JPH0940941A - Antifogging agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antifogging agent composition which can form a coating film having excellent adhesion to an agricultural synthetic resin film and improved persistency of antifogging properties. SOLUTION: This antifogging agent composition is prepared by dispersing the three main components of a crystalline trilayer structure-nonlimitedly layer- expansible clay mineral, an acrylic resin containing 1-10wt.% acid-group- containing vinyl monomer and 5-30wt.% hydroxy vinyl monomer as comonomers and having a glass transition temperature of 40-75 deg.C and a nonionic surfactant in a liquid dispersion.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fogging agent composition which is applied to a substrate film made of synthetic resin to impart anti-fogging properties, and particularly to anti-fogging agricultural synthetic resin films coated with said anti-fogging agent. The present invention relates to an antifogging agent composition with improved durability.

[0002]

2. Description of the Related Art In recent years, so-called "house cultivation" and "tunnel cultivation", in which useful crops are cultivated under a cover of an agricultural film such as an agricultural synthetic resin film, for the purpose of short-term or out-of-season cultivation of crops, have been widely practiced. is As a synthetic resin film used for these, soft vinyl chloride film was widely used because of its excellent light transmittance, heat retention, and anti-fogging properties. Multilayer films such as ethylene-vinyl acetate copolymer/polyethylene laminated in two or three layers have also come into use.
However, soft vinyl chloride films and multi-layer films
Since both are originally hydrophobic, part of the water vapor evaporated from the covered ground surface and crops condenses on the film surface to form water droplets, which hinder the transmission of sunlight, impeding the growth of crops, and Water droplets formed on the surface of the film fall and damage seedlings of agricultural crops, causing problems such as disease.

[0003] In order to solve this problem, anti-fogging agents have been kneaded into the raw material of the film or applied to the surface of the film to prevent fogging of the film surface. However, when the antifogging agent is kneaded into the raw material of the film, the kneaded antifogging agent spouts out to the surface and flows out with water droplets.

[0004] When applying an anti-fogging agent to the surface of a film,
Various antifogging agent compositions have been proposed.
For example, Japanese Patent Publication No. 64-5078 describes an antifogging agent composition comprising an inorganic colloidal sol obtained by mixing an alumina sol and a silica sol, a nonionic surfactant, and water. Although it has excellent wettability and initial antifogging properties, it has a problem in maintaining antifogging properties due to weak adhesion to substrates. Further, in order to improve adhesion, for example, in JP-B-64-2158, a copolymer containing a hydroxyl group-containing vinyl monomer as a main component and a small amount of an acid group-containing vinyl monomer is mixed with an alumina sol and a silica sol. and an antifogging agent composition comprising an inorganic colloidal sol and a nonionic surfactant.
This anti-fogging agent contains an acid group-containing vinyl monomer (for example, acrylic acid) in the polymerization component, so that the adhesiveness is improved, but since the main component of the copolymer is the hydroxyl group-containing vinyl monomer, Water resistance is inferior and sufficient anti-fogging properties cannot be maintained.
Furthermore, JP-B-6-47668 proposes an anti-fogging agent composition comprising a hydrophobic acrylic resin emulsion and silica sol or alumina sol. It is very difficult to select machines and conditions. Furthermore, the antifogging property itself is also insufficient. When a surfactant is added to this antifogging composition, there arises a problem that the transparency and durability of the antifogging property of the film are lowered.

[0005]

SUMMARY OF THE INVENTION The present inventors have solved the above-mentioned drawbacks, and have improved the wettability to the substrate film, the adhesion of the coating film,
In order to provide an anti-fogging composition that improves water resistance and imparts long-term anti-fogging properties, the present invention was completed as a result of various studies. It is an object of the present invention to provide an antifogging composition that provides a coating film having good adhesion to a substrate film.

[0006]

[Means for Solving the Problems] The gist of the present invention is a three-layer crystal structure of unlimited layer expansion clay clay mineral, an acrylic resin having a glass transition temperature of 40° C. to 75° C., and a nonionic surfactant. It is an antifogging composition comprising three components as main components dispersed in a liquid dispersion containing water and/or an alcoholic solvent. That is, in the present invention, as the inorganic colloid sol, the unlimited layer expansion type clay having a lattice that expands in a crystal three-layer structure is used, so that the adhesion to the substrate is better than that of the conventionally known colloidal silica and colloidal alumina. Not only does it have excellent properties, it also has good compatibility with surfactants, so it does not easily settle in the antifogging agent coating solution.
By using an acrylic resin having a glass transition temperature of 40° C. to 75° C. as the resin component, a coating film which is resistant to hydrolysis can be formed.

[0007] Next, the present invention will be described in detail. The fat-expanded clay minerals of the unlimited layer type having a crystal three-layer structure and an expanded lattice in the present invention include trioctahedral, dioctahedral, etc., also called smectite, and specifically montmorillonite mineral group. The following minerals belong to this group of minerals: _{Montmorillonite ( OH} ) _{4Si3 ( Al3.34Mg0.66} ) _{O20.Na0.66Beidellite ( OH ) 4 ( Si6.34Al1.66 ) Al4.34 ) O20.Na0 . 66Nontronite ( OH} ) _{4 ( Si1.34Al0.66} ) _Fe4 ) _O20・_{Na0.66Hectorite ( OH} ) _{4Si8 ( Mg5.34Li0.66} ) _{O20 ・ Na 0.66 Sabonite} (OH) ₄ (Si _7.34 Al _0.66 ) _{Mg 6 O 20} ·Na _{0.66 In} the present invention, the diameter of the unlimited layer expanded clay mineral having an expanded lattice with this crystal three-layer structure is 20-30 nm and the thickness is 0.
It is preferably used as tablet-like (thin plate-like) particles of 5 to 2 nm. That is, by forming such a thin plate, there is no irregular reflection as in the case of a spherical shape, so that it has transparency, and as a result, the amount that can be added to the acrylic polymer solution can be increased. The amount of the unlimited layer fat-swelling clay particles to be blended is 100 to 4 parts per 100 parts by weight of the solid content of the acrylic resin.
00 parts by weight, preferably about 150 to 250 parts by weight. 1 per 100 parts by weight of acrylic resin solid content
If it is less than 00 parts by weight, the anti-fogging property imparted to the synthetic resin film is not sufficient.

The acrylic resin used in the present invention is a homopolymer of acrylic acid ester and methacrylic acid ester monomers, a copolymer thereof, or a vinyl monomer copolymerizable with acrylic acid ester and methacrylic acid ester. It is a copolymer with Acrylic acid ester and methacrylic acid ester monomers include acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate and 2-hydroxy methacrylate.
Vinyl monomers copolymerizable with these monomers include acrylic acid, maleic acid, methacrylic acid,
Acrylamide, methacrylamide, N-methylolacrylamide, acrylonitrile, styrene, vinyl acetate and the like. The acrylic resin used in the present invention must have a glass transition temperature Tg of 40°C to 75°C. That is, acrylic resins with a Tg of less than 40°C have excellent adhesion but poor durability, and their antifogging properties decrease over time.
It is not preferable because it has poor adhesion and adversely affects the anti-fogging property itself. In the present invention, it is preferable to use an acrylic resin composition containing 1 to 10% by weight of an acid group-containing vinyl monomer and 5 to 30% by weight of a hydroxyl group-containing vinyl monomer.

[0009] The nonionic surfactant in the present invention is
It brings about effects such as improved dispersibility of the antifogging agent composition, improved wettability during surface treatment, and improved antifogging properties after treatment. Types of nonionic surfactants that can be used include polyoxyethylene sorbitan fatty acid esters, polyoxyethylene ethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, sugar esters, fluorine-based surfactants, and the like. can be used, but are not limited to these types of nonionic surfactants. The amount of the nonionic surfactant added is preferably 2 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the acrylic resin.
At 2 parts by weight or less, the wettability of the antifogging agent composition to the substrate,
The anti-fogging property is poor, and if it is 10 parts by weight or more, the strength of the coating film after forming the coating film is lowered, and as a result, the anti-fogging property cannot be maintained.
In addition, the mixing ratio of the nonionic surfactant and water is 100% water.
It is preferable to use it in an amount that gives a ratio of 0.5 parts by weight or less to parts by weight.

[0010] Further, in the present invention, it is preferable to incorporate a cross-linking agent into the composition. In other words, by blending a cross-linking agent, cross-linking of the acrylic resin is promoted, and water resistance can be improved. As the cross-linking agent, an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent can be used. In addition, if necessary, conventional additives such as pigments, dispersants and antifoaming agents may be added. The method for preparing the antifogging agent composition of the present invention is not particularly limited, and it may be added in any order or simultaneously to a dispersion comprising water and/or an alcoholic solvent.

The substrate to which the antifogging agent composition of the present invention is applied may be either a monolayer film of thermoplastic resins such as EVA, polyethylene, or polypropylene, or a multilayer film obtained by laminating these thermoplastic resin films. especially,
It is suitable for multi-layer films composed of ethylene-vinyl acetate copolymer and polyethylene, which are widely used in the field of agriculture in recent years. When applying the antifogging composition to a substrate, it is highly preferred to carry out a preliminary treatment such as treatment with corona discharge or plasma treatment.

When the antifogging agent composition of the present invention is applied to a substrate, any method such as gravure coating, roll coating, spray coating, bar coating, knife coating, etc. may be used, and the coating weight after application is 0.1. ~3 g/ ^m2 is preferred. Drying after coating is generally performed by hot air drying, but natural drying by sunlight after spreading the base material is also possible. In the case of hot air drying, temperatures in the temperature range of 50°C to 120°C are preferred. The coating film formed by applying the antifogging composition of the present invention and drying with hot air exhibits hydrophobicity and is difficult to hydrolyze.

[0013]

EXAMPLES The present invention will now be described with reference to examples. Acrylic resin compositions (AC-1 to AC-
14) is shown in Table 1. The abbreviations of the names in Table 1 are as follows. MMA methyl methacrylate BMA butyl methacrylate EHA 2-ethylhexyl acrylate HEMA 2-hydroxy methacrylate AA acrylic acid MAA methacrylic acid Tg Glass transition temperature of acrylic resin IPA isopropyl alcohol

[0014]

[Table 1]

Examples 1 to 10 Using the solutions of the acrylic resin compositions shown in Table 1 and the 4% dispersion of hectorite, antifogging agent compositions having the proportions shown in Table 2 were prepared. A solid content of 0.00 was applied to a corona-discharge-treated polyethylene film by a spray coating method.
8 g/m ² was applied and dried with hot air at 90° C. for 5 minutes. The polyethylene film thus obtained was placed in a constant temperature water bath as shown in FIG. Table 2 shows the results. The 4% dispersion of hectorite in Table 2 has a diameter of 20 to 30 nm and a thickness of 0.5 to 2 nm.
4 parts by weight of tablet-like hectorite of m is dispersed in a dispersion medium of 48 parts by weight of isopropanol and 48 parts by weight of water. Other talcs in Table 4, montmorillonite, beidellite, nontronite, hectorite,
A 4% dispersion of sabonite is similarly prepared. The particle size of these mineral powders is 20-30 nm. Also, AC-1
The solutions of ~14 are 50% solids products. The antifogging test results were visually evaluated according to the following criteria. a Good anti-fogging property b Fairly good anti-fogging property c Poor anti-fogging property

[0016]

[Table 2]

Comparative Examples 1 to 7 Using the acrylic resin composition solutions and the 4% dispersion of hectorite shown in Table 3, antifogging compositions having the proportions shown in Table 4 were prepared. 0.8 g solid content by spray coating on corona discharge treated polyethylene film
/m ² , dried with hot air at 90°C for 5 minutes, and tested for anti-fogging properties by the same test method as in the examples. Antifogging evaluation is the same as in Examples. Table 3 shows the results.

[0018]

[Table 3]

Comparative Example 8 and Examples 11 to 15
An anti-fogging agent composition was prepared from the various crystal three-layer structures shown in Fig. 1 and an unlimited layer expansion type clay mineral dispersion, and the anti-fogging property and transparency were measured by the same method as in the previous examples and comparative examples. did. Table 4 shows the results.

[0020]

[Table 4]

[0021]

INDUSTRIAL APPLICABILITY As described above, in the present invention, there are three components: clay clay with a three-layer crystal structure and unlimited layer expansion, an acrylic resin having a glass transition temperature of 40°C to 75°C, and a nonionic surfactant. As a result of applying an antifogging composition mainly composed of could get things.

[Brief description of the drawing]

FIG. 1 is a perspective view of a house used to examine the antifogging properties of a film coated with the antifogging agent composition of the present invention;

[Written Amendment]

[Submission date] October 2, 1995

[Procedural amendment 1]

[Name of document to be amended] Description

[Name of item to be corrected] Claims

[Correction method] Change

[Correction details]

[Claims]

[Procedural amendment 2]

[Name of document to be amended] Description

[Correction target item name] 0006

[Correction method] Change

[Correction details]

[0006]

[Means for Solving the Problems] The gist of the present invention is a crystal three-layer structure unlimited layer expansion type clay mineral and an acid group-containing clay mineral.
1 to 10% by weight of a vinyl monomer and a hydroxyl group-containing vinyl monomer
5 to 30% by weight of the polymer is dispersed in a liquid dispersion containing three main components: an acrylic resin having a glass transition temperature of 40°C to 75°C, and a nonionic surfactant. It is an antifogging composition. That is, in the present invention, as an inorganic colloid sol, an unlimited layer expansion type clay having a lattice that expands in a crystal three-layer structure is used , and a resin component and
and an acid group-containing vinyl monomer and a hydroxyl group-containing vinyl monomer
containing a copolymer of and an acrylate, and a glass transition
By using an acrylic resin with a transfer temperature of 40°C to 75°C , not only is it superior in adhesion to the substrate compared to conventionally known colloidal silica and colloidal alumina, but it is also a surfactant. Because of its good compatibility with the antifogging agent, it is possible to form a coating film which is less likely to settle in the antifogging agent coating solution and which is less likely to be hydrolyzed.

[Procedural amendment 3]

[Name of document to be amended] Description

[Correction target item name] 0007

[Correction method] Change

[Correction details]

[0007] Next, the present invention will be described in detail. origin
Unlimited Layer Expansion with Expansion Lattice in Crystalline Three-layer Structure in Ming
Type clay minerals include trioctahedral and dioctahedral.
Doral and others belong to it, and are also called smectites.
The montmorillonite mineral group belongs to this. in this mineral group
Included are the following: Montmorillonite (OH)_FourSi₃(Al_3・34Mg_0.66)O₂₀・Na_0.66 Beidellite(OH) ₄ ( _Si6 ・ 34Al_{1・ 66})Al_{Four· 34}O₂₀・Na_{0・ 66} Nontronite(OH) ₄ ( _Si1 ・ 34Al_{0・ 66})Fe_FourO₂₀・Na_{0・ 66} Hectorite (OH)_FourSi₈(Mg_5・34Li_0.66)O₂₀・Na_0.66 Sabonite (OH)_Four(Si_7・34Al_0.66)Mg₆O₂₀・Na_0.66 In the present invention, an unlimited layer with an expansion lattice in this crystal three-layer structure
The expanded clay mineral has a diameter of 20 to 30 nm and a thickness of 0.5 nm.
Used as tablet-like (thin plate-like) particles of 5 to 2 nm
preferably. In other words, to make such a thin plate
It has transparency because it does not reflect irregularly like a spherical shape, and its
As a result, it is possible to increase the amount that can be added to the acrylic polymer solution.
can be done. The blending amount of the unlimited layer fat-expanded clay particles is
100 to 4 per 100 parts by weight of acrylic resin solid content
00 parts by weight, especially about 150 to 250 parts by weight
preferable. 1 per 100 parts by weight of acrylic resin solid content
If it is less than 00 weight, the antifogging property imparted to the synthetic resin film is
not sufficient, and when using 400 parts by weight or more, anti-fogging
improved, but the transparency of the synthetic resin film decreased.
I don't like it.

[Procedural amendment 4]

[Name of document to be amended] Description

[Correction target item name] 0008

[Correction method] Change

[Correction details]

The acrylic resin in the present invention includes acrylic acid ester and/or methacrylic acid ester and
acid group-containing vinyl monomers copolymerizable with these acrylates
and a copolymer with a hydroxyl group-containing vinyl monomer.
Acrylic acid ester monomers and methacrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate and ethyl methacrylate . Acid groups copolymerizable with these acrylates
Examples of vinyl-based monomers include acrylic acid, maleic acid,
Methacrylic acid, etc., as a hydroxyl group-containing vinyl monomer
is 2-hydroxy methacrylate and the like. these things
The ratio of mer is 1 to 10% by weight for the former and
about 5 to 30% by weight. other monomers
It may be added as a polymer component, and as its monomer
acrylamide, methacrylamide, N-methylol
acrylonitrile, styrene, vinyl acetate
and so on. Further , the acrylic resin used in the present invention must have a glass transition temperature Tg of 40C to 75C. That is, an acrylic resin having a Tg of less than 40°C has excellent adhesion but poor durability, and its antifogging property decreases with time.
It is not preferable because it has poor adhesion and adversely affects the anti-fogging property itself.

[Procedural amendment 5]

[Name of document to be amended] Description

[Correction target item name] 0009

[Correction method] Change

[Correction details]

[0009] The nonionic surfactant in the present invention is
It brings about effects such as improved dispersibility of the antifogging agent composition, improved wettability during surface treatment, and improved antifogging properties after treatment. Types of nonionic surfactants that can be used include polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, sugar esters, fluorine-based surfactants. agents, etc., but are not limited to these types of nonionic surfactants. The amount of the nonionic surfactant added is preferably 2 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the acrylic resin.
At 2 parts by weight or less, the wettability of the antifogging agent composition to the substrate,
The anti-fogging property is poor, and if it is 10 parts by weight or more, the strength of the coating film after forming the coating film is lowered, and as a result, the anti-fogging property cannot be maintained.
In addition, the mixing ratio of the nonionic surfactant and the dispersion medium is 1 part water.
It is preferable to use it in an amount of 0.5 parts by weight or less with respect to 00 parts by weight. Separation of liquid dispersion in the present invention
Although it is not particularly limited as a dispersion medium,
water or/and alcohol for ease and economic reasons
system solvents are preferred.

[Procedural amendment 6]

[Name of document to be amended] Description

[Correction target item name] 0015

[Correction method] Change

[Correction details]

Examples 1 to 9 A solution of the acrylic resin composition shown in Table 1, a 4% dispersion of hectorite and sugar esters as surfactants.
was used to prepare an antifogging agent composition in the ratio shown in Table 2, and the antifogging agent composition was applied to a polyethylene film treated with corona discharge at a solid content of 0.8 g/m ² by a spray coating method. It was dried at 90°C for 5 minutes. The polyethylene film obtained in this way is processed into a vinyl film as shown in FIG.
The anti-fogging property was investigated over time after stretching on a mouse . Table 2 shows the results. The 4% dispersion of hectorite in Table 2 was obtained by adding 4 parts by weight of tablet-like hectorite having a diameter of 20 to 30 nm and a thickness of 0.5 to 2 nm to 48 parts of isopropanol.
It is dispersed in a dispersion medium containing parts by weight and 48 parts by weight of water. 4% of other montmorillonite, beidellite, nontronite, hectorite, sabonite in Table 4
Dispersions are similarly prepared. The particle size of these mineral powders is 2
0 to 30 nm. Moreover, the solutions of AC-1 to 14 are products with a solid content of 50%. The antifogging test results were visually evaluated according to the following criteria. a Good anti-fogging property b Fairly good anti-fogging property c Poor anti-fogging property

[Procedural amendment 7]

[Name of document to be amended] Description

[Correction target item name] 0016

[Correction method] Change

[Correction details]

[0016]

[Table 2]

[Procedural amendment 8]

[Name of document to be amended] Description

[Correction target item name] 0019

[Correction method] Change

[Correction details]

Comparative Example 8 and Examples 10 to 14 AC-1 acrylic resin composition solution shown in Table 1 and Table 4
An antifogging agent composition was prepared from an unlimited layer expansion clay mineral dispersion and sugar esters with various crystal three-layer structures shown in , and antifogging and Transparency was measured. Table 4 shows the results. Incidentally, Comparative Example 8 is a case of using a talc dispersion.
be .

[Procedural amendment 9]

[Name of document to be amended] Description

[Correction target item name] 0020

[Correction method] Change

[Correction details]

[0020]

[Table 4]

──────────────────────────────────────────────────── ─── Continuation of the front page (51) ^Int.Cl.

Claims (4)

[Claims] [Claim 1] A crystalline three-layered, unlimited layer expansion type clay mineral, an acrylic resin having a glass transition temperature of 40°C to 75°C, and a nonionic surfactant as main components, water and/or An antifogging composition dispersed in a liquid dispersion comprising an alcoholic solvent. 2. The acrylic resin composition contains 1 to 10% by weight of an acid group-containing vinyl monomer and 5 to 3% by weight of a hydroxyl group-containing vinyl monomer.
An antifogging composition according to claim 1 at 0% by weight. 3. The unlimited layer expansion clay has a diameter of 20 to
2. The antifogging composition according to claim 1, which is in the form of a tablet having a thickness of 0.5 to 2 nm and a thickness of 30 nm. 4. An agricultural film obtained by applying the antifogging composition of claim 1 to a thermoplastic resin film.