KR102131398B1 - Coating composition for agricultural film and modified thermoplastic polymer film for agriculture - Google Patents

Abstract

After being packaged in an agricultural house, the initial oil repellency is good, and it is repeatedly contacted with an agricultural house aggregate during long-term use, and even if this contact is made under conditions of repeated drying and wet conditions. Provided is a coating composition for agricultural films capable of maintaining good oil repellency and a modified thermoplastic polymer film using the composition. As the coating composition for agricultural films, an inorganic colloid sol, a specific cellulose derivative, and a water-soluble crosslinking agent were used in a specific ratio.

Description

Coating composition for agricultural film and modified thermoplastic polymer film for agriculture

The present invention relates to a coating composition for agricultural films used as a coating material for agricultural houses, and to a modified thermoplastic polymer film for agriculture to which the coating composition is attached.

Thermoplastic polymer films are widely used as agricultural house coverings. However, since the thermoplastic polymer film itself has hydrophobic properties, there is a problem that it is easy to reduce the transmission of light due to fogging, and as a result, there is a problem that the growth of the crop is defective, and also the problem that the attached water droplets fall causes the disease to the crop. There is also. For this reason, conventionally, the thing which added the anti-fogging agent or coated with the oil-repellent agent is used for the agricultural film (for example, refer patent documents 1-3). However, since these conventional means are packaged in agricultural houses, initial repellency can be obtained, but if they are repeatedly contacted with the house aggregate during long-term use, and further, when such contact is made under the condition of repeated dry and wet conditions, the relic There is a problem that the castle is lost. The actual durability is poor by conventional means.

Japanese Patent Publication No. 9-298954 Japanese Patent Publication No. Hei 11-10783 Japanese Patent Publication No. 2004-255807

The problem to be solved by the present invention is that, after being packaged in an agricultural house, the initial oil repellency is good, and repeatedly contacts the aggregate of the agricultural house during long-term use, and furthermore, such a contact is repeated in a dry state and a wet state. It is to provide a coating composition for agricultural films that can maintain good oil repellency even when made under and a modified thermoplastic polymer film for agriculture using such a composition.

As a result of research to solve the above-mentioned problems, the present inventors have found that an inorganic colloid sol, a specific cellulose derivative, and a water-soluble crosslinking agent in a specific ratio are properly suitable as a coating composition for agricultural films.

That is, the present invention is for agricultural film, characterized in that it contains 30 to 70 mass% of inorganic colloid sol in terms of solid content, 20 to 60 mass% of the following cellulose derivative, and 1 to 30 mass% of water-soluble crosslinking agent. It relates to a coating composition. In addition, the present invention relates to an agricultural modified thermoplastic polymer film to which such a coating composition for agricultural films is attached.

Cellulose derivatives: at least one selected from carboxymethyl cellulose metal salt, hydroxyethyl cellulose, hydroxypropylmethyl cellulose and methyl cellulose

First, the coating composition for agricultural films according to the present invention (hereinafter referred to as the composition of the present invention) will be described. The composition of the present invention is composed of 30 to 70 mass% of the inorganic colloid sol in terms of solid content, 20 to 60 mass% of the cellulose derivative, and 1 to 30 mass% of the water-soluble crosslinking agent. As 40 to 67% by mass, the cellulose derivative containing 30 to 50% by mass and the water-soluble crosslinking agent in a proportion of 3 to 25% by mass, cellulose derivative / water-soluble crosslinking agent = 10/1 to 10/5 (mass ratio) It is preferably made to contain.

Examples of the inorganic colloid sol to be provided in the present invention include so-called silica sol and alumina sol, and commercially available ones can be used, and these may be used alone or in combination. As the silica sol, cationic acidic silica sol such as Snowtex AK and Snowtex AK-L (all are brand names made by Nissan Chemical Co., Ltd.), Snowtex 30, Snowtex 30L, Snowtex ZL (all are brand names manufactured by Nissan Chemical Co., Ltd.) Anionic alkaline silica sol such as Cataloid SI-30, Cataloid SI-45P, and Cataloid SI-80P (all are brand names made by Nikki Catalytic Chemicals), Snowtex O, Snowtex OL (both are all manufactured by Nissan Chemical Co., Ltd.) And anionic acidic silica sol such as Cataloid SN (trade name of Nikki Catalytic Chemical Co., Ltd.), and alumina sol is alumina sol 100, alumina sol 200, alumina sol 520 (all are trade names of Nissan Chemical Co., Ltd.) And cationic acid alumina, such as Cataloid AS-1 and Cataloid AS-2 (all of which are trade names of Nikki Catalytic Chemical Co., Ltd.).

As such an inorganic colloid sol, a silanol-forming organosilane compound is hydrolyzed in the presence of an inorganic colloid sol, and the resulting silanol compound is condensed and polymerized, and a condensation polymerization product is attached to the surface of solid particles of the inorganic colloid sol (hereinafter, , This may be used as a modified inorganic colloid sol). Examples of the silanol-forming organosilane compound used for the modification of the inorganic colloid sol include 1) trialkoxy silanes, 2) dialkoxy silanes, and 3) monoalkoxy silanes. As the trialkoxy silanes, methyl trimethoxy silane, methyl triethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, γ-chloropropyl tripropoxy silane, γ-mercaptopropyl triethoxy silane, γ-glycidoxypropyl trimethoxy silane, γ-methacryloxypropyl triethoxy silane, γ-ureidopropyl trimethoxy silane, phenyl trimethoxy silane, and the like. Examples of the dialkoxy silanes include: Dimethyl dimethoxy silane, γ-chloropropyl methyldimethoxy silane, γ-glycidoxypropylmethyl dimethoxy silane, and the like, and examples of the monoalkoxy silanes include trimethylmethoxy silane. Among them, as the silanol-forming organosilane compound, γ-glycidoxypropyl trimethoxy silane, γ-ureidopropyl trimethoxy silane, and methyl triethoxy silane are preferable. The silanol-forming organosilane compound is preferably used in an amount of 1 to 30 parts by mass based on 100 parts by mass of the solid content of the inorganic colloid sol.

The cellulose derivative provided in the composition of the present invention is at least one selected from carboxymethyl cellulose metal salt, hydroxyethyl cellulose, hydroxypropyl cellulose and methyl cellulose. These may be used alone or in combination. As such a cellulose derivative, it is preferable that the viscosity of the 2 mass% aqueous solution at 20°C is 1 to 600 mPa·s, and more preferably 1 to 400 mPa·s.

Examples of the water-soluble crosslinking agent provided in the composition of the present invention include water-soluble melamine, water-soluble epoxy, water-soluble oxazoline, water-soluble aziridine, and the like, and water-soluble melamine is preferred. As the water-soluble melamine, commercially available ones can be used, for example, NIKALAC MX-035, NIKALAC MW-22, NIKALAC MW-12LF (all of which are trade names of Sanwa Chemical), BECKAMINE M-3, and BECKAMINE MA. -S, BECKAMINE J-101 (all are brand names made by DIC).

The composition of the present invention may further contain polyether-modified silicone. The polyether-modified silicone is used in a ratio of 0.1 to 50 parts by mass based on 100 parts by mass of the solid content of the inorganic colloid sol.

As such a polyether-modified silicone, commercially available ones can be used as they are. As such commercial products, for example, TSF4440, TSF4441, TSF4445, TSF4446, TSF4452, TSF4460 (all are trade names of Momentive Performance Materials Japan), X22-4952, X-22-4272, KF-6123, KF- 351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-644, KF-6204, X-22- 4515, KF-6004 (all are brand names made by Shin-Etsu Silicone Co., Ltd.), SH8700, SH8410, SH8400, L-7002, FZ-2104, FZ-77, L-7604, FZ-2203, FZ-2208 (all above are Toray Dow Corning Co., Ltd.) (Trade name), etc., among them, it is preferable that HLB is 4 to 16, such as TSF4440, KF-354L, KF-945, SH8400, KF-6004, and the like.

Next, the modified thermoplastic polymer film according to the present invention (hereinafter referred to as the film of the present invention) will be described. In the film of the present invention, the composition of the present invention described above is attached to the surface treatment surface of the thermoplastic polymer film as 0.15 to 0.5 g/m ² as a solid content.

As a thermoplastic resin provided to the film of this invention, 1) polyolefin resin, 2) polyvinyl chloride resin, 3) polyester resin, etc. are mentioned. Examples of polyolefin-based resins include homopolymers of α-olefins such as polyethylene and polypropylene, ethylene-propylene copolymers, ethylene·1-butene copolymers, ethylene·4-methyl-1-pentene copolymers, and ethylene 1-hexene copolymers. Copolymers, α-olefin copolymers such as ethylene/1-octene copolymers, ethylene/vinyl acetate copolymers, ethylene/methyl methacrylate copolymers, ethylene/vinyl acetate/methyl methacrylate copolymers, ionomer resins, etc. and copolymers with heterogeneous monomers containing α-olefin as a main component. Examples of polyvinyl chloride-based resins include polyvinyl chloride, vinyl chloride, ethylene copolymer, vinyl chloride, vinyl acetate copolymer, and vinyl chloride, methyl meta. A acrylate copolymer, polyvinylidene chloride, etc. are mentioned, As a polyester resin, polyethylene terephthalate etc. are mentioned. These may be used by blending various types of thermoplastic resins. In particular, a polyolefin-based resin is preferable as the thermoplastic resin. In such a polyolefin-based resin, it is more preferable that the copolymer of α-olefin is obtained by a gas phase method, a solution polymerization method, or the like, using a homogeneous catalyst such as a known high activity Ziegler catalyst and a metallocene catalyst, and the density is Particular preference is given to 0.86 to 0.94 g/cm ³ and MFR of 0.01 to 20 g/10 min. The polyolefin-based resin may be used by mixing two or more polyolefin-based resins. These thermoplastic resins may contain antioxidants, weathering agents, ultraviolet absorbers, infrared absorbers, lubricants, anti-blocking agents, antifogging agents, antifogging agents, thermal insulation agents, pigments, and the like, as necessary.

There is no restriction|limiting in particular as a manufacturing method of the thermoplastic polymer film provided to the film of this invention, For example, an inflation molding method, a T die molding method, etc. are mentioned. The film may be a single-layer film or a multi-layer film, or an unstretched film or a stretched film. For the agricultural film, a thermoplastic polymer film made of the polyolefin-based resin molded by inflation molding is preferable.

The film of the present invention is preferably coated with the composition of the present invention after surface treatment on the surface of the thermoplastic polymer film to which the composition of the present invention is applied. As the surface treatment, corona discharge treatment, atmospheric pressure plasma treatment, flame treatment or the like can be used, but corona discharge treatment is preferred. The wet tension of the surface-treated surface is preferably 35 mN/m or more, and more preferably 35 to 70 mN/m. In the present invention, the wet tension is a value measured in accordance with JIS-K6768.

In the film of the present invention, a known coating method can be used as a method of applying the composition of the present invention to the thermoplastic polymer film. Examples thereof include a gravure coating method, a spray coating method, an immersion coating method, a roll coating method, a doctor blade coating method, a wire bar coating method, and an air knife coating method.

According to the present invention described above, after packaging in an agricultural house, the initial oil repellency is good, and it is repeatedly contacted with the agricultural house aggregate during long-term use, and furthermore, such contact is made under conditions in which the dry state and the wet state are repeated. Even in the case, there is an effect capable of maintaining good oil repellency.

Hereinafter, in order to make the structure and effect of the present invention more specific, examples and the like can be given, but the present invention is not limited to these examples. In addition, in the following examples and comparative examples, parts by mass mean, and% means mass%.

Test division 1 ((modification) preparation of inorganic colloid sol)

39.10 parts of water, 59.61 parts of inorganic colloidal sol (A-1) (23% solids) were mixed, and 1.29 parts of γ-glycidoxypropyl trimethoxy silane was further added with a silanol-forming organosilane compound (D-1). (100% solid content) was mixed to prepare a mixed solution having a solid content concentration of 15%, followed by stirring at 50°C for 5 hours to hydrolyze the silanol-forming organosilane compound (D-1), and additionally produced silanol. The compound was subjected to condensation polymerization to obtain a modified inorganic colloid sol (K-1). In the modified inorganic colloid sol (K-1), a condensation polymerization product of a silanol compound was attached to the solid particles of the inorganic colloid sol. Similarly, modified inorganic colloidal sol (K-2) to (K-5) were prepared. Table 1 summarizes the contents of the modified inorganic colloid sol prepared in each of the above examples.

In Table 1,

Ratio (parts): Solid content conversion ratio (parts)

A-1: Cationic acidic silica sol

A-2: Mixture of cationic acidic silica sol/cationic acid aluminasol = 50/50 (mass ratio)

A-3: Anionic acid silica sol

A-4: Mixture of anionic acidic silica sol/cationic acidic aluminasol = 75/25 (mass ratio)

A-5: Anionic alkaline silica sol

D-1: γ-glycidoxypropyl trimethoxy silane

D-2: γ-ureidopropyl trimethoxy silane

D-3: methyl triethoxy silane

Test Category 2 (Preparation of coating composition for agricultural film)

· Example 1

26.5 parts of modified inorganic colloid sol (K-1) with a solids concentration of 15%, 467 parts of water, 5 parts of a cellulose derivative (B-1), 1.4 parts of a water-soluble crosslinking agent (C-1) with a solids concentration of 70% and polyether-modified silicone (S-1) 0.01 part was stirred to obtain a coating composition for agricultural films (X-1) having a solid content concentration of 2%.

Examples 2 to 27 and Comparative Examples 1 to 5

In the same manner as in Example 1, Examples 2 to 27 and Comparative Examples 1 to 5 coating composition for agricultural films (X-2) to (X-27) and (rx-1) to (rx-5) Got. Table 2 summarizes the contents of the coating composition for agricultural films prepared in each of the above examples.

In Table 2,

(Modification) Ratio of inorganic colloid sol, cellulose derivative and water-soluble crosslinking agent: parts by mass as a solid

Mass ratio: cellulose derivative/water-soluble crosslinking agent

Ratio of polyether-modified silicone: (modified) parts by mass relative to 100 parts by mass of solid content of the inorganic colloid sol

K-1 to K-5: modified inorganic colloidal sol as described in Table 1

A-1 to A-5: Inorganic colloidal sol described in Table 1

B-1: Hydroxypropyl methylcellulose (viscosity rate of 50 mPa·s at 20° C. in a 2% aqueous solution)

B-2: Hydroxypropyl methylcellulose (viscosity of 3% Pa at 20°C in 2% aqueous solution)

B-3: Hydroxypropyl methylcellulose (viscosity rate at 20°C of 2% aqueous solution 400 mPa·s)

B-4: methylcellulose (viscosity of 4% Pa at 20°C in 2% aqueous solution)

B-5: sodium carboxymethylcellulose (viscosity of 150% Pa·s at 20° C. in a 2% aqueous solution)

B-6: Hydroxy ethyl cellulose (viscosity of 100% Pa at 20°C in 2% aqueous solution)

C-1: water-soluble melamine (trade name NIKALAC MX-035 manufactured by Sanwa Chemical)

C-2: Water-soluble melamine (DIC brand name BECKAMINE MA-S)

C-3: Water-soluble melamine (DIC brand name BECKAMINE M-3)

rc-1: water-insoluble melamine (trade name NIKALAC MX-750, manufactured by Sanwa Chemical)

S-1: Polyether modified silicone (HLB = 14)

S-2: Polyether modified silicone (HLB = 16)

S-3: Polyether modified silicone (HLB = 4)

Test Category 3 (Evaluation of coating composition for agricultural film)

The blendability of the coating composition for agricultural films of each example prepared in Test Category 2 was evaluated by the following method. Table 3 summarizes the results.

· Mixability evaluation

After putting the coating composition for agricultural films of each example prepared in Test Category 2 into a sedimentation tube and standing at 20°C for 24 hours, the condition of the coating composition for agricultural films was evaluated based on the following criteria.

Evaluation criteria for solution mixability

◎: Sediment and insoluble materials are not recognized, and the mixing property is excellent.

×: Sediment and insoluble materials are recognized, and poor mixing properties

Test Category 4 (Production of modified thermoplastic polymer film for agriculture)

Example 28

Ethylene·1-butene copolymer (ethylene copolymerization ratio 95%, density 0.920 g/cm ³ , MFR 2.1 g/10 min) was provided to an inflation molding machine equipped with a 75 mm diameter lip spacing 3 mm die, and the resin extrusion temperature. Inflation molding was performed under the conditions of 200° C. and BUR=1.8 to prepare an olefin copolymer film having a thickness of 150 μm. Subsequently, this olefin copolymer film was subjected to corona treatment discharge, and after setting the wetting tension of the corona discharge treatment surface to 42 mN/m, the coating composition for agricultural films prepared in Test Category 2 was applied to the corona discharge treatment surface (X -1) was applied by a gravure coating method so as to be 0.3 g/m ² as a solid content, and stayed for 1 minute in a warm air drying furnace having a temperature controlled at 70° C. to obtain a modified thermoplastic polymer film for agriculture.

Examples 29 to 54 and Comparative Examples 6 to 10

Agricultural modified thermoplastic polymer films of Examples 29 to 54 and Comparative Examples 6 to 10 were obtained in the same manner as in Example 1. Table 3 summarizes the contents of the modified thermoplastic polymer film prepared in each of the above examples.

In Table 3,

F-1: Ethylene·1-butene copolymer (ethylene copolymerization ratio 95%, density 0.920 g/cm ³ , MFR 2.1 g/10 min)

F-2: Ethylene·1-hexene copolymer (ethylene copolymerization ratio 96%, density 0.930 g/cm ³ , MFR 1.0 g/10 min)

F-3: Ethylene-vinyl acetate copolymer (ethylene copolymerization ratio 93%, MFR 1.5 g/10 min)

F-4: polyethylene (density 0.927 g/cm ³ , MFR 4.0 g/10 min)

F-5: Ethylene-propylene copolymer (ethylene copolymerization ratio 4%, density 0.90 g/cm ³ , MFR 8.0 g/10 min)

X-1 to X-27, rx-1 to rx-5: Coating composition for agricultural films in Table 2

Test Category 5 (Evaluation of modified thermoplastic polymer films for agriculture)

About the modified thermoplastic polymer film for agriculture of each example prepared in the test division 4, the evaluation shown below was performed about the coating property of the coating composition for agricultural films, initial dripping property, oil drop persistence, dry scratch resistance, and wet scratch resistance. Table 4 shows the results.

· Applicability evaluation

In the modified thermoplastic polymer film of each example prepared in Test Category 4, the adhesion state of the coating composition was visually observed, and the applicability was evaluated based on the following criteria.

Criteria for applicability evaluation

◎: Coating non-uniformity does not occur, and the adhesion state is uniformly observed.

○: Coating unevenness occurred in a part, but it was adhered almost uniformly, resulting in excellent coating properties.

△: Partial bouncing occurred, and the unattached portion was observed, resulting in poor applicability.

×: It was observed that the entire surface was bounced and was not attached, and thus the coating property was remarkably deteriorated.

· Evaluation of early ruins and ruins persistence

The agricultural modified thermoplastic polymer film of each example prepared in Test Category 4 was packaged in a test house such that the coated surface was inside, and the water droplet adhesion was observed under conditions of a house internal temperature of 30°C, a house external temperature of 10°C, and a 15 degree slope. , The effect of preventing water droplets, that is, the oiliness was evaluated. The time taken until the adhesion area of the water droplets was less than 10% due to the initial oiliness was measured and evaluated based on the following criteria. In addition, with the persistence of the remains, the adhesion state of the water droplets after being placed continuously for 30 days was visually observed and evaluated according to the following criteria.

Evaluation criteria of early ruins

◎: Less than 15 minutes after the exhibition (exhibition is very good).

○: 15 minutes or more and less than 30 minutes after the battlefield (excellent initial ruins).

△: 30 minutes or more and less than 60 minutes after the battlefield (initial ruins are poor).

X: The adhesion area of the water droplets for 60 minutes after the battlefield is 10% or more (initial repellency is significantly reduced).

Criteria for evaluating site sustainability

◎: There is no adhesion of water droplets, and the durability of the remains is very good.

○: The adhesion area of water droplets is less than 10%, and the oil droplet persistence is excellent.

△: The adhesion area of water droplets is 10% or more to less than 50%, and the persistence of oil droplets is poor.

X: The adhesion area of the water droplets is 50% or more, and the persistence of the remains is significantly reduced.

· Dry scratch resistance evaluation criteria

300 g of vinyl tape was applied to the frictional surface of the arm of the friction tester (Gakushin-Type Color Fastness tester, manufactured by Daiei Science and Manufacturing Co., Ltd.) for each modified thermoplastic polymer film for agriculture prepared in Test Category 4. After applying 10 reciprocating friction to 100 cm ² of the coated surface of the agricultural modified thermoplastic polymer film under the condition of applying a load of, water vapor is applied to the rubbed portion to observe the degree of peeling of the coating film from the cloudy portion caused by water droplets attached, and peeling off of the coating film The strength was evaluated according to the following criteria as dry scratch resistance.

Dry scratch resistance evaluation criteria

◎: There is no peeling of the coating film, and the scratch resistance is very excellent.

○: The peeling area of the coating film was less than 10%, and the scratch resistance was excellent.

Δ: The peeling area of the coating film was 10% or more and less than 50%, and the scratch resistance was poor.

X: The peeling area of the coating film was 50% or more, and the scratch resistance was significantly reduced.

· Wet scratch resistance evaluation

The coated surface of the modified thermoplastic polymer film for agriculture in each example prepared in Test Category 4 100 cm ² Water was poured into the wet state, and a vinyl tape was attached to the friction surface of the arm of a friction tester (academic dyeing fastness tester, manufactured by Daiei Science & Machinery Co., Ltd.), and a load of 300 g was applied. After the reciprocating friction, the degree of peeling of the coating film was observed from the cloudy part caused by water droplets attached to the rubbed part, and the peeling strength of the coating film was evaluated by the following criteria as Wet scratch resistance.

Wet scratch resistance evaluation standard

◎: Excellent scratch resistance without peeling of the coating film.

○: The peeling area of the coating film was less than 10%, and the scratch resistance was excellent.

Δ: The peeling area of the coating film was 10% or more to less than 50%, and the scratch resistance was poor.

X: The peeling area of the coating film was 50% or more, and the scratch resistance was significantly reduced.

As can be seen from the results of Table 4 corresponding to Tables 1 to 3, according to the present invention, after being packaged in an agricultural house, the initial oiliness is good, and it is repeatedly contacted with the aggregate of the agricultural house during long-term use In addition, it can be seen that, even when such contact is made under a condition in which the dry state and the wet state are repeated, good oil repellency is maintained.

Claims (8)

A coating composition for agricultural films comprising inorganic colloid sol in a proportion of 30 to 70 mass% in terms of solid content, 20 to 60 mass% of the following cellulose derivative, and 1 to 30 mass% of a water-soluble crosslinking agent:
Cellulose derivatives: at least one selected from carboxymethyl cellulose metal salts, hydroxyethyl cellulose, hydroxypropyl cellulose and methyl cellulose. The coating composition for agricultural films according to claim 1, wherein the cellulose derivative has a viscosity of 1 to 600 mPa·s at 20° C. in a 2% by mass aqueous solution. The coating composition for agricultural films according to claim 1, wherein the water-soluble crosslinking agent is water-soluble melamine. The method according to claim 1, wherein the inorganic colloid sol contains 40 to 67 mass% in terms of solid content, 30 to 50 mass% of cellulose derivative, and 3 to 25 mass% of water-soluble crosslinking agent, and also cellulose derivative/water-soluble crosslinking agent = It is contained in a ratio of 10/1 to 10/5 (mass ratio), coating composition for agricultural films. The coating composition for agricultural films according to claim 1, further comprising polyether-modified silicone in an amount of 0.1 to 50 parts by mass based on 100 parts by mass of the inorganic colloid sol in terms of solid content. A modified thermoplastic polymer film for agriculture, characterized in that 0.15 to 0.5 g/m ² of the coating composition of any one of claims 1 to 5 is attached to the surface treatment surface of the thermoplastic polymer film as a solid content. The modified thermoplastic polymer film for agriculture according to claim 6, wherein the surface treatment is a corona discharge treatment. The modified thermoplastic polymer film for agriculture according to claim 6, wherein the thermoplastic polymer film is a polyolefin resin film.