JPH03152181A - Cloud-preventive composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition forming a coating film having excellent hardness, resistance to water, etc., mainly on the surface of plastic molded article comprising a mono(meth)acrylate, urethane acrylate oligomer of respectively a specific polyhydric alcohol and a photopolymerization initiator. CONSTITUTION:(A) (i) 60-90 pts.wt. mono(meth)acrylate of a polyhydric alcohol expressed by formula I [X is expressed by formula II or formula III (R1 to R3 are H, methyl or ethyl; n4 is integer of 0-4); n1 and n2 are integer of 0-4; n3 is integer of 0-2] is mixed with (ii) 40-10 pts.wt. urethane acrylate oligomer expressed by formula IV [R4 is 2-4C alkylene; R5 is 2-15C aliphatic or aromatic diisocyanate; R6 is 2-6C (poly)alkylene diol or polyester diol; R7 is H or methyl; n5 is integer of 1-10]. Then, 100 pts.wt. resultant mixture (A) is mixed with 0.5-10 pts.wt. (B) photopolymerization initiator to afford the aimed composition of ultraviolet rays-curing type.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention mainly relates to an ultraviolet curable composition that forms an excellent antifogging film on the surface of a plastic molded article.

<Conventional technology> In general, polycarbonate resin, polymethyl methacrylate resin, polyvinyl chloride resin, cellulose ester resin, etc. are used to make helmet shields and ski goggles by taking advantage of their excellent transparency, lightness, ease of processing, impact resistance, etc. It is widely used in underwater goggles, industrial safety goggles, mirrors, various windows, etc. However, when the surface temperature of these plastic products falls below the dew point moisture level, moisture in the atmosphere becomes fine water droplets that condense on the surface, impairing visibility, which is a serious problem.

Various anti-fog processing methods have been proposed to solve this problem. Specifically, JP-A No. 58-25331 describes a method of coating and drying a composition comprising a water-soluble monomer copolymerized acrylic emulsion and a surfactant.
JP-A-58-103532 describes a method in which an alcohol solution of polyvinylpyrrolidone is applied and then heated and dried. With solutions of such hydrophilic polymers or solutions with surfactants added, the resulting coatings achieve initial antifogging properties, but are easily scratched due to poor hardness, and are not durable due to poor water resistance. inferior to sex.

JP-A-56-8258 describes a thermosetting composition containing a hydrolyzate of organoalkoxysilane, a polyhydric alcohol having an ethylene oxide chain, and a curing catalyst, and JP-A-60-223,885@ describes a thermosetting composition comprising polyvinyl alcohol, methylated melamine, a water-soluble acrylic resin, and a surfactant. In such a thermosetting antifogging composition, the hardness of the resulting film is improved due to crosslinking, and improvement in water resistance is also observed. However, since the hydrophilic functional groups are lost during the curing reaction, the antifogging properties deteriorate as the curing reaction progresses, and no material has been found that satisfies both antifogging properties and water resistance at the same time. Surfactants are often used in combination to supplement antifogging properties, but surfactants easily wash out in running water and have poor water resistance.

JP-A-62-15230 describes a method for producing an anti-fog plate in which a cellulose ester sheet or film is saponified with an alkali and then laminated with an adhesive. This method has provided the most stable heatproof sheet to date, with fairly excellent anti-fog properties and durability. However, this anti-fog sheet is quite expensive and furthermore cannot be heat bent when laminated to other plastics.

JP-A-61-76563 describes an ultraviolet curable composition comprising a specific multifunctional (meth)acrylate monolayer, a phosphate ester-based acrylate monomer, colloidal silica, and glycerin glycidyl ether acrylate. JP-A-61-118413 discloses alkyl hydantoin bisepoxide (meth)acrylic acid adduct, (meth)acrylate having an ethylene oxide chain, (meth)acrylic acid quaternary ammonium salt, and photopolymerization initiator. A UV-curable composition is described. Such ultraviolet curable heat protection compositions have improved antifogging properties and hardness compared to thermosetting compositions, probably because their hydrophilicity is not lost even through crosslinking reactions. However, it is still difficult to obtain practical antifogging properties and hardness. In addition, acrylate monomers with hydrophilic 10H groups or ether bonds are susceptible to incomplete curing due to exposure to oxygen during irradiation, so irradiation with ultraviolet rays is performed in an inert atmosphere that is specially shielded from air. However, it required irradiation for a long time, making it difficult to put it into practical use.

<Problems to be solved by the invention> In general, in antifogging processing, a film of a hydrophilic substance, that is, a substance with a small contact angle to water, is formed on the surface of the target plastic molded product, and condensed water droplets are formed on the surface of the plastic molded product. It is necessary to form the film into a water film as much as possible, and to absorb this water into the film. However, highly hydrophilic substances have low strength when wet with water, and if rubbed strongly, they easily break, swell in water, or even dissolve.

Water resistance can be improved by adding a component that imparts a crosslinked structure to this coating composition to make it three-dimensional, but conversely, antifogging properties are reduced. In this way, conventionally, anti-fog properties,
A film satisfying both hardness and water resistance was not obtained.

<Objective of the Invention> The object of the present invention is primarily to provide a composition that forms a film on the surface of a plastic molded article that is excellent in heat protection, hardness, and water resistance.

<Structure of the Invention> The present invention is based on (a) the following general formula (I) % formula % (I) [wherein, R3 is a hydrogen atom, a methyl group or an ethyl group, which may be the same or different),
n, , n2 and n are integers of 0 to 4, and n3 is an integer of O to 2. Mono(meth)acrylate of a polyhydric alcohol represented by (b) the following general formula (I) % formula %) [wherein R4 is an alkylene group having 2 to 4 carbon atoms, and Rs is an alkylene group having 2 to 15 carbon atoms] an aliphatic or aromatic diisocyanate residue, R6 is an alkylene diol residue having 2 to 6 carbon atoms, a polyalkylene diol residue, or an aliphatic dicarboxylic acid having 4 to 8 carbon atoms and a fullkylene diol having 2 to 6 carbon atoms; In the polyester diol residue obtained by the condensation reaction, R7 is a hydrogen atom or a methyl group, and n is an integer of 1 to 10. ] The urethane acrylate oligomer (C) consists of a photopolymerization initiator, and the amounts of (a) and (b) used are (a)/(b).
The weight ratio is 60/40 to 90/10, and the amount of (C) used is 0.5 per 100 parts by weight of the sum of (a) and (b).
~10 parts by weight of the antifogging composition.

Component (a) used in the present invention is a mono(meth)acrylate of a polyhydric alcohol represented by the general formula (I). Specifically, it is a mono(meth)acrylate of a polyhydric alcohol without an ethylene oxide chain added or a polyhydric alcohol with 1 to 4 ethylene oxide chains added, and is a component for imparting excellent hydrophilicity. be. In addition, component (a) is a relatively low viscosity liquid and also serves as a diluent. The number of ethylene oxide added should be 4 or less in terms of water resistance.

Specific examples of component (a) include ethylene glycol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, polyethylene glycol (200) mono(meth)acrylate, 1,3-propane Examples include diol mono(meth)acrylate, 1,4-butanediol mono(meth)acrylate, and glycerol mono(meth)acrylate.

Component (b) used in the present invention is a compound represented by the above formula (amount) and is referred to in the art as a urethane acrylate oligomer.

This product is usually made by adding diisocyanate to a diol such as alkylene diol, polyalkylene diol or polyester diol to perform the first urethanization reaction, and then adding a hydroxyl group-containing acrylate to perform the second stage urethanization reaction.
It is obtained by carrying out a step-by-step urethanization reaction. It can also be obtained by reacting a diisocyanate with a hydroxyl group-containing acrylate and then reacting with a diol.

Examples of diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polyethylene-propylene glycol, polytetramethylene glycol, etc. or ethylene glycol,
1.3-propanediol, 1,4-butanediol,
A polyester diol produced from an alkylene diol having 2 to 6 carbon atoms such as 1,6-hexanediol and an aliphatic dicarboxylic acid having 4 to 8 carbon atoms such as succinic acid or adipic acid is used.

As a diisocyanate, tolylene diisocyanate,
Aromatic diisocyanates such as 4.4-diphenylmethane diisocyanate, xylylene diisocyanate, or aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, methylene biscyclohexyl isocyanate, 2.4.41-limethylhexamethylene diisocyanate are used.

As the hydroxyl group-containing acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. are used.

The urethane acrylate oligomer obtained from the above components can have various molecular weights and viscosities depending on the molar ratio of diol, diisocyanate, and hydroxyl group-containing acrylate used, but the molecular weight is about 500 to 2000,
It is preferable that the viscosity is about 300 to 3000 voids (25°C). A low-viscosity oligomer with a viscosity lower than 300 voices (25°C) will lower the viscosity of the entire paint, and when applied by flow coating, the upper layer will be thinner, making oxygen damage more likely to occur in this thinner area. On the other hand, a highly viscous oligomer with a viscosity of more than 3000 voids (at 25° C.) becomes difficult to handle, and the hardness of the resulting film decreases.

Epoxy acrylate oligomers and ester acrylate oligomers are often used as reactive oligomers for UV-curable paints, but (b) of the present invention
If these oligomers are used in place of these components, the polymerization rate will be slow and the antifogging properties will also be reduced, making it impossible to obtain a practical product. However, these drawbacks can be overcome by using the oligomer of component (b) specified in the present invention. The reason for this is not clear, but the urethane acrylate oligomer used as component (b) in the present invention has four or more urethane bonds, and these urethane bonds have the effect of reducing oxygen damage and imparting hydrophilicity. considered to be a thing. Furthermore, when an acrylate or an initiator having an amino group is used, the antifogging properties of the coating material decrease over time.

However, even though the urethane acrylate oligomer used in the present invention also has nitrogen atoms, neither the resulting paint changes with time nor is its antifogging property deteriorated.

If the ratio of component (a) to component (b) is too low, sufficient antifogging properties will not be obtained, and if the ratio is too high, the hardness and water resistance of the resulting film will decrease. Ingredients and (b) The amount of ingredient used is (a)/
The weight ratio of (b) should be 60/40 to 90/No.

Component (C) used in the present invention is a commonly used photopolymerization initiator. Specific examples include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetophenone, p-dimethylaminoacetophenone, 2.2-dimethoxy-2-phenylacetophenone, 2.2-jethoxyacetophenone, p -tert
-butyltrichloroacetophenone, benzophenone,
4.4bisdimethylaminobenzophenone, 4.4'-
Bisdiethylaminobenzophenone, methyl-0-benzoylbenzoate, 2-chlorothioxanthone, 2.
4-diethylthioxanthone, anthraquinone, 1.2
-dihydroanthraquinone, 1-chloroanthraquinone, biacetyl, benzyl, tetramethylthiuram sulfide, phenyl-2-hydroxy-2-propyl ketone, p-isopropylphenyl-2-hydroxy-2-propyl ketone, p-hydroxyethoxyphenyl-2 −
Hydroxy-2-propyl ketone, 1-hydroxycyclohexylphenyl ketone, p-methylthiophenyl-
Examples include 2-morpholino-2-propylketone. In particular, α-hydroxy-alkylphenyl ketone type photopolymerization initiators are preferred because they have a fast polymerization rate and the resulting coating film has good performance.

The amount of component (C) used is 05 to 10f per 100 parts of the total amount of component (a) and component (b)! The mackerel of component (C) is ffi part, and 2 to 6-fold part is more preferable,
If it is less than 0.5 parts by weight, curing will be insufficient and tarakiness will remain, resulting in poor practicality. Moreover, if the amount is more than 103,111 parts, it is not suitable because it becomes colored and costs increase.

In addition to the components (a) to (C), the composition of the present invention includes:
Furthermore, small proportions of other UV-curable monomers and oligomers may be blended, and aids such as leveling agents, colorants, sensitizers, surfactants, storage stabilizers, heat stabilizers, light stabilizers, etc. There is no problem in using drugs together as needed.

The composition of the present invention is a relatively low viscosity liquid and can be coated, especially without the addition of a solvent. This is extremely advantageous since no special solvent drying step is required in the processing line. However, a solvent may be added for the purpose of further adjusting the film thickness, improving specularity, etc. Preferred solvents used in this case include alcohols such as ethanol, isopropanol, normal butanol, and isobutanol, and cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve.

The objects on which the film of the composition of the present invention is formed include sheets, injection molded products, and cast molded products of transparent resins such as polycarbonate resin, polymethyl methacrylate resin, polyvinyl chloride resin, cellulose ester resin, and polyallyl diglycol carbonate resin. etc. can be mentioned. In particular, polycarbonate resin is not only transparent but also has excellent impact resistance, so it is often used for various facepieces and windows.
The most suitable target for the composition of the present invention. Furthermore, heat protection can be imparted to glass and metal other than resin.

Any coating method may be employed to form a coating of the composition of the present invention on the molded article. For example, any method such as a spray method, dip method, 70-coat method, roll coat method, curtain flow method, spin code method, screen printing method, etc. may be used. If the thickness of the film is too thin, the anti-fog properties will be insufficient, and if it is too thick, the water resistance and adhesion will decrease, so
μ is preferred, and 10 to 20 μ is particularly preferred.

When painting, pretreatment can be performed in advance to improve the adhesion between the molded product and the coating, if necessary.

A cured film having antifogging properties can be formed by irradiating the composition of the present invention with ultraviolet rays after coating or after setting for several minutes.

A suitable ultraviolet irradiation device to be used is a high-pressure mercury lamp that irradiates ultraviolet rays with a wavelength of 250 to 400 nm. The standard irradiation conditions are preferably a lamp output of 80 to 120 w/01, a lamp distance of 5 to 30 α, and a conveyor speed of about 1 to 10 Trt/min. Furthermore, it can be cured by active energy rays other than ultraviolet irradiation, such as electron beams.

<Effects of the Invention> The composition of the present invention does not require a particular solvent drying step after being applied to transparent plastic sheets, injection molded products, etc., and can be cured by ultraviolet rays in the atmosphere.

In addition, as shown in the examples below, the obtained processed molded products were tested in breath tests and steam tests to show that the amount of saponified cellulose ester resin, which was conventionally considered to have an excellent antifogging amount, was 1.
It exhibits antifogging properties equal to or higher than Ti1, and has a hardness higher than that. In particular, when a coating formed from the composition of the present invention is applied to a polycarbonate molded article, its surface hardness is improved.

Furthermore, it has excellent water resistance, and its antifogging properties do not deteriorate even in a test in which it is immersed in running water for 14 hours.

As described above, the composition of the present invention can impart extremely excellent anti-fog properties to plastic molded products, so that it can be used in motorcycle helmet shields, ski goggles, underwater glasses, industrial glasses, etc., which require anti-fog properties. Various vehicle windows,
Useful for mirrors, etc. Furthermore, the antifogging plastic sheet coated with the composition of the present invention does not impair its performance or appearance even when subjected to heat bending.

<Example> The present invention will be explained in detail below with reference to Examples.

The UV irradiation conditions are lamp output 80w/t:m
The lamp distance was 1II115α, the conveyor speed was 1 m/min, and the standard irradiation was once, but if tarachy remained after one irradiation, the irradiation was repeated two or three times. Evaluations in Examples were performed in the following manner.

(I) Anti-fogging property (breath test) The number of times the sample surface becomes foggy by repeatedly blowing on it in an air-conditioned room at 25±2°C and 40±10% RH is measured.

Judgment x: Cloudy after one use.

Δ: Cloudy after 2 to 4 times.

No fogging after 0.25 times.

(2) Anti-fog property (steam test) 25±2℃, 40±10%R11 in an air conditioned room, 40±2℃
A sample of AOX 80JIm is placed on a 300 d tall beaker containing 300 ml of warm water maintained at 1° C., and the number of seconds until it begins to cloud is measured.

(3) Hardness (scratch resistance test) Rub the sample surface 20 times with #00GG steel wool.
Compare scratch resistance with untreated polycarbonate.

Judgment: ×: Stickiness remains and is very easily scratched.

Δ: Not sticky, but unprocessed poly Easily damaged than carbonate.

O: Same as unprocessed polycarbonate Or even harder to hurt.

(4) Water resistance (running water test) While running tap water at room temperature, 14 o'clock f! 18I
After soaking and taking out, leave in the air at 25±2℃ and 40±10%RH.
After adjusting the humidity above 8Rfli in the air, check for changes in appearance and conduct a steam test.

[Synthesis of urethane acrylate oligomer] (I) Polyethylene glycol with molecular weight 400 2009.2.4-
Tolylene diisocyanate 1309 was charged into a 1000 m flask and stirred at 40°C for 2 hours under a nitrogen stream.

The temperature was further raised to 65°C and stirred for 2 hours. Next, 70 g of droxyethyl acrylate, 0.29 g of dibutyltin laurate, and 0.39 g of hydroquinone monomethyl ether were added to this reaction solution, and the mixture was reacted at 65° C. for 4 hours while blowing air into the reaction solution to form a urethane acrylate oligomer. Obtained. Hereinafter, this will be abbreviated as 8-1.

(2) 186 g of 1,6-hexanediol, 849 diethylene glycol, 2309 adipine It, and 3 g of dibutyltin oxide were charged into a flask, and the internal temperature was raised to 220° C. while stirring under a nitrogen stream. then 1
After cooling to 00°C, moisture was removed under reduced pressure to obtain polyester diol.

250 g of this polyester diol and hexamethylene diisocyanate 1509 were placed in a 1000+d flask and stirred at 40°C for 2 hours under a nitrogen stream, and then the temperature was raised to 65°C and stirred for 2 hours. Next, 100 g of hydroxyethyl acrylate, 0□2 g of dibutyltin laurate, and 0.39 g of hydroquinone methyl ether were added to the reaction solution, and while blowing air into the reaction solution, 6
The reaction was carried out at 5°C for 4 hours to obtain a urethane acrylate oligomer. Hereinafter, this will be abbreviated as 8-2.

Example 1 [Preparation of coating composition] (a) Component: Hydroxyethyl acrylate 359, glycerol monomethacrylate 359 (b) Component: B-1309, (C) component: p-hydroxyethoxyphenyl-2-hydroxy- A coating composition was prepared by mixing 5.09 g of 2-propyl ketone (hereinafter abbreviated as C-1) and 30 g of isobutanol.

[Formation of film 1: The above film composition was coated on one side of a 2-foot thick polycarbonate sheet using a bar coater, and after setting at room temperature for 10 minutes, it was irradiated with ultraviolet rays once in the air to form a cured film. .

The film of the obtained polycarbonate coated sheet had a thickness of 15±5 μm, and the appearance, heat resistance, water resistance, and hardness were extremely good as shown in Table 1.

This coating showed adhesion of 100/10G in a cross-cut tape test. Further, when this coated sheet was heated at 160° C. for 10 minutes and subjected to pattern bending, no deterioration in appearance or antifogging properties was observed.

Comparative Examples 1 and 2 Table 1 shows the appearance, anti-fog properties, water resistance, and hardness of anti-fog sheet products (Boton AC manufactured by Toyo Kako Co., Ltd.) obtained by saponifying unprocessed polycarbonate sheets and cellulose triacetate sheets. Ta.

Examples 2 to 4 Example 1 was prepared using the coating composition used in Example 1 on a polymethyl methacrylate sheet (Acrylite, manufactured by Mitsubishi Rayon Co., Ltd.), a polyvinyl chloride sheet (Sunroid, manufactured by Naka Plastics Co., Ltd.), and a glass plate. A film was formed and evaluated according to the method, and the results are shown in Table 1.

(Margins below) Table 1 Examples 5 to 10 Shown in Table 2 instead of the (a) and (b) components used in Example 1 Other than using the (a) and (b) components listed in the table Created various film compositions in the same manner as in Example 1, formed and evaluated films in accordance with Example 1,
The results are shown in Table 2. In all cases, satisfactory appearance, antifogging properties, water resistance, and hardness were obtained with one UV irradiation. PEG-HA in the table: Polyethylene glycol monomethacrylate GLHA: Glycerol monomethacrylate HE
A: Hydroxyethyl acrylate TEG-H
^ Nitriethylene glycol monomethacrylate AU-2300: Urethane acrylate oligomer (Yuhi v-Atl-2300 manufactured by Mitsubishi Yuka Fine Chemicals Co., Ltd.).

Comparative Examples 3 to 9 Same as Example 1 except that the ingredients (a) and (b) shown in Table 3 were used in place of the ingredients (a) and (b) used in Example 1. Various coating compositions were prepared, and coatings were formed and evaluated according to Example 1. The results are shown in Table 3. In the table, HE^: and droxyethyl acrylate GLHA: glycerol monomethacrylate 2EtlA: 2-ethylhexyl acrylate P-5007: ester acrylate oligomer (
Photomer 5007) tl-2006 manufactured by Sannopco:
Ester acrylate oligomer (Yupimer S^-2006 manufactured by Mitsubishi Yuka Fine Chemical Co., Ltd.) P-3016: Epoxy acrylate oligomer (Photomer 3016 manufactured by Sannopco Co., Ltd.) V-540: Epoxy acrylate oligomer (Viscoat 540 manufactured by Osaka Organic Chemical Industry Co., Ltd.).

Examples 11 to 15 Various coating compositions were prepared in the same manner as in Example 1, except that component (C) listed in Table 4 was used in place of C-1 used as component (C) in Example 1. A film was formed and evaluated according to Example 1, and the binding is shown in Table 4. C-2 in the table: Phenyl-2-hydroxy-2-propyl ketone C-3: p-isopropylphenyl-2-hydroxy-
2-propyl ketone C-4: 1-hydroxycyclohexylphenyl ketone C-5 = benzyl C-6: 2,2-jethoxyacetophenone.

(Left below) Examples 16 and 17 and Comparative Examples 10 to 13 shown in Table 5
Various coating compositions were prepared according to Example 1 using the indicated number α for the components (a), (b), and (c), and a film was formed and evaluated. The results are shown in Table 5. It was shown to.

(Margin below)

Claims (1)

[Claims] (a) The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・
(I) [In the formula, , may be the same or different), n_1, n_2 and n_4 are integers from 0 to 4, n_3
is an integer from 0 to 2. ] Polyhydric alcohol mono(meth)acrylate, (b) General formula (II) below ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ Numerical formulas, chemical formulas, tables, etc. There is▼・・・・・・・・・
(II) [In the formula, R_4 is an alkylene group having 2 to 4 carbon atoms, R_5
is an aliphatic or aromatic diisocyanate residue having 2 to 15 carbon atoms, R_6 is an alkylene diol residue having 2 to 6 carbon atoms, a polyalkylene diol residue, or an aliphatic dicarboxylic acid having 4 to 8 carbon atoms, and an aliphatic dicarboxylic acid having 2 to 8 carbon atoms. Polyester diol residue obtained by condensation reaction with alkylene diol of 6, R_
7 is a hydrogen atom or a methyl group, and n_5 is an integer of 1 to 10. ] The urethane acrylate oligomer (c) consists of a photopolymerization initiator, and the usage amounts of (a) and (b) are (a)/(b).
The weight ratio is 60/40 to 90/10, and the amount of (c) used is 0.5 to 1 per 100 parts by weight of the sum of (a) and (b).
0 parts by weight of an antifogging composition.