JPH0335325B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel antistatic composition composed of a prepolymer, a reactive monomer, and a photopolymerization initiator, which is polymerized and cured by ultraviolet irradiation in the presence of a photopolymerization initiator. Synthetic resins, both thermoplastic and thermosetting resins, have good mechanical strength, heat resistance, electrical insulation, chemical resistance, lightness, moldability, machinability, etc., making them useful as metal substitutes, ceramics, and glass substitutes. It is used in large quantities as a raw material for fibers and as a substitute for natural fibers, and has become an almost indispensable element for maintaining human life. Although these synthetic resins have good electrical insulation properties, the synthetic resins themselves lack electrical conductivity and are charged with static electricity. Due to this static electricity charging, dust in the air adheres to the synthetic resin molded product, contaminating the surface and causing scratches. When these synthetic resins are used in weak electrical products or electronic components, static electricity may cause malfunctions. Furthermore, in tanks made of synthetic resin or painted with synthetic resin paint, sparks generated by charged static electricity may cause an explosion of vaporized or powdered substances, so synthetic resin products may antistatic treatment is required. Many methods have been used in the past to eliminate the various problems caused by static electricity on synthetic resin products. For example, (1) forming a thin film containing a surfactant on a synthetic resin molded product, (2) mixing and dispersing a surfactant into a synthetic resin, (3) mixing and dispersing a conductive metal into a synthetic resin, (4) Carbon black is mixed and dispersed in synthetic resin, but (1) the adhesion strength of the formed thin film is weak and the antistatic effect is attenuated.
(2) It takes a considerable amount of time for the antistatic effect to appear (this is because the antistatic effect occurs when the mixed and dispersed surfactant bleeds onto the surface of the synthetic resin molded product) , (3), (4) Mixing conductive substances causes drawbacks such as a decrease in the heat resistance and mechanical strength of the molded product, as well as a decrease in transparency and light transmittance, and there are many points for improvement. are seen here and there. Therefore, the object of the present invention is to provide a polymerized cured film that is free from the above-mentioned drawbacks, has excellent heat resistance, water resistance, and abrasion resistance, is transparent with high light transmittance, and has good antistatic properties. An object of the present invention is to provide an ultraviolet curable composition that can be obtained. The present invention, which achieves such objects, comprises at least one prepolymer [A] selected from the group consisting of urethane (meth)acrylate prepolymers, ester acrylate prepolymers, and epoxy acrylate prepolymers, and at least one prepolymer in the molecule. A compound [B] having at least one hydroxyl group and at least one unsaturated group, and a photopolymerization initiating compound having an absorption wavelength in the ultraviolet region, and at least one unsaturated group.
This is a mixture consisting of a photopolymerization initiator [C] in which atoms are substituted with halogen atoms, and relates to an ultraviolet curable antistatic composition that is polymerized and cured by ultraviolet irradiation to give an antistatic cured resin. . The polymerized cured film obtained from the composition of the present invention is an antistatic film with excellent heat resistance, water resistance, and abrasion resistance, and is a transparent film with high light transmittance. This was something that could not be achieved. The above three components [A], [A], and [C] are stirred and mixed at room temperature or heated, and applied to the surface of a synthetic resin molded product,
When exposed to ultraviolet light, it polymerizes and hardens to form a coating film. The prepolymer of component [A] imparts mechanical strength, flexibility, and impact resistance to the cured film, and also imparts antistatic properties. Specific examples include: Urethane (meth)acrylate prepolymer. This is the general formula It is a reaction product of polyol acrylate and polyvalent isocyanate represented by: Examples of polyvalent isocyanates include 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, diyuranate (Asahi Kasei Polyisocyanate), 2,4-diisocyanate, 1-
Examples include methylcyclohexane, 2,6-diisocyanate-1-methylcyclohexane, naphthylene-1,5-diisocyanate, lysine diisocyanate, and metaphenylene diisocyanate. These charging compositions and reaction conditions are
Details are given in specification No. 56-51976. The formula () shown later is a typical example. Ester acrylate prepolymer. An example of this is shown in the following equation (). For example, Aronix 8060 epoxy acrylate prepolymer manufactured by Toagosei Co., Ltd. An example of this is shown in the following equation (). For example, Kyoeisha Yushi 3002A Among the above prepolymers, in terms of antistatic performance, urethane (meth)acrylate prepolymers are most preferred, followed by ester acrylate prepolymers. The reactive monomer of component [B] linearly polymerizes itself and at the same time reacts with the prepomer of component [A] to form a crosslinked structure, which is useful for increasing the scratch resistance and mechanical strength of the cured film. The reactive monomer has at least one unsaturated group, at least one
A compound having both hydroxyl groups, specifically, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, ethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, Examples include neopentyl glycol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, and the like. When forming a cured film from a mixed solution of these reactive monomers, a prepolymer, and a photopolymerization initiator in which at least one atom is substituted with a halogen atom, in order to impart antistatic performance, this mixed solution must be In some cases, it may be necessary to heat the solution to the boiling point of the component with the lowest boiling point and irradiate it with ultraviolet rays, but depending on the reactive monomer, irradiation with ultraviolet rays may be necessary, whether applied at room temperature or at a heated temperature. In some cases, the cured coating produced by the above method exhibits antistatic properties. For example, when 2-hydroxyacrylate or polyethylene glycol monoacrylate is used, antistatic properties are imparted to the coating film after curing by ultraviolet irradiation, whether applied at room temperature or heated. However, when using 2-hydroxy methacrylate, the half-life of the cured film after application at room temperature and irradiation with ultraviolet rays is infinite, and antistatic performance is not imparted. Performance is given. Antistatic performance does not deteriorate by heating the mixed solution before application. Further, in order to impart hardness and scratch resistance to the polymerized and cured coating, the following crosslinking monomers may be added as necessary. For example, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate,
It is a compound having two (meth)acryloyl groups such as butanediol diacrylate, and the amount added is 5 to 15 parts by weight. The photopolymerization initiator as component [C] is a compound in which at least one hydrogen atom in its molecule is replaced with a halogen atom, and is an essential component for the development of antistatic properties of the cured film of the composition of the present invention. It is. Many compounds are known as photopolymerization initiators and sensitizers for photopolymerization initiators, and representative examples include benzophenone, acetophenone, benzoin, xanthone, anthraquinone, benzyl methyl ketal, etc., and their derivatives. . However, even with these photopolymerization initiators, the composition of the present invention cannot exhibit antistatic performance if the photopolymerization initiator does not have a halogen atom in its compound. Specifically, anthraquinone has no effect, 1-chloroanthraquinone exhibits antistatic performance, thioxanthone has no effect, and 2
- Chlorthioxanthone exhibits antistatic properties. In addition, by using a photopolymerization initiator substituted with a halogen atom such as hexachlorpara-xylene, 5-chloro-2-hydroxybenzophenone, or 3-chlorobenzophenone, the composition of the present invention can be prevented from charging. performance can be imparted. The amount of the photopolymerization initiator added in the composition of the present invention is preferably 1 to 2 phr. Also, the preferred blending ratio of components [A], [B], and [C] is [A] 5-50, [B] 95-50, and [C] 0.5-5.
(parts by weight). Next, examples will be shown. Parts are parts by weight. Example 1 Urethane acrylate prepolymer, 2-hydroxyethyl methacrylate, and 2 parts of a photopolymerization initiator were mixed and stirred in a glass container according to the composition shown in Table 1, left to stand, and then placed in an oil bath.
It was heated to 80°C. A transparent sheet of polymethyl methacrylate (2 mm x 100 mm x 200 mm) was added to this heated solution.
mm) was immersed for 30 seconds, pulled up at a speed of 200 mm/min, and irradiated with ultraviolet light for 45 seconds. The irradiation lamp
The distance from the sheet is 150 with a low pressure mercury lamp of 80W/cm.
It was warm in mm. The antistatic performance of the obtained sheet piece was measured and the results shown in Table 1 were obtained. In addition, in the composition of :=10 parts:90 parts, the same operation was carried out by changing the photopolymerization initiator as shown in Table 1, and the results shown in Table 1 were obtained. The results in Table 1 show sufficient antistatic performance. In this example, when the mixed solution was applied at room temperature without heating, the film polymerized and cured by ultraviolet irradiation had no antistatic effect and had an infinite half-life. Furthermore, when anthraquinone, thioxanthone, or benzophenone, which does not contain any halogen atoms, was used as a photopolymerization initiator, the half-life was infinite. The results are also shown in Table 1. The structural formula of a typical example of the urethane acrylate prepolymer is shown below.

【table】

[Formula] Example 2 Urethane acrylate prepolymer 10 parts, 2
- Mix 90 parts of bitroxyethyl acrylate and 2 parts of 1-chloro anthraquinone in a beaker, stir, and leave to stand. A transparent sheet of polymethyl methacrylate ((2 mm x 100 mm x 200 mm) is immersed in the solution for 1 minute. /min, and then irradiated with ultraviolet rays for 60 seconds to polymerize and harden the coating.The radiation source was a low-pressure mercury lamp of 80 W/cm, and the distance between the lamp and the specimen was 150 mm.The half-life of the specimen was In 2.4 seconds,
It was found that practically sufficient antistatic performance was imparted. The prepolymer has the following structural formula (), ()
It is a mixture of two compounds shown in . Example 3 10 parts of epoxy acrylate prepolymer of the above formula (), 90 parts of 2-hydroxyethyl acrylate
1 part of benzyl dimethyl ketal, and 0.5 part of 5-chloro-2-hydroxybenzophenone were placed in a beaker and mixed and stirred at room temperature. After standing still, a transparent sheet of polymethyl methacrylate was immersed in this solution for 30 seconds to form a 200 mm It was pulled up at a speed of /min. Subsequently, ultraviolet rays were irradiated for 45 seconds using an 80 W/cm low-pressure mercury lamp. The distance between the low pressure mercury lamp and the polymethyl methacrylate sheet was 50 mm. The antistatic performance of the obtained sheet piece has a half-life of 1.5 seconds and a surface resistance value of 5.
×10 ¹⁰ and the cured film was transparent, and no occurrence of clouding or other damage to the appearance of the sheet was observed. Instead of the above epoxy acrylate prepolymer, Aronix 8060 and three types of urethane acrylate prepolymers were used and mixed in the same ratio as above,
After forming a coating film at room temperature, it was irradiated with ultraviolet rays and its antistatic performance was measured. The results are summarized in Table 2.

[Table] In this example, a sheet coating film was formed after heating a mixed solution of a prepolymer, a reactive monomer, and a photopolymerization initiator, and a cured film was obtained by irradiating ultraviolet rays. Similar antistatic performance could be obtained. Example 4 After mixing and stirring the urethane acrylate prepolymer of formula () and 2-hydroxyethyl acrylate at a mixing ratio of 10:90, 30:70, and 50:50, respectively, 2 parts of benzyl dimethyl ketal and 3- Add and mix 0.5 parts of chlorobenzophenone, and use this mixture to form a coating film on a polymethyl methacrylate sheet at room temperature (by the dipping method) and irradiate it with ultraviolet rays using an 80W/cm low-pressure mercury lamp.
After irradiation for 30 seconds, the antistatic performance of the resulting cured film was measured in terms of half-life and surface resistance. 3rd result
Shown in the table.

[Table] Example 5 The mixing ratio of urethane acrylate prepolymer and polyethylene glycol monomethacrylate (2 moles of ethylene oxide) was 10:
The mixture was mixed and stirred at room temperature at a ratio of 90:30:70 and 50:50, and 5 parts of 1,6-hexanediol diacrylate, 2 parts of benzyl methyl ketal, and 1 part of 2-chlorothioxanthone were added to each mixture and mixed. Next, using this mixed solution, a coating film was formed on a polymethyl methacrylate sheet at room temperature (by dipping method, immersed in the mixed solution for 20 to 30 seconds and then pulled up at 20 cm/min), and exposed to ultraviolet light using an 80 W/cm low-pressure mercury lamp. was irradiated for 20 seconds to form a cured film, and the antistatic performance was measured. The results obtained are shown in Table 4. The distance between the low pressure mercury lamp and the sheet piece was 100 mm.

[Table] In Example 5, the substrate on which the cured film was formed was made of a polymethyl methacrylate sheet.
A similar cured film was formed using a transparent polystyrene sheet or AS molded by injection molding, and the antistatic performance was measured, and the same results as shown in Table 4 were obtained.

Claims (1)

[Scope of Claims] 1. At least one prepolymer [A] selected from the group consisting of urethane (meth)acrylate prepolymers, ester acrylate prepolymers, and epoxy acrylate prepolymers,
A compound [B] having at least one hydroxyl group and at least one unsaturated group in the molecule, and a photopolymerization initiating compound having an absorption wavelength in the ultraviolet region, in which at least one atom is substituted with a halogen atom. An ultraviolet curable antistatic composition which is polymerized and cured by ultraviolet irradiation to give an antistatic cured resin, comprising an initiator [C].