JPH042603B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to curable resin compositions, particularly those referred to as photocurable resin compositions. A photocurable resin composition is a type of functional polymer whose molecular weight increases due to the reaction of acrylic groups incorporated in the resin composition upon absorption of light energy, and is a general name. The composition of the photocurable resin composition is a resin composition having as a basic component what is called an oligomer or polymer having a polymerizable acrylic group as one molecular constituent factor. The resin composition used as the basic component here requires activation of the polymerizable acrylic group by absorption of light as the first reaction condition for this type of resin due to its curing mechanism. In order to utilize this type of resin industrially, the polymerizable acrylic groups must sufficiently react to increase the molecular weight within a finite period of time, preferably as short as possible. Taking this point into consideration, the resin composition itself has poor light absorption efficiency, and the reaction rate of the polymerizable acrylic group is extremely slow, making it impossible to exhibit sufficient characteristics in the finite time that can be used industrially. Therefore, it cannot be put to practical use. Therefore, in reality, a photocurable resin composition contains a certain kind of substance in addition to a polymer containing a polymerizable acrylic group, and in this sense, a photocurable resin composition is a polymer containing a polymerizable acrylic group. will be called the basic component. Now, certain substances naturally have the effect of increasing the reaction rate of polymerizable acrylic groups and achieving high molecular weight within a finite industrially usable time, such as polymerization initiators or curing accelerators. A polymerization initiator containing what is called an agent has the effect of increasing light absorption efficiency and increasing the utilization efficiency of light energy from a light source for polymerization. Its basic function is that the polymerization initiator absorbs light with a wavelength longer than the wavelength of light that can activate the polymerizable acrylic group, and then propagates the light energy to the polymerizable acrylic group and activates the polymerizable acrylic group. It is about becoming. This function of the polymerization initiator makes it possible to efficiently utilize the light energy of the polymerization light source, increasing the reaction rate of the polymerizable acrylic group, and
High molecular weight can be achieved within a limited industrially available time. Examples of the curing accelerator include those that contain a polymerizable acrylic group in their structure and are simply referred to as reactive monomers in terms of molecular weight. The function of the curing accelerator is to promote the reaction between polymers containing polymerizable acrylic groups, and to adjust the curing rate and properties, or to adjust the viscosity of the photocurable resin composition. used for a purpose. As described above, the conventional photocurable resin composition is composed of (1) a polymer containing a polymeric acrylic group, (2) a polymerization initiator, and (3) a polymerization accelerator. Note that the polymerization accelerator is not always contained. Now, also in the photopolymerizable resin composition, the polymerization rate of the polymerizable acrylic group follows the generally accepted law of polymerization rate, that is, it is proportional to the concentration of the reactive component. Considering this point, as the reaction of the polymerizable acrylic group progresses and its concentration becomes diluted, the reaction rate will naturally decrease.
It is impossible to completely react the polymerizable acrylic groups within the industrially limited curing time. Therefore, under curing conditions, a certain amount of polymerizable acrylic groups remain in the photocurable resin composition, leading to various problems in properties.
In addition, various problems arise due to the characteristics of the polymer containing a polymerizable acrylic group and the inclusion of a polymerization initiator. For example, properties tend to change over time due to residual polymerizable acrylic groups. In the presence of a polymerization initiator and on a time scale under practical conditions, the reaction of the polymerizable acrylic group will proceed further, and the properties of the cured resin will change over time, causing the cured resin to become brittle. It causes various problems such as poor light resistance such as cracking and other problems such as poor adhesion and easy peeling. Further, in some cases, the addition of a polymerization initiator causes the polymerization initiator to become colored, which may limit its use. The main object of the present invention is to solve the drawbacks of these conventional photocurable resin compositions, that is, to provide a curable resin composition. That is, the present invention provides a polymer having a polymerizable unsaturated acrylic group selected from the group consisting of an acrylate ester oligomer, an acrylate polyester, an acrylate epoxy oligomer, an acrylate polyepoxy, an acrylate urethane oligomer, and an acrylate polyurethane, and an organic solvent-soluble polymer. This is a curable resin composition characterized by containing a styrene-containing acrylic thermoplastic resin and not containing a polymerization initiator. As is already clear, the feature of the present invention is that the reaction of the polymerizable acrylic group proceeds without adding a polymerization initiator. Therefore, in the curable resin composition according to the present invention, no polymerizable acrylic group reaction due to light absorption by the polymerization initiator is observed on a time scale under practical conditions, so changes in the properties of the cured resin product over time are not observed. It can be seen that it is easy to use because it is very small and stable, and it is also easy to design a curable resin composition. Also, since no polymerization initiator is added, the cured resin material is almost colorless and can be used in various fields very easily. In other words, it is ideal for transparent coating. Alternatively, in the case of coloring, the color of the coloring agent will develop as it is. Another feature is that excellent adhesion to metals, glass, etc. can be easily obtained. Taking advantage of this characteristic, it is also suitable for photocurable resin adhesives, protective films for vapor-deposited metals, exterior coatings for metals, protective films for metals, etc. In addition, properties can be improved in all aspects, such as improved water resistance and moisture resistance, and higher electrical resistance. As described above, the curable resin composition of the present invention does not require a polymerization initiator for curing, so it has excellent storage stability, and the properties of the cured resin material show very little change over time, resulting in improved stability and properties of various properties. , it is possible to add new characteristics. Examples of the polymer having a polymerizable unsaturated acrylic group used in the present invention include acrylate ester oligomer, acrylate polyester, acrylate epoxy oligomer, acrylate polyepoxy, acrylate urethane oligomer, and acrylate polyurethane. Suitable organic solvent-soluble styrene-containing acrylic thermoplastic resins include copolymers of styrene and acrylates such as metamethyl acrylate, methyl acrylate, butyl acrylate, or derivatives thereof, or copolymers of styrene and acrylate monomers. It is a copolymer with olefinic monomers such as ethylene, butylene or their derivatives. There is no particular restriction on the molecular weight as long as it is several thousand or more.
Select the constituent monomer components and molecular weight according to the desired properties. It should be noted that the addition of so-called reactive monomers as polymerization accelerators, such as hexamethylene, diacrylate, trimethylolpropane triacrylate, etc., as necessary, will not affect the properties. do not have. The following will be explained based on examples. Example 1 100 parts by weight of a polymer (product name: Acrybase CMZ-1, manufactured by Fujikura Kasei Co., Ltd.) as a styrene-containing acrylic thermoplastic resin and a polymer containing a polymerizable acrylic group (product name: Aronix M-8060, Toa Co., Ltd.) Curable resin composition () consisting of 100 parts by weight (synthetic)
For comparison, the reaction rate and stability under sunlight were measured for a curable resin composition (2) in which 2 parts by weight of 2-ethylanthraquinone was added as a polymerization initiator instead of the thermoplastic resin. These results are shown in FIGS. 1 and 2. FIG. 1 is a graph plotting the reaction rate of acrylic groups in the curable resin compositions against the irradiation time by irradiating the curable resin compositions () and () with a high-pressure mercury lamp. The curve is for the curable resin composition (); the curve is for the curable resin composition (). It is clear from FIG. 1 that the curable resin composition according to the present invention exhibits the reactivity of the polymerizable acrylic group even without containing a polymerization initiator, and the reaction rate is sufficiently low that the industrial limit is reached. It turns out that it's within the time. FIG. 2 is a graph showing stability under sunlight, where the straight line is for the curable resin composition (), and the straight line is for the curable resin composition (). Therefore, when a polymerization initiator is used, the reaction progresses further due to the absorption of light, but
In the composition based on the present invention, almost no reaction of the polymerizable acrylic group was observed, and it was found that the composition was stable. A comparison of some other properties is shown in the table below.

[Table] In the following examples, as in Example 1, curable resin compositions with good stability of properties were obtained. Example 2 Thermoplastic styrene-containing acrylic resin (product name: Acrybase CMZ-22, manufactured by Fujikura Kasei Co., Ltd.) 10 parts by weight of polymer containing a polymerizable acrylic group (product name: Uniday Ink V-5502, manufactured by Dainippon Ink)
100 parts by weight Example 3 Thermoplastic styrene-containing acrylic resin (product name: Lightac A-100, manufactured by Mitsui Toatsu) 20 parts by weight Polymer containing a polymerizable acrylic group (product name: Sonne CK-8, manufactured by Kansai Paint) ) 100 parts by weight Example 4 Thermoplastic styrene-containing acrylic resin (product name: Dialex HF-55, manufactured by Mitsubishi Monsanto)
40 parts by weight Polymer containing polymerizable acrylic group (Product name:
MUVC-Wo-4, manufactured by Dainichiseika) 100 parts by weight

[Brief explanation of drawings]

FIG. 1 is a graph showing the reaction rate of acrylic groups in a curable resin composition. FIG. 2 is a graph showing the stability of the curable resin composition under sunlight.

Claims (1)

[Claims] 1 A polymer having a polymerizable unsaturated acrylic group selected from the group consisting of an acrylate ester oligomer, an acrylate polyester, an acrylate epoxy oligomer, an acrylate polyepoxy, an acrylate urethane oligomer, and an acrylate polyurethane, and an organic solvent-soluble styrene-containing acrylic thermal A curable resin composition comprising a plastic resin and no polymerization initiator.