heat stabilizers that can be blended include stearic acid, zinc stearate, fatty alcohol, calcium stearate, barium stearate, barium ricinoleate, dibutyltin dilaurate, dibutyltin dimaleate, etc. Antistatic agents 7 or antifog Examples of the agent include nonionic surfactants, polyoxyethylene glycerin monostearate, etc., and examples of the UV absorber include hydroquinone UV absorbers, salicylic acid UV absorbers, benzophenone UV absorbers, and benzo9-triazole UV absorbers. Examples include ultraviolet absorbers.

Of course, these resin additives are not limited to those exemplified. These resin additives are used in a usual amount, for example, 5 parts by weight or less per 100 parts by weight of the resin.

The agricultural polyvinyl chloride film according to the present invention contains an anti-blocking agent (a) having a melting point of 130°C or higher and a melting point of 70 to 12°C.
It is made by blending and mixing an anti-blocking agent (1) with a temperature range of 0°C and inert solid fine particles (3) with specific properties.

The anti-blocking agent (a) whose first component has a melting point of 130°C or higher is
Of the three modes in which the film exhibits adhesiveness, mainly (2)
It functions to significantly improve non-stick properties at high temperatures and (3) non-stick properties at high temperatures and in wet conditions.

If only an antiblocking agent with a melting point lower than 130° C. is used, (2) non-stick properties at high temperatures and (3) non-stick properties at high temperatures and in wet conditions cannot be improved. Melting point is 130℃
Specific examples of the above anti-blocking agents include fatty acids and their derivatives, fatty acid amides, higher alcohols and their derivatives, natural waxes, etc., but are not limited to these. Of course, any adhesive having an anti-blocking agent with a melting point of 130° C. or higher can be used. Among the above compounds, fatty acid amides,
For example, methylene bis stearamide and ethylene bis stearamide are particularly suitable. These may be used alone or in combination of two or more. The second component, an anti-tack agent with a melting point in the range of 70 to 120°C, significantly improves (1) non-tackiness at low temperatures among the three aspects in which the film exhibits tackiness. It is something that fulfills a function.

If the melting point of this second component is lower than 70°C, not only will the non-stick property at low temperatures not be improved, but also the non-stick property improving effect at high temperatures, high temperatures, and wet conditions will be inhibited, which is undesirable. If the temperature is 120° C. or higher, non-stick properties at low temperatures will not be improved, which is not preferable. Specific examples of anti-blocking agents with melting points in the range of 70 to 120°C include fatty acids and their derivatives, fatty triacid amides,
Examples include, but are not limited to, higher alcohols and their derivatives, and alcohols with a melting point of 70 to 12
Of course, it can be used within the range of 0°C. Among the above compounds, fatty acid amides such as stearic acid amide, palmitic acid amide, oleic acid amide, etc. are particularly preferred. These may be used alone or in combination of two or more. If the ratio of the first component and the second component is too small, the non-adhesive property improving effect will not be exhibited, which is not preferable, and if it is too large, the problem of spraying onto the film surface will occur, which is not preferable. The amount added varies depending on the type of anti-blocking agent and the thickness of the film, but it is best to add 0.05 to 1.0 parts by weight of both components per 100 parts by weight of the base, and the total amount of both components 1
．． Preferably, the amount does not exceed 5 parts by weight. The third component has absorption in the infrared region with a wavelength in the range of 5 microns to 25 microns, has a bulk specific gravity of 0.1y/al or more, and has an average particle size of 0.5 microns to 10 microns.
Moreover, they are inert solid fine particles having a Mohs hardness of 4 or less.

This third component prevents heat rays in the infrared region with wavelengths ranging from 5 microns to 25 microns from being emitted outside the house, and also works as an anti-blocking agent for the film, especially at low temperatures, along with the second component. It functions to improve the non-stick properties of the film at times. If the bulk specific gravity of this third component is smaller than 0.1y/Cll,
Generally, compared to polyvinyl chloride powder, which is the base material, it is lighter and bulkier, so it tends to cause dusting, which reduces work efficiency during compounding and mixing, and it is difficult to uniformly disperse it into the polyvinyl chloride base material. This is because it becomes.

Furthermore, the reason why the average particle size is set in the range of 0.5 micron to 10 micron is that if it is smaller than 0.5 micron, it is difficult to roughen the film surface and the non-adhesive property improvement effect at low temperatures cannot be achieved. If the diameter is larger than 10 microns, the transparency of the film decreases, pinholes are likely to occur on the film surface, and the strength decreases significantly. Next, the reason why the Mohs hardness is set to 4 or less is that if the hardness exceeds 4, these devices will be worn out and damaged during the mixing process with the base polyvinyl chloride and the process of forming the mixture into a film. This is because the metal powder mixed with the polyvinyl chloride film may be mixed into the polyvinyl chloride film, causing problems such as coloring of the film and deterioration of weather resistance. Specific examples of the third component include feldspar, calcium carbonate, magnesium carbonate, magnesium silicate, talc, aluminum hydroxide, etc., but are limited to those listed as long as they meet the above requirements. isn't it.

The third component absorbs heat rays in the infrared region with wavelengths ranging from 5 microns to 25 microns and prevents them from being emitted outside the house, but it is difficult to satisfy this property with just one type. Therefore, it is preferable to use two or more kinds together. If the blending ratio of the third component is too small, it will be difficult to roughen the film surface, and the effect of improving non-uniform tackiness at low temperatures will not be exhibited.

On the other hand, if the amount is too large, the effect of improving the non-tackiness at low temperatures can be exhibited, but the transparency of the film decreases, which is not preferable. The optimum blending ratio varies depending on the average particle size of the inert solid fine particles, the thickness of the film, etc., but is usually 0.5 to 1 part by weight per 10 parts by weight of one substrate. The above three ingredients are blended into the base polyvinyl chloride,
For mixing, conventional mixing and mixing techniques can be used, such as a pump blender, Panbury Mixer J, or other blender or mixer.

The agricultural polyvinyl chloride film according to the present invention is made by blending and mixing the above three components, and has a straight light transmittance of 75% or more at a wavelength of 555 millimicrons.

This is because if the straight light transmittance is less than 75%, it is not suitable as a material for covering a house. The thickness of the agricultural polyvinyl chloride film according to the present invention is preferably 0.05 rIun or more, and the upper limit is 0.3T
A value of about 1 is preferable.

In order to produce the agricultural polyvinyl chloride film according to the present invention, conventional film production methods such as calendering, extrusion, and inflation can be used. A molding method etc. can be adopted as appropriate. The agricultural polyvinyl chloride film according to the present invention has the following characteristics, and its agricultural utility value is extremely large.

1 The agricultural polyvinyl chloride film according to the present invention contains two anti-blocking agents with different melting points, and also contains inert solid fine particles with a specific particle size, so that the film is non-stick at low temperatures. Not only the tackiness is improved, but also the non-tackiness at high temperatures and under high temperature and humidity conditions is also improved.

2. The agricultural polyvinyl chloride film according to the present invention contains inert solid fine particles that absorb heat rays, so the heat rays emitted from the soil are not released outside the greenhouse or tunnel, and it has excellent heat retention properties. .

3. Since the agricultural polyvinyl chloride film according to the present invention uses inert solid particles having a specific bulk specific gravity, the film manufacturing efficiency does not decrease and the solid particles can be uniformly dispersed. .

4. Since the inert solid fine particles have a specific particle size, the agricultural polyvinyl chloride film according to the present invention not only has improved non-stick properties at low temperatures, but also
Pinholes are hard to form on the film surface, and it has excellent transparency.
It also has excellent tear strength.

5. Since the agricultural polyvinyl chloride film according to the present invention uses inert solid particles having a specific hardness, the molding machine will not be worn out or damaged in the film manufacturing process, and will not be worn out or damaged. The film will not be colored or its weather resistance will be deteriorated by the metal powder.

Below, the agricultural polyvinyl chloride film according to the present invention,
Although the present invention will be described in detail based on examples, the present invention is not limited to the following examples unless it exceeds the gist thereof.

Examples 1 to 6, Comparative Examples 1 to 11 Polyvinyl chloride (F=1400)...10 salivary parts Dioctyl phthalate...50 Tricresyl phosphate...5 Epoxidized soybean oil (product name 0-130)
...3 Barium-zinc composite liquid stabilizer ...1.5 Barium stearate
...0.2〃Zinc stearate...
...0.4 Sorbitan monopalmitate ...
A resin composition consisting of 1.5 was prepared, and an antiblocking agent and inert solid fine particles of the type and amount shown in Table 1 were blended therein.

After stirring and mixing each formulation with a super mixer,
Knead on a mill roll heated to 65℃,
n! A film of FL thickness was prepared.

Table 1 shows the quality evaluation results for each film. The quality evaluation and judgment methods were as follows. (1) The presence or absence of powder was visually observed.

Those in which no dust was observed were classified as RO, and those in which dust was observed were classified as 1×. (2) Dispersibility of inert solid particles An anti-tack agent and inert solid particles were blended into the resin composition, stirred and mixed in a super mixer, and a portion of the mixture was taken and visually observed and judged.

A case in which the inert solid fine particles were almost uniformly dispersed was rated as 1○, and a case in which the dispersion was extremely uneven was rated as 1×. (3) Raw materials worn by molding equipment were stirred and mixed in a super mixer, and then a portion of the mixture kneaded on a mill roll was taken and qualitatively analyzed for metals using a conventional method.

The case where no metal derived from the molding equipment material was detected was set as 10, and the case where it was detected was set as 0x. (4) The presence or absence of pinholes was visually observed.

Those in which no pinholes were observed were defined as ROJ, and those in which pinholes were observed were defined as 1×. (5) Coloring status was observed with the naked eye.

The uncolored one is RO, and the colored one is 1x.
The colors are also listed. (6) Straight light transmittance at 555 TTL μ Measured using a spectrophotometer model 323 manufactured by Hitachi, Ltd.

(7) Ejection property of additive after 3 months The film was left in a chamber for 3 months and the surface of the film was lightly rubbed with a fingertip to judge.

ROJ is the one that leaves almost no finger marks on the surface. A sample with slight finger marks was graded 1Δ, and a sample with significant finger prints was graded 1×. 8) Two films with adhesiveness of 3 h x 100 - were stacked and pressed together with rubber rolls to eliminate air between the films and bring them into close contact.

This tightly attached film is heated to a predetermined temperature (30℃, 50℃,
80° C.) and kept at this temperature for 2 hours. Next, take it out of the oven and let it cool to room temperature for 1 hour.
After being left for 5 minutes, the two films were peeled off using a tensile tester, and the adhesion was evaluated based on the peel stress at that time. Peeling stress (F) is 1y/Cm or less: 1◎, 1
〈1○ for F≦2, ROxyo for 2〈F≦5,
Those with 5<F≦10 are shown as 1△, and those with 10<F are shown as 1×.

]) Heat retention An open tunnel with a diameter of 2 m and a length of 27 TL was set up in a field in Isshi District, Mie Prefecture, and the tunnel was covered with each film, and the temperature inside the tunnel at night was measured at the center of the tunnel.

The measurement period was from November 10th to November 1st, 1937.
For 5 days leading up to the 4th day, the temperature was measured every hour from 6:00 pm to 6:00 am the next day, and the temperature during this period was averaged to obtain the daily average value, and then the average value for the 5 days was calculated. Shown as temperature. From Table 1, the following becomes clear.

In order to improve the adhesion of the film, when only an anti-adhesion agent is added, the non-adhesion of the film at low temperatures is improved (see Comparative Example 1). When the amount is increased, the non-stick property at low temperatures is improved, but the additives are more likely to spray out onto the film surface (see Comparative Example 2).

In addition to the anti-blocking agent, if the melting point of the anti-blocking agent does not meet the requirements of the present invention even if inert solid fine particles are added as a third component, it is necessary to improve the non-stick properties of the film at low temperatures. is not sufficient, promoting tackiness at high temperatures, high temperatures, and humidity (see Comparative Examples 5 and 6), and increasing the content of the third component significantly impairs transparency (see Comparative Example M). When only the first component or the second component is used as an anti-adhesive agent, and this is used in combination with inert solid fine particles, the non-adhesive property of the film at low temperatures is not sufficiently improved (see Comparative Examples 3 and 4). ).

If the bulk specific gravity of the inert solid fine particles blended as the third component is less than 0.1 g/C7l, powder will occur during film processing, resulting in a disadvantage that the particles will not be uniformly dispersed in the film (see Comparative Example 7). ).

Furthermore, when inert solid fine particles with high Mohs hardness are used, molding equipment may be worn and damaged (see Comparative Example 8).
. When inert solid fine particles having an average particle diameter of more than 10 microns are included, pinholes occur frequently in the film (see Comparative Example 9). On the other hand, the agricultural polyvinyl chloride film according to the present invention has a
It has excellent non-adhesive properties in a wide temperature range of °C and also has excellent heat retention properties (see Examples 1 to 6).

Claims (1)

[Claims] 1. A polyvinyl chloride resin composition containing a plasticizer, an anti-blocking agent (a) with a melting point of 130°C or higher, and a melting point of 7
Anti-blocking agent (b) in the range of 0 to 120°C and wavelength of 5
Absorbs in the infrared region in the range of microns to 2.5 microns, has a bulk specific gravity of 0.1 g/cm^3 or more, an average particle size of 0.5 microns to 10 microns, and has a Mohs hardness of 4 or less. Active solid fine particles (c) are blended into a film, and the straight light transmittance at a wavelength of 555 microns is 7.
An agricultural polyvinyl chloride film characterized by having a content of 5% or more. 2. A patent characterized in that the anti-blocking agent (a) with a melting point of 130°C or higher and the anti-blocking agent (b) with a melting point in the range of 70 to 120°C are selected from fatty acid amide compounds. Agricultural polyvinyl chloride film according to claim 1. 3. The agricultural polyvinyl chloride film according to claim 1 or 2, wherein the inert solid fine particles are talc.