JP2010072370A - Optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide can adjust easily a difference of a refractive index between a core and a clad. <P>SOLUTION: This optical waveguide includes a core part for propagating light, and a clad part having a lower refractive index than the core part and positioned in contact with the core part. The core part is formed of a hardened material of an active radiation hardening polymer having a maleimide group, and a low molecular weight compound having a higher refractive index than the hardened material or a photoreaction residue of a polymer of the low molecular weight compound and the maleimide group exists in the hardened material of the active radiation hardening polymer having the maleimide group forming the core part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical waveguide including a core and a clad having a lower refractive index than that of the core and surrounding the core.

  Data transfer using optical frequency carriers generated from light sources such as lasers or light emitting diodes is becoming increasingly important. One means for guiding such an optical frequency carrier wave from one point to another is an optical waveguide. The optical waveguide includes a first medium (core) that is substantially transparent to light of an optical frequency carrier wave, and a second medium (cladding) having a lower refractive index than the first medium. The first medium is surrounded by the second medium or encapsulated inside the second medium. The light introduced from the end of the first medium undergoes total internal reflection at the boundary with the second medium, and is thereby guided along the axis of the first medium. Often used as the first medium is a glass formed into an elongated fiber shape. However, glass optical fiber is convenient for long-distance data transport, but it is not preferable for complicated high-density circuits because circuit density causes problems in use and costs. . On the other hand, polymer materials are promising because they can create components that are reasonably cost, reliable, passive and practical, yet perform the functions required for integrated optics. .

  Therefore, in recent years, research for forming an optical waveguide from a polymer material using a photocuring method has been actively conducted. Optical waveguides are particularly required to have good optical properties in the wavelength region (around 850 nm) used for optical wiring, and solder heat resistance for products that require mounting processes for electrical or electronic components. The In particular, in recent years, there has been a demand for solder lead-free due to environmental conservation considerations, and since the solder reflow temperature has increased, heat resistance that can maintain the shaped shape even at high temperatures has become necessary.

  For example, a copolymer of maleimide and norbornene, which is excellent in heat resistance, etching resistance, adhesiveness, and the like, has been studied as an optical material (Patent Document 1, Patent Document 2, and Patent Document 3).

JP 2001-200018 A (Claims) JP 11-228536 A (Claims) JP-A-11-322855 (Claims)

  In such a conventional optical waveguide, the refractive index of the core and the clad depends on the type of polymer for core formation and the type of polymer for clad formation. If the difference in refractive index is not sufficient, the polymer type itself must be changed to another polymer to adjust the difference in refractive index. However, there is a problem that even if the type of polymer itself is changed to another polymer, the performance other than the refractive index is changed, so that the change cannot be made.

  By the way, if the cured polymer of the core-forming polymer and the cured polymer of the cladding-forming polymer are made of a polymer having the same structure or a similar structure, the linear expansion coefficients of the core and the cladding are almost equal. For the sake of illustration, since stress is less likely to occur between the core and the clad, it is less likely to cause cracks due to curing shrinkage, and to have a similar chemical structure, it has the advantage of excellent adhesion or adhesion. In order to have a sufficient difference in refractive index, the cured polymer of the core forming polymer and the cured polymer of the cladding forming polymer are cured with the same structure or a similar structure. I couldn't make it.

  Accordingly, an object of the present invention is to provide an optical waveguide in which a difference in refractive index between a core and a clad can be easily adjusted. Furthermore, another object of the present invention is to provide an optical waveguide in which a core and a clad are formed by using a cured product of a polymer having the same structure or a similar structure.

  As a result of intensive studies to achieve the above object, the inventors of the present invention formed either the core or the clad or both of them with a cured product of an active radiation curable polymer having a maleimide group, and the maleimide group A low molecular weight compound having a refractive index different from that of the cured product is photoreacted, and a low molecular weight compound having a refractive index different from that of the cured product or a polymer of the low molecular weight compound and a maleimide group in the cured product. The presence of the photoreactive residue (1) facilitates the adjustment of the difference in refractive index between the core and the clad, and (2) the core and the clad have the same structure or a similar structure. The present invention has been completed by finding out that the film can be formed by using.

That is, the present invention (1) is an optical waveguide having a core part for propagating light and a clad part in contact with the core part and having a refractive index lower than that of the core part,
The core part is formed of a cured product of an actinic radiation curable polymer having a maleimide group,
In the cured product of the active radiation curable polymer having a maleimide group forming the core part, a low molecular weight compound having a higher refractive index than the cured product, or a photoreactive residue of a polymer of the low molecular weight compound and a maleimide group The present invention provides an optical waveguide characterized by the presence of.

Further, the present invention (2) is an optical waveguide having a core part for propagating light and a clad part in contact with the core part and having a refractive index lower than that of the core part,
The cladding is formed of a cured product of an actinic radiation curable polymer having a maleimide group,
In the cured product of the actinic radiation curable polymer having a maleimide group forming the cladding part, a low molecular weight compound having a refractive index lower than that of the cured product, or a photoreactive residue of the polymer of the low molecular weight compound and the maleimide group The present invention provides an optical waveguide characterized by the presence of.

  ADVANTAGE OF THE INVENTION According to this invention, the optical waveguide with easy adjustment of the difference of the refractive index between a core and a clad can be provided. Furthermore, it is possible to provide an optical waveguide in which a core and a clad are formed using polymers having the same structure or a similar structure.

  The optical waveguide of the present invention will be described below. The active radiation curable polymer having a maleimide group according to the optical waveguide of the present invention is also referred to as an active radiation curable polymer (b). The active radiation curable polymer (b) is a low molecular weight compound having a refractive index higher than that of the cured product, and reacts with the maleimide group of the active radiation curable polymer (b) to thereby react with the active radiation curable polymer. The low molecular weight compound having a higher refractive index than the cured product of (b) or a compound that gives a photoreactive residue between a polymer of the low molecular weight compound and a maleimide group is also referred to as a low molecular weight compound (a1). Further, the active radiation curable polymer (b) is a low molecular weight compound having a refractive index lower than that of the cured product, and is photoreacted with the maleimide group of the active radiation curable polymer (b), thereby the active radiation curable polymer. The low molecular weight compound having a refractive index lower than that of the cured product of (b) or a compound that gives a photoreactive residue between a polymer of the low molecular weight compound and a maleimide group is also referred to as a low molecular weight compound (a2). That is, the low molecular weight compound (a1) acts as a compound that increases the refractive index of the cured product of the actinic radiation curable polymer (b) by reacting with the maleimide group, while the low molecular weight compound (a2) ) Acts as a compound that lowers the refractive index of the cured product of the active radiation curable polymer (b) by reacting with the maleimide group. The low molecular weight compounds (a1) and (a2) are collectively referred to as a low molecular weight compound (a).

The optical waveguide of the first embodiment of the present invention (hereinafter also referred to as the optical waveguide (1) of the present invention) is in contact with the core portion for propagating light, and has a refractive index from the core portion. An optical waveguide having a low cladding portion,
The core is formed of a cured product of the actinic radiation curable polymer (b);
In the cured product of the actinic radiation curable polymer (b) forming the core part, a low molecular weight compound (a1) having a higher refractive index than the cured product or a polymer of the low molecular weight compound (a1) and a maleimide group It is an optical waveguide in which a photoreactive residue exists.

  In the optical waveguide (1) of the present invention, “the refractive index is higher than that of the cured product” means that the active radiation curable polymer (b) is cured without containing the low molecular weight compound (a). This means that the refractive index is higher than the cured product obtained.

  The optical waveguide (1) of the present invention is also described, for example, as a first method example (hereinafter, a method example (1) of manufacturing the optical waveguide of the present invention) for manufacturing the optical waveguide of the present invention shown below. ) Or a second method example for manufacturing the optical waveguide of the present invention (hereinafter also referred to as a method example (2) for manufacturing the optical waveguide of the present invention).

  In the method example (1) for producing the optical waveguide of the present invention, a polymer layer for forming a core portion that is cured by irradiation with actinic radiation is formed on a lower clad (core layer forming polymer layer forming step). Then, the polymer layer for forming the core portion is masked and irradiated with actinic radiation, the exposed portion is cured (core portion curing step), and then development is performed to remove the unexposed portion with a developer. Only the core part is formed on the clad (development process), and then a polymer layer for forming the core-encapsulating upper layer cladding is formed on the lower-layer clad and the core part (polymer for forming the core-encapsulating upper layer cladding) Layer forming step), and then irradiating the polymer layer for forming the core encapsulating upper layer clad with active radiation to cure the polymer for forming the core encapsulating upper layer cladding (hardening the core encapsulating upper layer cladding) The step), a method of obtaining an optical waveguide.

  The process of manufacturing the optical waveguide (1) of the present invention using the method example (1) of manufacturing the optical waveguide of the present invention will be described with reference to FIGS. FIGS. 1-7 is typical sectional drawing which shows the form example of the process of manufacturing the optical waveguide (1) of this invention using the example (1) of manufacturing the optical waveguide of this invention. In FIG. 1 to FIG. 7, the front and back direction of the paper is the light transfer direction of the optical frequency carrier wave.

  First, as shown in FIG. 1, the actinic radiation curable polymer (b) layer 2 (hereinafter referred to as active) formed of the actinic radiation curable polymer (b) and containing the low molecular weight compound (a1). A radiation curable polymer (b) layer 2 is also described) is formed on the lower cladding 1. At this time, as the lower cladding 1, one having a refractive index lower than that of a core portion 7 described later is used. In addition, the low molecular weight compound (a1) contained in the active radiation curable polymer (b) layer 2 is the active radiation curable polymer (b) forming the active radiation curable polymer (b) layer 2. It is a low molecular weight compound having a higher refractive index than the cured product, and a compound that reacts with a maleimide group by irradiation with actinic radiation.

  Next, as shown in FIG. 2, the surface of the active radiation curable polymer (b) layer 2 is masked with a photomask 3 and, for example, ultraviolet rays 4 are irradiated. Thereby, as shown in FIG. 3, in the active radiation curable polymer (b) layer 2, the exposed portion 5 irradiated with the ultraviolet rays 4 becomes a cured product of the active radiation curable polymer (b). The unexposed portion 6 that has not been irradiated with the ultraviolet ray 4 remains the active radiation curable polymer (b). Moreover, in this exposure part 5, by irradiation with ultraviolet rays 4, the low molecular weight compound (a1) reacts with the maleimide group of the active radiation curable polymer (b). In the cured product of the polymer (b), a photoreactive residue between the low molecular weight compound (a1) having a refractive index higher than that of the cured product and a maleimide group is present. Depending on the type of the low molecular weight compound (a1), a polymerization reaction between the low molecular weight compounds (a1) may also occur by irradiation with actinic radiation. When the polymerization reaction between the low molecular weight compounds (a1) also occurs, two or more low molecular weight compounds (a1) are polymerized in the exposed portion 5 during the irradiation of active radiation in the core portion curing step. Thus, a polymer of the low molecular weight compound (a1) is produced, and a reaction between the produced polymer of the low molecular weight compound (a1) and a maleimide group also occurs. Therefore, in the cured product of the actinic radiation curable polymer (b) of the exposed portion 5, the low molecular weight compound (a1) having a higher refractive index than the cured product or a polymer of the low molecular weight compound (a1) and There will be a photoreactive residue with the maleimide group.

  Next, in the actinic radiation curable polymer (b) layer 2, the unexposed portion 6 that has not been cured is removed with a developer, and the core portion 7 is formed on the lower cladding 1 as shown in FIG. Only form.

  Next, as shown in FIG. 5, the core portion encapsulating upper layer clad forming polymer layer 8 is formed using the core portion encapsulating upper layer clad forming polymer so as to surround the core portion 7. At this time, the core encapsulating upper layer clad forming polymer for forming the core encapsulating upper layer clad forming polymer layer 8 has a refractive index of a cured product lower than the refractive index of the core 7 when cured. Is used.

  Next, the core encapsulating clad forming polymer layer 8 is irradiated with ultraviolet rays to cure the core encapsulating clad forming polymer, thereby forming the core encapsulating upper cladding 9 (FIG. 6). As a result, the optical waveguide 10 in which the core portion is surrounded by the cladding portion is formed.

  As shown in FIG. 7, the core-encapsulating upper layer cladding 9 has a portion formed on the core portion 7 and a portion formed beside the core portion 7. As shown in FIGS. 5 and 6, the portion formed on the core portion 7 and the portion formed on the side of the core portion 7 are formed at the same time. In the embodiment shown in FIG. 6, there is no boundary between the two, but for convenience of explanation, it is formed on the core portion 7 of the core portion encapsulating upper layer clad 9 as shown by the dotted line in FIG. This portion is referred to as an upper clad portion 12, and the portion formed beside the core portion 7 and sandwiched between the lower clad 1 and the upper clad portion 12 is referred to as an intermediate clad portion 11.

  In the optical waveguide 10, in the core portion 7, the low molecular weight compound (a1) or the low molecular weight compound (a1) that acts as a compound that increases the refractive index of the cured product of the active radiation curable polymer (b). ) And a maleimide group are photoreactive residues produced by photoreaction. On the other hand, the lower clad 1, the intermediate clad portion 11, and the upper clad portion 12 are formed of a material having a refractive index lower than that of the core portion 7. Therefore, since the core portion 7 is surrounded by the lower layer cladding 1, the intermediate layer cladding portion 11, and the upper layer cladding portion 12 having a refractive index lower than that of the core portion 7, the optical waveguide 10 has an optical frequency. It functions as an optical waveguide that transports the light of the carrier wave.

  In the method (2) for producing the optical waveguide of the present invention, the active radiation is formed on the lower clad by the active radiation curable polymer (b) and contains the low molecular weight compound (a). An actinic radiation curable polymer layer producing step for producing a curable polymer (b) layer; a first irradiating step of irradiating actinic radiation with a mask having a pattern shape on the actinic radiation curable polymer (b) layer; A low molecular weight compound volatilization step for volatilizing the low molecular weight compound (a) from an unexposed portion of the actinic radiation curable polymer (b) layer that has not been irradiated with actinic radiation under heating or reduced pressure; A second irradiation step of irradiating the actinic radiation curable polymer (b) layer with actinic radiation to obtain a cured product layer of the actinic radiation curable polymer (b); and the actinic radiation curable polymer (b). Curing On the layer, a method of obtaining the upper cladding layer producing step of producing an upper clad, the optical waveguides do.

  The process of manufacturing the optical waveguide (1) of the present invention using the method example (2) of manufacturing the optical waveguide of the present invention will be described with reference to FIGS. FIG. 8 to FIG. 13 are schematic cross-sectional views of a form example of a process of manufacturing the optical waveguide (1) of the present invention using the method example (2) of manufacturing the optical waveguide of the present invention. In FIGS. 8 to 13, the front and back direction of the paper is the light transfer direction of the optical frequency carrier wave.

  First, as shown in FIG. 8, the active radiation curable polymer (b) layer 22 (hereinafter referred to as active) formed of the active radiation curable polymer (b) and containing the low molecular weight compound (a1). A radiation curable polymer (b) layer 22 is also formed on the lower cladding 21 (active radiation curable polymer layer preparation step). At this time, the lower clad 21 has a refractive index lower than that of a core portion 29 described later. In addition, the low molecular weight compound (a1) contained in the active radiation curable polymer (b) layer 22 is the active radiation curable polymer (b) forming the active radiation curable polymer (b) layer 22. It is a low molecular weight compound having a higher refractive index than a cured product, and a compound that reacts with a maleimide group when irradiated with actinic radiation.

  Next, as shown in FIG. 9, the surface of the actinic radiation curable polymer (b) layer 22 is masked with a photomask 23 and, for example, irradiated with ultraviolet rays 24 (first irradiation step). As a result, as shown in FIG. 10, the active radiation curable polymer (b) layer 22 is irradiated with the ultraviolet ray 24, that is, the exposed portion 26, and the portion not irradiated with the ultraviolet ray 24, that is, Thus, the unexposed portion 25 exists. And in this exposure part 26, since the reaction of a part of maleimide groups of this actinic radiation curable polymer (b) and reaction of this low molecular weight compound (a1) and a maleimide group occur, this low molecular weight compound (a1 ) Reacts with the maleimide group to form a photoreactive residue between the low molecular weight compound (a1) and the maleimide group, thereby binding to the active radiation curable polymer (b) layer 22 and being firmly held. The On the other hand, in the unexposed portion 25, the low molecular weight compound (a1) is present without being bonded to the actinic radiation curable polymer (b) layer 22.

  In the first irradiation step, depending on the type of the low molecular weight compound (a1), a polymerization reaction between the low molecular weight compounds (a1) occurs due to irradiation with actinic radiation. When the polymerization reaction of the low molecular weight compounds (a1) also occurs, in the exposed portion 26, two or more low molecular weight compounds (a1) are polymerized during the first irradiation step, and the low molecular weight compounds (a1) are polymerized. A polymer of the molecular weight compound (a1) is produced, and a photoreaction of the produced polymer of the low molecular weight compound (a1) and the maleimide group also occurs. Therefore, in the cured product of the actinic radiation curable polymer (b) of the exposed portion 26, the low molecular weight compound (a1) having a higher refractive index than the cured product or a polymer of the low molecular weight compound (a1) and There will be a photoreactive residue with the maleimide group.

  Next, the actinic radiation curable polymer (b) layer 22 is heated together with the lower clad 21 or placed under reduced pressure to volatilize the low molecular weight compound (a1) from the unexposed portion 25 (low molecular weight compound). Volatilization process). As a result, the unexposed portion 25 becomes an unexposed portion 27 from which the low molecular weight compound (a1) has been volatilized and removed (hereinafter also referred to as a low molecular weight compound removed unexposed portion 27) (FIG. 11).

  Next, as shown in FIG. 12, the entire actinic radiation curable polymer (b) layer 22 is irradiated with ultraviolet rays 24 to irradiate all the actinic radiation curable polymer (b) layer 22 with the actinic radiation curable polymer (b) layer 22. (B) is cured (second irradiation step). Accordingly, the actinic radiation curable polymer (b) layer 22 becomes a cured product layer 31 of the actinic radiation curable polymer (b), and at this time, the exposed portion 26 becomes the core portion 29, and The molecular weight compound-removed unexposed portion 27 becomes the intermediate layer cladding portion 28.

  Next, an upper clad 30 made of a material having a refractive index lower than that of the core portion 29 is formed on the intermediate layer clad portion 28 and the core portion 29 to obtain the optical waveguide 40.

  In the optical waveguide 40, the core portion 29 has the low molecular weight compound (a1) or the low molecular weight compound (a1) that acts as a compound that increases the refractive index of the cured product of the active radiation curable polymer (b). There exists a photoreactive residue of a polymer of On the other hand, the intermediate layer clad portion 28 is composed only of a cured product of the actinic radiation curable polymer (b), or the low molecular weight compound (a1) or the low molecular weight compound is contained in the intermediate layer clad portion 28. Even if there is a photoreactive residue between the polymer (a1) and the maleimide group, the amount of the refractive index of the core portion 29 is smaller than that of the core portion 29. Higher than the rate. The lower clad 21 and the upper clad 30 are formed of a material having a refractive index lower than that of the core portion 29. Therefore, the core portion 29 is surrounded by the lower clad 21, the intermediate clad portion 28, and the upper clad 30, which have a lower refractive index than the core portion 29. It functions as an optical waveguide that transports light.

  In the optical waveguide (1) of the present invention, the core portion is formed of a cured product of the actinic radiation curable polymer (b), and the actinic radiation curable polymer (b) that forms the core portion. In the cured product, a low molecular weight compound (a1) having a refractive index higher than that of the cured product of the active radiation curable polymer (b) forming the core portion, or a polymer and a maleimide group of the low molecular weight compound (a1) There are photoreactive residues. And in the optical waveguide (1) of this invention, this clad part is suitably selected so that a refractive index may become lower than this core part.

  Table 1 shows an example of an embodiment manufactured by the method example (1) for manufacturing the optical waveguide of the present invention out of the optical waveguide (1) of the present invention. The embodiment shown in Table 1 is the same as the embodiment shown in FIGS. 1 to 6 in order to form the lower cladding 1 and the core inner sealing upper cladding 9 (the intermediate cladding 11 and the upper cladding 12). By selecting various polymers as the polymer, using the actinic radiation curable polymer (b), or using the actinic radiation curable polymer (b) containing the low molecular weight compound (a2) Manufactured.

  In Table 1, (A1) is formed by a cured product of the actinic radiation curable polymer (b), and the low molecular weight compound (a1) or the low molecular weight compound (a1) is contained in the cured product. This is a material in which a photoreactive residue of a polymer of the above and a maleimide group exists. (B1) is formed of a material other than the cured product of the actinic radiation curable polymer (b) and has a refractive index lower than that of the core portion. (C1) is formed of a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a2) or a polymer of the low molecular weight compound (a2) It is a material in which a photoreactive residue with a maleimide group exists. (D1) is formed by a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) Neither the photoreactive residue with the maleimide group nor the photoreactive residue between the low molecular weight compound (a2) or the polymer of the low molecular weight compound (a2) and the maleimide group is present. In addition, (D1) is obtained by containing the low molecular weight compound (a2) in the actinic radiation curable polymer (b) and photocuring it. When either or both of the lower clad and the core-encapsulating upper-layer clad are formed of a cured product of the actinic radiation curable polymer (b), they form the core The cured product of the actinic radiation curable polymer (b) having a structure different from that of the actinic radiation curable polymer (b) having the same structure as the actinic radiation curable polymer (b) Also good.

  Of the optical waveguide (1) of the present invention, the embodiment manufactured by the method example (1) for manufacturing the optical waveguide of the present invention is not limited to the one shown in Table 1, but for example, The lower clad or the core encapsulating upper clad is formed of a cured product of the active radiation curable polymer (b), and the low molecular weight compound (a1) or the low molecular weight compound is contained in the cured product. Although the photoreactive residue of the polymer of (a1) and the maleimide group exists, since the abundance is smaller than that of (A1), a material having a refractive index lower than that of the core part is also included. .

  Moreover, Table 2 shows an example of the embodiment manufactured by the method example (2) for manufacturing the optical waveguide of the present invention out of the optical waveguide (1) of the present invention. In the embodiment shown in Table 2, in the embodiment shown in FIGS. 8 to 13, various polymers can be selected as the polymer for forming the lower clad 21 and the upper clad 30, and the active radiation curing is performed. It can be produced by using a functional polymer (b) or using the actinic radiation curable polymer (b) containing the low molecular weight compound (a1).

  In Table 2, (A2) is formed by a cured product of the actinic radiation curable polymer (b), and the low molecular weight compound (a1) or the low molecular weight compound (a1) is contained in the cured product. This is a material in which a photoreactive residue of a polymer of the above and a maleimide group exists. (B2) is formed of a material other than the cured product of the actinic radiation curable polymer (b) and has a refractive index lower than that of the core portion. (C2) is formed by a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a2) or a polymer of the low molecular weight compound (a2) It is a material in which a photoreactive residue with a maleimide group exists. (D2) is formed of a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) Neither the photoreactive residue with the maleimide group nor the photoreactive residue between the low molecular weight compound (a2) or the polymer of the low molecular weight compound (a2) and the maleimide group is present. (D2) can be obtained by allowing the actinic radiation curable polymer (b) to contain the low molecular weight compound (a2) and photocuring it. Further, when either or both of the lower clad and the upper clad are formed of a cured product of the active radiation curable polymer (b), they are the active forming the core part. It may be a cured product of the active radiation curable polymer (b) having the same structure as the radiation curable polymer (b) or a cured product of the active radiation curable polymer (b) having a different structure.

  Of the optical waveguide (1) of the present invention, the embodiment manufactured by the method example (2) for manufacturing the optical waveguide of the present invention is not limited to the one shown in Table 2, and for example, Since a small amount of the low molecular weight compound (a1) remains during the low molecular weight compound volatilization step, the intermediate clad portion is formed of a cured product of the actinic radiation curable polymer (b). And in this hardened | cured material, although the photoreaction residue of the polymer of this low molecular weight compound (a1) or this low molecular weight compound (a1) and a maleimide group exists, it exists from (A2). Since the amount is small, a material having a refractive index lower than that of the core portion is also included.

  In the optical waveguide (1) of the present invention, the core portion and the clad portion are formed of a cured product of the actinic radiation curable polymer (b). Since the linear expansion coefficient of the part shows almost the same value, it is difficult for stress to occur between the core part and the clad part, so that cracking due to hardening shrinkage hardly occurs and a similar chemical structure is taken. Therefore, it is preferable in that it has an advantage of being excellent in adhesion or adhesive force, and is a cured product of the active radiation curable polymer (b) that forms the core part, and the part that forms all or part of the cladding part. The cured product of the actinic radiation curable polymer (b) is particularly preferably a cured product of the actinic radiation curable polymer having the same maleimide group. For example, when the optical waveguide (1) of the present invention is the optical waveguide manufactured by the method example (1) for manufacturing the optical waveguide of the present invention, the core portion and at least the core portion encapsulating upper layer cladding are Preferably, it is formed of a cured product of the actinic radiation curable polymer (b), and a cured product of the actinic radiation curable polymer (b) that forms the core portion, and at least the core-encapsulated upper layer cladding is formed. The cured product of the actinic radiation curable polymer (b) is particularly preferably the same cured product of the actinic radiation curable polymer (b). When the optical waveguide (1) of the present invention is the optical waveguide manufactured by the method example (2) for manufacturing the optical waveguide of the present invention, the core portion and the intermediate layer cladding portion have the same structure. Of the actinic radiation curable polymer (b). In the optical waveguide (1) of the present invention, it is preferable that the core part and the clad part are all formed of a cured product of the active radiation curable polymer (b). It is particularly preferable that all of the parts are formed of a cured product of the actinic radiation curable polymer (b) having the same structure.

The optical waveguide of the second aspect of the present invention (hereinafter also referred to as the optical waveguide (2) of the present invention) is in contact with the core portion for propagating light, and has a refractive index from the core portion. An optical waveguide having a low cladding portion,
The cladding is formed of a cured product of the actinic radiation curable polymer (b);
In the cured product of the actinic radiation curable polymer (b) forming the cladding part, a low molecular weight compound (a2) having a refractive index lower than that of the cured product or a polymer of the low molecular weight compound (a2) and a maleimide group It is an optical waveguide in which a photoreactive residue exists.

  In the optical waveguide (2) of the present invention, “the refractive index is lower than that of the cured product” means that the active radiation curable polymer (b) is cured without containing the low molecular weight compound (a). This means that the refractive index is lower than the cured product obtained in some cases.

  In the optical waveguide (2) of the present invention, the clad portion is formed of a cured product of the actinic radiation curable polymer (b), and the actinic radiation curable polymer (b) forming the clad portion. In the cured product, there is a photoreactive residue between the low molecular weight compound (a2) or a polymer of the low molecular weight compound (a2) and a maleimide group. And in the optical waveguide (2) of this invention, this core part is suitably selected so that a refractive index may become higher than this clad part.

  Examples of the method for producing the optical waveguide (2) of the present invention include a method example (1) for producing the optical waveguide of the present invention and a method example (2) for producing the optical waveguide of the present invention.

  For example, in the method example (1) for producing the optical waveguide of the present invention, the lower clad (the lower clad 1 in the embodiment shown in FIGS. 1 to 6) contains the low molecular weight compound (a2). The actinic radiation curable polymer (b) to be produced is photocured, and the core encapsulating upper layer clad forming polymer (in the embodiment shown in FIGS. 1 to 6, the core encapsulating upper layer clad forming polymer). The active radiation curable polymer (b) containing the low molecular weight compound (a2) is used as the polymer for forming the layer 8, and the polymer for forming the core (in FIGS. 1 to 6) In the illustrated embodiment, the active radiation curable polymer (b) is a polymer for forming the layer 2), and the refractive index after curing is higher than that of the lower cladding and the core inner sealing upper cladding. For The Rukoto, it is possible to manufacture an optical waveguide (2) of the present invention.

  Table 3 shows an example of the embodiment manufactured by the method example (1) for manufacturing the optical waveguide of the present invention out of the optical waveguide (2) of the present invention.

  In Table 3, (E1) is formed by a cured product of the actinic radiation curable polymer (b), and the low molecular weight compound (a2) or the low molecular weight compound (a2) is contained in the cured product. This is a material in which a photoreactive residue of a polymer of the above and a maleimide group exists. (F1) is formed of a material other than the cured product of the actinic radiation curable polymer (b), and has a higher refractive index than the lower cladding and the core-encapsulating upper cladding. (G1) is formed of a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) It is a material in which a photoreactive residue with a maleimide group exists. (H1) is formed of a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) Neither the photoreactive residue with the maleimide group nor the photoreactive residue between the low molecular weight compound (a2) or the polymer of the low molecular weight compound (a2) and the maleimide group is present.

  In the optical waveguide (2) of the present invention, the embodiment manufactured by the method example (1) for manufacturing the optical waveguide of the present invention is not limited to the one shown in Table 3, for example, The core part is formed of a cured product of the actinic radiation curable polymer (b), and the low molecular weight compound (a2) or a polymer of the low molecular weight compound (a2) and a maleimide in the cured product Although a photoreactive residue with a group exists, since the abundance is smaller than that of (E1), a material having a refractive index higher than that of the lower cladding and the core-encapsulating upper cladding is also included. .

  Further, for example, in the method example (2) for manufacturing the optical waveguide of the present invention, the lower clad (the lower clad 21 in the embodiment shown in FIGS. 8 to 13) and the upper clad (FIGS. 8 to In the embodiment shown in 13, the upper clad 30) is prepared by photocuring the active radiation curable polymer (b) containing the low molecular weight compound (a2), and the active radiation curable As a polymer for forming a polymer (b) layer (in the embodiment shown in FIGS. 8 to 13), the low molecular weight compound (a2) is used as the polymer for forming the active radiation curable polymer (b) layer 22. By using the actinic radiation curable polymer (b) containing, the optical waveguide (2) of the present invention can be produced.

  In addition, Table 4 shows an example of the embodiment manufactured by the method example (2) of manufacturing the optical waveguide of the present invention out of the optical waveguide (2) of the present invention.

  In Table 4, (E2) is formed by a cured product of the actinic radiation curable polymer (b), and the low molecular weight compound (a2) or the low molecular weight compound (a2) is contained in the cured product. This is a material in which a photoreactive residue of a polymer of the above and a maleimide group exists. (H2) is formed by a cured product of the actinic radiation curable polymer (b), and in the cured product, the low molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) and maleimide None of the photoreactive residue with the group and the photoreactive residue between the low molecular weight compound (a2) or the polymer of the low molecular weight compound (a2) and the maleimide group are present.

  In the optical waveguide (2) of the present invention, the embodiment manufactured by the method example (2) for manufacturing the optical waveguide of the present invention is not limited to the one shown in Table 4, for example, Since a small amount of the low molecular weight compound (a2) remains during the low molecular weight compound volatilization step, the core portion is formed of a cured product of the active radiation curable polymer (b), and In the cured product, there is a photoreactive residue between the low molecular weight compound (a2) or a polymer of the low molecular weight compound (a2) and a maleimide group, but the abundance is smaller than that of (E2). In addition, the lower clad, the intermediate clad portion, and the material having a higher refractive index than the upper clad are also included.

  In the optical waveguide (2) of the present invention, the core part and the clad part are formed of a cured product of the actinic radiation curable polymer (b). Show almost the same value, it is difficult for stress to be generated between the core part and the clad part, so that cracking due to curing shrinkage is less likely to occur, adhesion force or It is preferable in that it has an advantage of excellent adhesive force, and is a cured product of the actinic radiation curable polymer (b) that forms the core part, and curing of the actinic radiation curable polymer (b) that forms the cladding part. It is particularly preferable that the product is a cured product of the same actinic radiation curable polymer (b).

  The active radiation curable polymer (b) according to the optical waveguide of the present invention has a maleimide group in the polymer molecule. Then, by irradiating the actinic radiation curable polymer (b) with actinic radiation, the maleimide group in one polymer undergoes a crosslinking reaction with the maleimide group in the other polymer to dimerize. As a result, the actinic radiation curable polymer (b) is crosslinked with a maleimide group dimer, photocured, and becomes a cured product.

  The actinic radiation curable polymer (b) is a polymer having a cyclohexane skeleton or a cyclopentane skeleton as a whole or a part of the main chain and a maleimide group as a side chain, and has excellent transparency in the vicinity of 850 nm. In addition, since it exhibits physical properties with flexibility, it is preferable as a multimode polymer optical waveguide material.

The actinic radiation curable polymer (b) is selected from one or more structural units selected from the structural units represented by the following general formula (1) and from the structural units represented by the following general formula (3). A polymer in which one or more structural units are randomly copolymerized and the molar ratio of the structural units represented by the following general formula (1) is 10 to 100% (hereinafter, such a polymer) Is also referred to as actinic radiation curable polymer (b-1).) Is preferable in that crosslinking during the photocuring reaction is sufficiently performed and the toughness of the waveguide film can be increased.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[In the formula, A represents a methylene group; a linear or branched hydrocarbylene group having 2 to 6 carbon atoms; a linear or branched halohydrocarbylene group having 2 to 6 carbon atoms; Or a branched perhalocarbylene group having 2 to 6 carbon atoms; a substituted or unsubstituted cyclic or polycyclic hydrocarbylene group having 5 to 12 carbon atoms; a substituted or unsubstituted cyclic group having 5 to 12 carbon atoms Or a polycyclic halohydrocarbylene group; or a substituted or unsubstituted C5-C12 cyclic or polycyclic perhalocarbyl group. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom; a linear or branched hydrocarbyl group having 1 to 25 carbon atoms; a linear or branched halohydrocarbyl group having 1 to 25 carbon atoms. Or a linear or branched perhalocarbyl group having 1 to 25 carbon atoms, which may be the same or different. )
General formula (3):

(Wherein, Y _{is, -CH 2 -, - CH 2} -CH 2 - or -O- .n is at least ^{.R 7, R 8,} R ⁹ and ^{R 10} is an integer from 0 to 5 One is a linear, branched or cyclic C1-C25 hydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms; A linear, branched or cyclic halohydrocarbyl group having 1 to 25 carbon atoms having a heteroatom selected from oxygen atom, nitrogen atom, sulfur atom and silicon atom; one or more oxygen atoms, nitrogen atom, A linear, branched or cyclic perhalocarbyl group having 1 to 25 carbon atoms having a heteroatom selected from a sulfur atom and a silicon atom; selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms Heteroatom An aryl group having 1 to 25 carbon atoms; an aralkyl pendant group having 1 to 25 carbon atoms having a hetero atom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms, and silicon atoms; linear, branched Or a linear, branched or cyclic halohydrocarbyl group having 1 to 25 carbon atoms; a linear, branched or cyclic perhalocarbyl group having 1 to 25 carbon atoms; carbon An aryl group having 1 to 25 carbon atoms; or an aralkyl pendant group having 1 to 25 carbon atoms, and the remainder of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ is a hydrogen atom.)

  As a maleimide group represented by the general formula (2), the following formula (2-1):

The structure represented by is mentioned.

  In the present invention, the “hydrocarbyl group” is a group containing a carbon skeleton in which each carbon atom is appropriately substituted with at least one hydrogen atom. That is, the “hydrocarbyl group” is a hydrocarbon group or a group in which a part of the hydrogen atoms of the hydrocarbon group is substituted with a substituent having a nitrogen atom or a substituent having an oxygen atom.

  Specific examples of the hydrocarbyl group include a linear or branched alkyl group having 1 to 25 carbon atoms; a linear or branched alkenyl group having 2 to 24 carbon atoms; a linear or branched group. An alkynyl group having 2 to 24 carbon atoms; a cycloalkyl group having 5 to 25 carbon atoms having a linear or branched group; an aryl group having 6 to 24 carbon atoms; an aralkyl group having 7 to 24 carbon atoms; More specifically, benzyl group, phenylpropyl group, naphthylmethyl group, naltylethyl group and the like can be mentioned.

  In the present invention, the “halohydrocarbyl group” means that at least one hydrogen atom (but not all hydrogen atoms) of the hydrocarbyl group is a halogen atom such as a chlorine atom, a bromine atom, an iodine atom, or a fluorine atom. A group substituted with an atom. As the halohydrocarbyl group, specifically, for example, at least one hydrogen atom (but not all hydrogen atoms) of a linear or branched alkyl group having 1 to 25 carbon atoms is a halogen atom. A substituted group; a group in which at least one hydrogen atom (but not all hydrogen atoms) of a linear or branched alkenyl group having 2 to 24 carbon atoms is substituted with a halogen atom; A group in which at least one hydrogen atom (but not all of the hydrogen atoms) of the branched alkynyl group having 2 to 24 carbon atoms is substituted with a halogen atom; a carbon number of 5 having a linear or branched group A group in which at least one hydrogen atom (but not all hydrogen atoms) of a cycloalkyl group of ˜25 is substituted with a halogen atom; at least one hydrogen atom of an aryl group having 6 to 24 carbon atoms A group in which (but not all hydrogen atoms) is substituted with a halogen atom; at least one hydrogen atom (but not all hydrogen atoms) in an aralkyl group having 7 to 24 carbon atoms is substituted with a halogen atom Group.

  In the present invention, the “perhalocarbyl group” is a group in which all hydrogen atoms of the hydrocarbyl group are substituted with halogen atoms such as a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Specific examples of the perhalocarbyl group include, for example, a group in which all hydrogen atoms of a linear or branched alkyl group having 1 to 25 carbon atoms are substituted with halogen atoms; linear or branched carbon A group in which all hydrogen atoms of the alkenyl group having 2 to 24 are substituted with halogen atoms; a group in which all hydrogen atoms of the linear or branched alkynyl group having 2 to 24 carbon atoms are substituted with halogen atoms; A group in which all the hydrogen atoms of a cycloalkyl group having 5 to 25 carbon atoms having a linear or branched group are substituted with a halogen atom; and all the hydrogen atoms in an aryl group having 6 to 24 carbon atoms are halogen atoms. A substituted group; a group in which all the hydrogen atoms of an aralkyl group having 7 to 24 carbon atoms are substituted with halogen atoms.

  Examples of the alkyl group related to the hydrocarbyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, Examples include, but are not limited to, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group. In addition, examples of the alkenyl group related to the hydrocarbyl group include, but are not limited to, a vinyl group, an allyl group, and a propenyl group. Examples of the alkynyl group related to the hydrocarbyl group include, but are not limited to, an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, and a 2-butynyl group. Examples of the cycloalkyl group related to the hydrocarbyl group include, but are not limited to, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the aryl group related to the hydrocarbyl group include, but are not limited to, a phenyl group, a biphenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group related to the hydrocarbyl group include, but are not limited to, a benzyl group and a phenethyl group. The halohydrocarbyl group is a group in which at least one hydrogen atom (but not all hydrogen atoms) of these groups is substituted with a halogen atom, and the perhalocarbyl group is a group of these groups. A group in which all hydrogen atoms are substituted with halogen atoms.

  Moreover, the hydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms is a hydrocarbyl group having a carbon atom substituted by one or more heteroatoms. . Examples thereof include hydrocarbyl groups having groups such as ether groups, glycidyl ether groups, alcohol groups, carboxylic acid groups, ester groups, acrylic groups, trialkoxysilyl groups, silyl groups, and siloxy groups. In addition, the halohydrocarbyl group and the perhalocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms, except for the presence or number of substitution with halogen atoms, It is the same as the hydrocarbyl group having a hetero atom selected from the one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms.

  In the present invention, the “hydrocarbylene group” is the same as the hydrocarbyl group except that the hydrocarbyl group is a monovalent group, whereas the hydrocarbylene group is a divalent group. Similarly, in the present invention, the “halohydrocarbylene group” means a halohydrocarbyl group, except that the halohydrocarbyl group is a monovalent group, whereas the halohydrocarbylene group is a divalent group. It is the same. Similarly, in the present invention, the “perhalocarbylene group” is the same as the perhalocarbyl group except that the perhalocarbyl group is a monovalent group, whereas the perhalocarbylene group is a divalent group. It is.

  In the present invention, the “aralkyl pendant group” refers to a lower alkyl group substituted with an aryl group, such as a benzyl group, a phenylpropyl group, a naphthylmethyl group, or a naltylmethyl group.

  The molar ratio (%) of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-1) is “{the structural unit corresponding to the structural unit represented by the general formula (1). Of the total of the structural units corresponding to the structural unit represented by the general formula (1) + the total number of the structural units corresponding to the structural unit represented by the general formula (3)} × 100 ", 10 to 100%, preferably 20 to 60%, particularly preferably 20 to 50%. When the molar ratio of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-1) is within the above range, crosslinking during the photocuring reaction is sufficiently performed. In addition, the toughness of the waveguide film can be increased.

The actinic radiation curable polymer (b) includes at least one structural unit selected from the structural units represented by the general formula (1) and a structural unit represented by the following formula (4): A polymer copolymerized at random, wherein the molar ratio of the structural unit represented by the general formula (1) is 10 to 100% (hereinafter, such a polymer is referred to as an actinic radiation curable polymer (b-2). ))).
Formula (4):

  The molar ratio (%) of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-2) is “{the structural unit corresponding to the structural unit represented by the general formula (1). Of the total of the structural units corresponding to the structural unit represented by the general formula (1) + the total number of the structural units corresponding to the structural unit represented by the general formula (4)} × 100 ", 10 to 100%, preferably 20 to 60%, particularly preferably 20 to 50%. When the molar ratio of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-2) is within the above range, crosslinking during the photocuring reaction is sufficiently performed. In addition, the toughness of the waveguide film can be increased.

The actinic radiation curable polymer (b) is a polymer obtained by polymerizing a structural unit represented by the following general formula (5) (hereinafter, such a polymer is also referred to as an actinic radiation curable polymer (b-3)). ). ^R 1 in the structural unit represented by the following general formula ^{(5), R 2, R} 3 and ^{R 4, R 1, R 2, R} 3 and ^{R 4} in the structural unit represented by the general formula (1) It is the same.
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is a maleimide group represented by the general formula (2). The rest of R ¹ , R ² , R ³ and R ⁴ is A hydrogen atom; a linear or branched hydrocarbyl group having 1 to 25 carbon atoms; a linear or branched halohydrocarbyl group having 1 to 25 carbon atoms; or a linear or branched group having 1 to 25 carbon atoms Perhalocarbyl group, which may be the same or different.)

  The actinic radiation curable polymer (b) has one or more structural units selected from the structural units represented by the general formula (1) or the structural units represented by the general formula (5). It is an olefin polymerization polymer, and the polymerization ratio of the structural unit represented by the general formula (1) or the structural unit represented by the general formula (5) is 10 to 100 in terms of a polymerization monomer in terms of a molar ratio to the total olefin polymerization monomer. %, Preferably 20-60%, particularly preferably 20-50%. The olefin polymerized polymer is a polymer obtained by using olefins as polymerization monomers and polymerizing the olefins.

  The molecular weight of the actinic radiation curable polymer (b) is not particularly limited, but is preferably 60000 to 150,000 in weight average molecular weight (Mw), particularly preferably 80000 to 120,000.

  The refractive index of the cured product of the actinic radiation curable polymer (b) is preferably 1.54 to 1.60, particularly preferably 1.55 to 1.59. When the refractive index of the cured product of the actinic radiation curable polymer (b) is within the above range, the refractive index can be easily adjusted.

The low molecular weight compound (a) according to the optical waveguide of the present invention is a compound (reactive monomer) that reacts with a maleimide group when irradiated with actinic radiation, such as vinyl ethers, thiols, and (meth) acrylates. Kind. The vinyl ethers as the low molecular weight compound (a) are compounds having a vinyl ether group (CH ₂ ═CH—O—). The thiols as the low molecular weight compound (a) are compounds having a thiol group (—SH). The (meth) acrylates as the low molecular weight compound (a) have an acrylate group (CH ₂ ═CH—CO—O—) or a methacrylate group (CH ₃ —CH═CH—CO—O—). A compound.

  The low molecular weight compound (a) has a substituent or an element that contributes to changing the refractive index of the cured product of the active radiation curable polymer (b) together with a reactive group that photoreacts with the maleimide group. Examples of substituents or elements that contribute to increasing the refractive index of the cured product of the active radiation curable polymer (b) include substituents such as phenyl groups and aralkyl pendant groups, sulfur, iron, lead, gold , Platinum, silver, copper, chromium, cadmium, mercury, zinc, arsenic, manganese, cobalt, nickel, molybdenum, tungsten, tin, bismuth and the like. Examples of the substituent or element that contributes to lowering the refractive index of the cured product of the actinic radiation curable polymer (b) include a substituent such as a silanol group and an element such as fluorine. In addition, the thiol group (-SH group) in the thiols is a reactive group that photoreacts with the maleimide group, and the sulfur element derived from the thiol group after the thiol group has reacted is the active radiation curable polymer. It functions as an element that increases the refractive index of the cured product (b).

  In the optical waveguide of the present invention, the low molecular weight compound (a) has a structure after photoreacting with the maleimide group of the actinic radiation curable polymer (b), and the actinic radiation curable polymer (b) is cured. It exists in things. In the case of the low molecular weight compound (a) in which the low molecular weight compound (a) undergoes a polymerization reaction between the low molecular weight compounds (a) by irradiation with actinic radiation, the polymerization of the low molecular weight compound (a) is performed. The product exists in the cured product of the active radiation curable polymer (b) in a structure after photoreacting with the maleimide group of the active radiation curable polymer (b).

  Since the low molecular weight compound (a) has a lower refractive index and a higher refractive index than the cured product of the active radiation curable polymer (b), the active radiation is included in the low molecular weight compound (a). Those having a higher refractive index than the cured product of the curable polymer (b) are used as the low molecular weight compound (a1), while the active radiation curable polymer (b) of the low molecular weight compound (a). Those having a refractive index lower than that of the cured product are used as the low molecular weight compound (a2). For example, the vinyl ethers as the low molecular weight compound (a) have a higher refractive index and a lower refractive index than the cured product of the actinic radiation curable polymer (b). Those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a1), while among the vinyl ethers, the actinic radiation curable polymer (b) is cured. Those having a refractive index lower than that of the product are used as the low molecular weight compound (a2). Further, the thiols as the low molecular weight compound (a) include those having a higher refractive index than those of the cured product of the active radiation curable polymer (b) and those having a lower refractive index. Those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a1), while among the thiols, the actinic radiation curable polymer (b) Those having a refractive index lower than that of the cured product are used as the low molecular weight compound (a2). In addition, the (meth) acrylates as the low molecular weight compound (a) include those having a higher refractive index and those having a lower refractive index than the cured product of the actinic radiation curable polymer (b). ) Among the acrylates, those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a1), while among the (meth) acrylates, Those having a refractive index lower than that of the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a2).

  The molecular weight of the low molecular weight compound (a) is 40 to 800, preferably 60 to 500, particularly preferably 100 to 200.

Here, the photoreactive residue between the low molecular weight compound (a) or a polymer of the low molecular weight compound (a) and a maleimide group will be described. For example, when the low molecular weight compound (a) is the thiols (R′-SH), the active radiation curable polymer (b) containing R′-SH as shown in the following reaction formula (A) When the layer is irradiated with actinic radiation, the maleimide group (X) in the actinic radiation curable polymer (b) (the portion surrounded by the dotted line in the following reaction formula (A)) and R′-SH react with each other. , A photoreactive residue (Y1) of R′-SH and a maleimide group (a portion surrounded by a dotted line in the following reaction formula (A)) is generated. As described above, in the present invention, the photoreactive residue between the low molecular weight compound (a) and the maleimide group is generated by photoreaction of the maleimide group and the low molecular weight compound (a). In other words, it is a group obtained by photoreacting the low molecular weight compound (a) to a maleimide group. That is, the photoreactive residue between the low molecular weight compound (a) and the maleimide group is a photoreaction residue of the low molecular weight compound (a) that binds to the structure after the photoreaction of the maleimide group and the structure after the photoreaction of the maleimide group. It is a group consisting of a structure after the reaction, and the structure after the photoreaction of the low molecular weight compound (a) is a group bonded to the group after the reaction of the maleimide group.
Reaction formula (A):

(In the reaction formula (A), * indicates that it is bonded to the actinic radiation curable polymer (b).)

  In the above reaction formula (A), it has been explained that the photoreactive residue between the low molecular weight compound (a) and the maleimide group is generated by an ene-thiol reaction between the maleimide group and the thiols. In the invention, the reaction form is not limited to this, and examples of the photoreactive residue of the low molecular weight compound (a) and the maleimide group include the low molecular weight compound (a), the vinyl ethers, the acrylates, and the In the case of methacrylates, these vinyl ethers, the acrylates, or the methacrylates and maleimide groups formed by photoreacting these compounds with double bonds of maleimide groups in the active radiation curable polymer (b). Examples include photoreactive residues with double bonds. Examples of the photoreactive residue of the low molecular weight compound (a) and the maleimide group include photopolymers of the vinyl ethers, acrylates or methacrylates in the active radiation curable polymer (b). And photoreactive residues generated by photoreaction with the double bond of the maleimide group. Therefore, regardless of the reaction form, the low molecular weight compound (a) or a polymer of the low molecular weight compound (a) and a maleimide group are photoreacted to produce the low molecular weight compound (a) and the maleimide group. It is included in the photoreactive residue.

  The amount of the photoreactive residue between the low molecular weight compound (a) or the polymer of the low molecular weight compound (a) and the maleimide group in the cured product of the active radiation curable polymer (b) is low before the reaction. The actinic radiation curable polymer (b) before the reaction is appropriately selected depending on how much the refractive index of the molecular weight compound (a) and the refractive index of the cured product of the actinic radiation curable polymer (b) are changed. The amount of the low molecular weight compound (a) is preferably 2 to 50% by mass, and the amount of 5 to 30% by mass is particularly preferable.

The cured product of the actinic radiation curable polymer (b) contains a photoreaction accelerator such as a photoradical generator as long as the light propagation loss does not increase in order to promote the photocrosslinking reaction between maleimide groups. Can do. Examples of the photo radical generator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like. Is mentioned.
In addition, the cured product of the actinic radiation curable polymer (b) can contain a photosensitizer within a range where the light propagation loss does not increase in order to expand the photosensitive wavelength region of the photocrosslinking reaction. Examples of the photosensitizer include thioxanthone such as 2-chlorothioxanthone, 2-isopropylthioxanthone and 2-chloropropoxythioxanthone, and quinones such as 2,3-dichloro-5,6-dicyanobenzoquinone and anthraquinone.

  Moreover, the cured product of the actinic radiation curable polymer (b) may contain additives such as an adhesion aid, an antioxidant, and a dissolution accelerator, if necessary. Examples of the adhesion assistant include vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, trimethoxysilylnorbornene. And silane coupling agents such as triethoxynorbornene and trimethoxysilylethylnorbornene.

  As a material other than the cured product of the active radiation curable polymer (b) forming the core part and the clad part of the optical waveguide of the present invention, a material that can be used as a material for the core part or the clad part of the optical waveguide. Is not particularly limited, but has high transparency, excellent heat resistance and water absorption resistance, and further has high mechanical strength and excellent adhesion to the cured product of the active radiation curable polymer (b). Is preferred. The material other than the cured product of the active radiation curable polymer (b) that forms the core part and the clad part is used in which part of the optical waveguide. When the refractive index is to be increased, and when used as a cladding portion, the refractive index is appropriately selected in consideration of how much the refractive index is to be lower than the core portion.

  Examples of such materials include a photopolymerizable norbornene resin, a photopolymerizable acrylic acid resin, a photopolymerizable methacrylic acid resin, a photopolymerizable epoxy resin, a photopolymerizable oxetane resin, Photopolymerizable styrenic resins and the like can be mentioned, and among these, a photopolymerizable alicyclic epoxy resin is preferable because it is particularly excellent in transparency. These may be used alone or in combination of two or more.

  The lower clad according to the method example (2) for producing the optical waveguide of the present invention is produced by a conventionally known method. Usually, a varnish in which the actinic radiation curable polymer for forming the lower clad is dissolved is applied onto an arbitrary substrate, for example, a glass substrate, a silicon wafer, etc. The lower cladding is formed on the top.

  In the actinic radiation curable polymer layer preparation step according to the method example (2) for producing the optical waveguide of the present invention, as a method for producing the actinic radiation curable polymer (b) layer on the lower clad, for example, First, the actinic radiation curable polymer (b) and the low molecular weight compound (a) are dissolved or dispersed in a solvent to prepare a varnish for preparing the actinic radiation curable polymer (b) layer. On the lower clad, it is applied with a doctor blade, a circular coater, a spray coater, a die coater, a comma coater or the like, and then the solvent is volatilized from the varnish to produce the active radiation curable polymer (b) layer. A method is mentioned. In this method, the solvent only needs to have a lower boiling point than the low molecular weight compound (a), and examples thereof include toluene, xylene, and mesitylene. Moreover, this photoreaction accelerator, this photosensitizer, and this additive can be added to this varnish as needed.

  The first irradiation step according to the method example (2) for producing the optical waveguide of the present invention is a step of irradiating the active radiation curable polymer (b) layer with a pattern mask and irradiating with active radiation.

  In the first irradiation step, the active radiation to be applied to the active radiation curable polymer (b) layer may be any radiation that can cause a photoreaction, and examples thereof include visible light, ultraviolet light, infrared light, and laser light. , Electron beam, X-ray and the like. Of these, ultraviolet rays and laser beams are preferred.

  The mask is for preventing the active radiation curable polymer (b) layer from being irradiated with active radiation. When the low molecular weight compound (a1) is used as the low molecular weight compound (a), the exposed portion irradiated with the active radiation in the first irradiation step becomes a core portion, and the active radiation is not irradiated. Since the exposed portion becomes the intermediate layer cladding portion, the pattern shape of the mask is made to be the pattern shape of the intermediate layer cladding portion. On the other hand, when the low molecular weight compound (a2) is used as the low molecular weight compound (a), the exposed portion irradiated with actinic radiation in the first irradiation step becomes an intermediate clad portion and is not irradiated with actinic radiation. Since the unexposed portion becomes the core portion, the pattern shape of the mask is made to be the pattern shape of the core portion.

In the first irradiation step, the irradiation amount of the active radiation is appropriately selected. In the first irradiation step, if the irradiation amount is such that the low molecular weight compound (a) reacts with the maleimide group. Good. In the first irradiation step, the low molecular weight compound (a) is reacted with a maleimide group, whereby the low molecular weight compound (a) or a polymer of the low molecular weight compound (a) is converted into the active radiation curable polymer ( Since the purpose is to react with the maleimide group of b), in the second irradiation step, by the crosslinking reaction between maleimide groups, the irradiation dose for curing the actinic radiation curable polymer (b), The irradiation amount may be small. For example, when the actinic radiation is ultraviolet, a light source containing 200 to 450 nm, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a metal halide lamp is used, and the actinic radiation curable polymer (b) layer is 500 to 2000 mJ / cm. Irradiate ² ultraviolet rays. Moreover, the irradiation amount of actinic radiation can be adjusted with the irradiation intensity and irradiation time of actinic radiation. For example, ultraviolet rays having an irradiation intensity of 10 to 40 mW / cm ² are irradiated for 100 to 300 seconds.

  In the first irradiation step, the low molecular weight compound (a) or a polymer of the low molecular weight compound (a) is bonded to a maleimide group, so that the low molecular weight is exposed in the exposed area irradiated with active radiation. The polymer of the compound (a) or the low molecular weight compound (a) reacts with the maleimide group of the actinic radiation curable polymer (b) to form the low molecular weight compound (a) or the low molecular weight compound (a). A photoreactive residue between the polymer and the maleimide group is generated.

  In the low molecular weight compound volatilization step according to the method example (2) for producing the optical waveguide of the present invention, the active radiation in the active radiation curable polymer (b) layer was not irradiated under heating or under reduced pressure. The low molecular weight compound (a) is volatilized from the unexposed area. The term “under heating or under reduced pressure” refers to heating the active radiation curable polymer (b) layer, placing it under a reduced pressure, or reducing the pressure while heating.

  In the low molecular weight compound volatilization step, the heating temperature or the degree of reduced pressure is such that the content of the low molecular weight compound (a) in the actinic radiation curable polymer (b) layer in the unexposed area is not more than a predetermined content. As described above, the heating temperature is preferably 50 to 180 ° C., particularly preferably 80 to 150 ° C., depending on the type of the active radiation curable polymer (b) and the low molecular weight compound (a). The degree of vacuum is usually 0.1 to 0.5 kPa, preferably 0.1 to 0.3 kPa. Further, the heating time or the reduced pressure time is appropriately selected so that the content of the low molecular weight compound (a) in the actinic radiation curable polymer (b) layer in the unexposed part is not more than a predetermined content. The

  In the actinic radiation curable polymer (b) layer in the unexposed area that has not been irradiated with actinic radiation, since the low molecular weight compound (a) is not bonded to a maleimide group, under heating or under reduced pressure, Volatilizes from the active radiation curable polymer (b) layer. Therefore, by performing the low molecular weight compound volatilization step, the active radiation curable polymer (b) layer prepared in the active radiation curable polymer layer preparation step is added to the active radiation curable polymer layer (b) layer. Forming a portion containing the photoreactant of the low molecular weight compound (a) in the same amount as the content and a portion not containing the photoreactant of the low molecular weight compound (a) or having a reduced content Can be made.

  In the second irradiation step according to the method example (2) for producing the optical waveguide of the present invention, the active radiation curable polymer (b) layer is irradiated with active radiation to the active radiation curable polymer ( b) A step of curing the actinic radiation curable polymer (b) by causing a crosslinking reaction in the maleimide groups of the entire layer.

In the second irradiation step, the active radiation applied to the active radiation curable polymer (b) layer is the same as the active radiation applied to the active radiation curable polymer (b) layer in the first irradiation step. It is. In the second irradiation step, the irradiation amount of the actinic radiation is appropriately selected, the maleimide groups of the actinic radiation curable polymer (b) undergo a crosslinking reaction, and the actinic radiation curable polymer (b) is irradiated with light. A dose that cures is selected. For example, when the actinic radiation is ultraviolet, a light source including 200 to 450 nm, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a metal halide lamp is used, and the actinic radiation curable polymer (b) layer is coated with 2000 to 10,000 mJ / cm. Irradiate ² ultraviolet rays. For example, ultraviolet rays having an irradiation intensity of 20 to 40 mW / cm ² are irradiated for 100 to 300 seconds.

  And by performing this 2nd irradiation process, this actinic radiation curable polymer (b) layer becomes a hardened | cured material layer of this actinic radiation curable polymer (b).

  In the upper-layer cladding manufacturing step according to the method example (2) for manufacturing the optical waveguide of the present invention, an upper-layer cladding is manufactured on the cured layer of the active radiation curable polymer (b) to obtain an optical waveguide. .

  The lower cladding according to the method example (1) for manufacturing the optical waveguide of the present invention is the same as the lower cladding according to the method example (2) for manufacturing the optical waveguide of the present invention.

  In the core layer forming polymer layer forming step according to the method example (1) for producing the optical waveguide of the present invention, the core layer forming polymer layer is cured by irradiating the active radiation on the lower clad. The method of forming an active radiation curable polymer layer according to the method example (2) for producing the optical waveguide of the present invention is the same as the method for producing the optical waveguide of the present invention except that the polymer for forming the core part is used for forming the polymer layer. It is.

  Since the core portion curing step according to the method example (1) for producing the optical waveguide of the present invention is a step of photocuring the polymer for forming the core portion of the exposed portion by irradiating actinic radiation, The second irradiation step according to the method example (2) for producing the optical waveguide of the present invention, except that the target to be irradiated with actinic radiation is the polymer layer for forming the core part and the photomask is used. It is the same.

  And by performing this core part hardening process, the exposure part of the polymer layer for this core part formation turns into hardened | cured material.

  The developing step according to the method example (1) for producing the optical waveguide of the present invention is a step of removing the unexposed portion with a developer. Examples of the developer include organic solvents such as toluene, xylene, mesitylene, tetrahydrofuran, cyclohexane, cyclopentanone, methyl ethyl ketone, 2-pentanone, limonene, and decalin. These organic solvents may be used alone or in combination of two or more. In order to control the solubility of the developer, a poor solvent such as water or alcohols such as ethanol and isopropyl alcohol can be added to the organic solvent.

  In the polymer layer forming step for forming the core encapsulating upper layer clad according to the method example (1) for producing the optical waveguide of the present invention, a polymer layer for forming the core encapsulating upper layer cladding is formed on the lower layer cladding and the core portion. The method of forming the active radiation curable polymer layer according to the method example (2) for producing the optical waveguide of the present invention, except that the polymer for forming the polymer layer is formed by using the core-encapsulating upper layer clad forming polymer. It is the same.

  Then, by performing the polymer layer forming step for forming the core-encapsulated upper layer clad according to the method example (1) for producing the optical waveguide of the present invention, the core-encapsulated upper layer is formed on the lower clad and the core unit. A polymer layer for forming a clad is formed.

  Since the core part encapsulating upper layer clad curing step according to the method example (1) for producing the optical waveguide of the present invention is a process of curing the core encapsulating upper layer clad forming polymer by irradiating with active radiation, It is the same as that of this 2nd irradiation process which concerns on the example (2) of methods of manufacturing the optical waveguide of this invention except that the object which irradiates actinic radiation is the polymer layer for this core part encapsulating upper layer clad formation.

  Then, the core-encapsulating upper-layer cladding is formed on the lower-layer cladding and the core by performing the core-encapsulating upper-layer cladding curing step according to the method example (1) for producing the optical waveguide of the present invention. Thus, an optical waveguide is obtained.

  In the optical waveguides (1) and (2) of the present invention, the kind of the active radiation curable polymer (b), the kind of the low molecular weight compound (a), the low molecular weight compound (a) or the low molecular weight compound (a The refractive index difference between the core portion and the clad portion can be adjusted by appropriately selecting the abundance of the photoreactive residue between the polymer and the maleimide group. The difference in refractive index between the core portion and the clad portion is not particularly limited, but is preferably 0.3 to 4.0%, particularly preferably 0.5 to 2.5%. In addition, the abundance of the photoreactive residue between the low molecular weight compound (a) or the polymer of the low molecular weight compound (a) and the maleimide group is the amount of the actinic radiation curable polymer (b) before the photoreaction. It is adjusted by the content of the low molecular weight compound (a).

  In the optical waveguides (1) and (2) of the present invention, the refractive index of the cured product is changed either in the cured product forming the core part or in the cured product forming the cladding part, or both. A photoreactive residue between the low molecular weight compound (a) or a polymer of the low molecular weight compound (a) and a maleimide group exists. Therefore, in the optical waveguides (1) and (2) of the present invention, the kind of the low molecular weight compound (a) and the light of the low molecular weight compound (a) or the polymer of the low molecular weight compound (a) and the maleimide group By selecting the abundance of the reactive residue, the difference in refractive index between the core and cladding of the optical waveguide can be adjusted, so adjustment is made only by the type of polymer for forming the core and cladding. Compared to the case, it is easy to adjust the difference in refractive index between the core portion and the clad portion of the optical waveguide.

  Further, in the conventional optical waveguide in which the difference in refractive index between the core part and the clad part is adjusted only by the kind of polymer for forming the core part and the clad part, the polymer and the clad part for forming the core part are formed. However, in the optical waveguide of the present invention, the polymer for forming the core portion and the polymer for forming the cladding portion are not able to be made into a polymer having the same structure or a similar structure. It can be a polymer having the same structure or a similar structure.

  In the above description, the use of the cured product of the actinic radiation curable polymer (b) has been described for the case of an optical waveguide. However, various polymer materials such as holography, polymer optical fiber, microlens, prism, etc. Applicable.

  That is, the cured product of the actinic radiation curable polymer of the present invention is a cured product of the actinic radiation curable polymer (b), and the cured product of the actinic radiation curable polymer (b) This is a cured product of an actinic radiation curable polymer in which a photoreactive residue between a molecular weight compound (a1) or a polymer of the low molecular weight compound (a1) and a maleimide group exists. The cured product of the actinic radiation curable polymer of the present invention is a cured product of the actinic radiation curable polymer (b), and the cured product of the actinic radiation curable polymer (b) This is a cured product of an actinic radiation curable polymer in which a photoreactive residue between a polymer of the molecular weight compound (a2) or the low molecular weight compound (a2) and a maleimide group exists. These cured products of the actinic radiation curable polymer of the present invention are suitably used for applications such as holography, polymer optical fiber, microlens, and prism.

  Examples of the present invention will be described below in comparison with comparative examples to demonstrate the effects. In addition, these Examples show one embodiment of this invention, and this invention is not limited to these.

Example 1
(1) Synthesis of actinic radiation curable polymer 8.4 g (35.9 mmol) of decylnorbornene (DeNB), phenylethyl in a glove box whose moisture and oxygen concentrations were both controlled to 1 ppm or less and filled with dry nitrogen Weigh 5.3 g (27.0 mmol) of norbornene (PENB) and 6.2 g (27.0 mmol) of dimethylmaleimide norbornene (DMMINB) into a 500 mL vial, add 60 g of dehydrated toluene and 11 g of ethyl acetate, and add a silicon sealer. Covered and sealed the top.
Next, 1.74 g (3.6 mmol) of Ni catalyst represented by the following chemical formula (6) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.
When 1 mL of the Ni catalyst solution represented by the following chemical formula (6) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the above three types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.
In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.
Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. By performing heat drying for 12 hours, actinic radiation curable polymer # 1 having a dimethylmaleimide group (a structural unit represented by the following formula (7-1), a structural unit represented by the following formula (7-2), A polymer in which a structural unit represented by the following formula (7-3) was randomly copolymerized was obtained. The molecular weight distribution of the polymer # 1 is Mw = 100,000, Mn = 40,000 by GPC measurement, and the molar ratio of each structural unit in the polymer # 1 is decylnorbornene structural unit (the following formula (7-1) )) Is 40 mol%, phenylethylnorbornene structural unit (the following formula (7-2)) is 30 mol%, dimethylmaleimide norbornene structural unit (the following formula (7-3)) is 30 mol%, and the refractive index is 1 according to Metricon. .56 (measurement wavelength; 633 nm).
Chemical formula (6):

Formulas (7-1) to (7-3):

  In the above formulas (7-1) to (7-3), the numbers on the lower right of the parentheses of each structural unit represent mol% of each structural unit in the polymer, and each structural unit is continuous. It does not represent what you are doing.

(2) Preparation of actinic radiation curable polymer layer forming varnish V1 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Add 0.1 g of acrylate monomer (Osaka Organic Chemical Co., Ltd. V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) and uniformly dissolve, then filter through 0.2 μm PTFE filter To obtain a clean varnish V1 for forming an active radiation curable polymer layer.
At this time, the ratio of the number of moles of maleimide groups to the number of moles of reactive groups (acrylate groups) of the cyclohexyl acrylate monomer was 0.05.

(3) Production of lower layer clad A photosensitive norbornene resin composition (Avatrel 2000P varnish) was uniformly applied on a silicon wafer with a doctor blade, and then placed in a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, the entire coated surface was irradiated with 100 mJ of ultraviolet light and heated in a dryer at 120 ° C. for 1 hour to cure the coating film to form a lower clad. The formed lower clad had a thickness of 20 μm, was colorless and transparent, and had a refractive index of 1.52 (measurement wavelength: 633 nm).

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the actinic radiation curable polymer layer forming varnish V1 uniformly on the said lower layer clad with a doctor blade, it was thrown into a 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays of 2000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 250 seconds) and heated at 150 ° C. for 1 hour to form an active radiation curable polymer layer. Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.55, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.54.

(5) Formation of upper layer clad A dry film in which Avatrel 2000P was laminated in advance so as to have a dry thickness of 20 μm on a polyethersulfone (PES) film was bonded to the core part and the intermediate layer clad part, and set to 140 ° C. After being put into the vacuum laminator and thermocompression bonded, the entire surface was irradiated with ultraviolet rays at 100 mJ and heated in a dryer at 120 ° C. for 1 hour to cure Avatrel 2000P to form an upper clad to obtain an optical waveguide . At this time, the upper clad was colorless and transparent, and the refractive index was 1.52.

(6) Loss Evaluation of Optical Waveguide Light emitted from an 850 nm VCSEL (surface emitting laser) was introduced into the optical waveguide via a 50 μmφ optical fiber, and received by a 200 μmφ optical fiber to measure the light intensity. In addition, the cutback method was employ | adopted for the measurement. When the waveguide length is plotted on the horizontal axis and the insertion loss is plotted on the vertical axis, the measured values are neatly arranged on a straight line, and the propagation loss can be calculated as 0.03 dB / cm from the inclination.

(Example 2)
(1) Synthesis of actinic radiation curable polymer Using known methods (for example, Japanese Patent Application Laid-Open No. 2003-252963), ring-opening metathesis polymerization of DMMINB monomer is performed, and actinic radiation curable polymer # 2 having a dimethylmaleimide group ( A polymer in which the structural unit represented by the following formula (8) was polymerized was obtained.
Formula (8):

  The molecular weight distribution of Polymer # 2 was Mw = 80,000, Mn = 30,000 by GPC measurement, and the refractive index was 1.57 (measurement wavelength: 633 nm) by Metricon.

(2) Preparation of varnish V2 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 2 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Add 0.1 g of acrylate monomer (Osaka Organic Chemical Co., Ltd. V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) and uniformly dissolve, then filter through 0.2 μm PTFE filter To obtain a clean varnish V2 for forming an active radiation curable polymer layer.
At this time, the ratio of the number of moles of maleimide groups to the number of moles of reactive groups (acrylate groups) of the cyclohexyl acrylate monomer was 0.2.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the active radiation curable polymer layer forming varnish V2 on the said lower layer clad with a doctor blade uniformly, it injected | threw-in to 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays of 2000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 250 seconds) and heated at 150 ° C. for 1 hour to form an active radiation curable polymer layer. Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.56, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.55.

(5) Formation of upper clad It carried out by the method similar to Example 1, and obtained the optical waveguide.

(6) Optical waveguide loss evaluation When the same method as in Example 1 was used, the propagation loss could be calculated as 0.04 dB / cm.

(Example 3)
(1) Synthesis of actinic radiation curable polymer In the same manner as in Example 1, actinic radiation curable polymer # 1 was obtained.

(2) Preparation of varnish V3 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, an antioxidant Irganox 1076 (manufactured by Ciba Geigy) 0.01 g, 2 0.05 g of ethylhexyl- (3-mercaptopropionate) (manufactured by Maruzen Petrochemical Co., Ltd., CAS # 50448-95-8, molecular weight 218.36, boiling point 145 ° C./5.3 kPa) is added and dissolved uniformly. Then, filtration was performed with a 0.2 μm PTFE filter to obtain a clean actinic radiation curable polymer layer forming varnish V3.
At this time, the ratio of the number of moles of the maleimide group to the number of moles of the reactive group (mercapto group (—SH)) of 2-ethylhexyl- (3-mercaptopropionate) was 0.13.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating varnish V3 for actinic radiation curable polymer layer formation uniformly with a doctor blade on the said lower layer clad, it injected | thrown-in to the 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays at 1000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 10 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 6000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 25 mW / cm ² for 240 seconds) and heated at 150 ° C. for 1 hour to form an active radiation curable polymer layer. Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.55, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.54.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Loss evaluation of optical waveguide When performed in the same manner as in Example 1, the propagation loss was calculated to be 0.03 dB / cm.

(Comparative Example 1)
(1) Synthesis of actinic radiation curable polymer 6.7 g (28.7 mmol) of decylnorbornene (DeNB), phenylethyl in a glove box whose water and oxygen concentrations were both controlled to 1 ppm or less and filled with dry nitrogen 13.3 g (66.9 mmol) of norbornene (PENB) was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.
Next, 1.85 g (3.8 mmol) of the Ni catalyst represented by the chemical formula (6) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.
When 1 mL of the Ni catalyst solution represented by the chemical formula (6) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the two types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, and 60 g of THF was added and stirred to obtain a reaction solution.
In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.
Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. By conducting heat drying for 12 hours, actinic radiation curable polymer # 3 (a structural unit represented by the following formula (9-1) and a structural unit represented by the following formula (9-2) are randomly copolymerized. Polymer). The molecular weight distribution of polymer # 3 is Mw = 120,000, Mn = 50,000 by GPC measurement, and the molar ratio of each structural unit in polymer # 3 is decylnorbornene structural unit (following formula (9-1) ) Was 30 mol%, phenylethyl norbornene structural unit (the following formula (9-2)) was 70 mol%, and the refractive index was 1.55 (measurement wavelength: 633 nm) by metricon.
Formulas (9-1) to (9-2):

  In the above formulas (9-1) to (9-2), the numbers on the lower right of the parentheses of each structural unit represent mol% of each structural unit in the polymer, and each structural unit is continuous. It does not represent what you are doing.

(2) Preparation of varnish V4 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 3 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Acrylate monomer (Osaka Organic Chemical Industry V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) 1 g, radical generator Icargacure 651 (Nagase Sangyo, CAS # 24650-42-8) 0.01 g was added and uniformly dissolved, followed by filtration with a 0.2 μm PTFE filter to obtain a clean varnish V4 for forming an active radiation curable polymer layer.

(3) Production of lower clad It was carried out in the same manner as in Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the active radiation curable polymer layer forming varnish V4 on the said lower layer clad with a doctor blade uniformly, it injected | threw-in to 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressed and irradiated with ultraviolet rays at 2000 mJ / cm ² . The mask was removed, and heating was performed in three stages: 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 200 ° C. for 1 hour. After heating, the waveguide pattern was only slightly observed.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² and heated at 150 ° C. for 1 hour to obtain a core portion and an intermediate layer clad having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.550, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.547.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Loss evaluation of optical waveguide When performed in the same manner as in Example 1, the propagation loss was 5 dB / cm.

(Comparative Example 2)
(1) Synthesis of actinic radiation curable polymer In the same manner as in Example 1, actinic radiation curable polymer # 1 was obtained.

(2) Preparation of varnish V5 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexane After adding 1 g of (CAS # 110-82-7) and dissolving it uniformly, it was filtered through a 0.2 μm PTFE filter to obtain clean actinic radiation curable polymer layer forming varnish V5.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of Intermediate Cured Product Layer After the actinic radiation curable polymer layer forming varnish V5 was uniformly applied on the lower clad by a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and irradiated with ultraviolet rays at 2000 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 120 ° C. for 1 hour. After heating, no waveguide pattern was observed.
Next, the entire surface of the actinic radiation curable polymer layer is irradiated with ultraviolet rays at 5000 mJ / cm ² and heated at 150 ° C. for 1 hour to cure the actinic radiation curable polymer layer to form a cured product layer having a thickness of 50 μm. It was.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Evaluation of optical waveguide loss Measurement was not performed because the waveguide structure could not be confirmed.

It is typical sectional drawing (1) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (2) which shows the example of a method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (3) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (4) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (5) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (6) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (7) which shows the form example of the method example (1) which manufactures the optical waveguide of this invention. It is typical sectional drawing (1) which shows the form example of the method example (2) which manufactures the optical waveguide of this invention. It is typical sectional drawing (2) which shows the example of a method example (2) which manufactures the optical waveguide of this invention. It is typical sectional drawing (3) which shows the example of a method example (2) which manufactures the optical waveguide of this invention. It is typical sectional drawing (4) which shows the example of a method example (2) which manufactures the optical waveguide of this invention. It is typical sectional drawing (5) which shows the example of a method example (2) which manufactures the optical waveguide of this invention. It is typical sectional drawing (6) which shows the form example of the method example (2) which manufactures the optical waveguide of this invention.

Explanation of symbols

1, 21 Lower clad 2, 22 Active radiation curable polymer (b) Layer 3, 23 Photomask 4, 24 UV 5, 26 Exposed part 6, 25 Unexposed part 7, 29 Core part 8 Polymer layer 9 Core-encapsulated upper-layer cladding 10, 40 Optical waveguide 11 Intermediate-layer cladding 12 Upper-layer cladding 27 Low-molecular weight compound removal unexposed portion 28 Intermediate-layer cladding 29 Core-portion 30 Upper-layer cladding 31 Active radiation curable polymer (b) Hardened material layer

  According to the present invention, it is easy to adjust the refractive indexes of the core part and the clad part.

Claims (16)

An optical waveguide having a core part for propagating light and a clad part in contact with the core part and having a lower refractive index than the core part,
The core part is formed of a cured product of an actinic radiation curable polymer having a maleimide group,
In the cured product of the active radiation curable polymer having a maleimide group forming the core part, a low molecular weight compound having a higher refractive index than the cured product, or a photoreactive residue of a polymer of the low molecular weight compound and a maleimide group An optical waveguide characterized by the presence of An optical waveguide having a core part for propagating light and a clad part in contact with the core part and having a lower refractive index than the core part,
The cladding is formed of a cured product of an actinic radiation curable polymer having a maleimide group,
In the cured product of the actinic radiation curable polymer having a maleimide group forming the cladding part, a low molecular weight compound having a refractive index lower than that of the cured product, or a photoreactive residue of the polymer of the low molecular weight compound and the maleimide group An optical waveguide characterized by the presence of   2. The optical waveguide according to claim 1, wherein all or part of the clad portion is formed of a cured product of an actinic radiation curable polymer having a maleimide group.   In the cured product of the active radiation curable polymer having a maleimide group that forms all or part of the cladding part, a low molecular weight compound having a lower refractive index than the cured product or a polymer of the low molecular weight compound and a maleimide group 4. The optical waveguide according to claim 3, wherein the photoreactive residue is present.   The cured product of the active radiation curable polymer having a maleimide group forming the core portion and the cured product of the active radiation curable polymer having a maleimide group forming all or part of the cladding portion are the same maleimide group. 5. The optical waveguide according to claim 3, wherein the optical waveguide is a cured product of an actinic radiation curable polymer having the following properties.   3. The optical waveguide according to claim 2, wherein the core portion is formed of a cured product of an actinic radiation curable polymer having a maleimide group.   In the cured product of the active radiation curable polymer having a maleimide group forming the core part, a low molecular weight compound having a higher refractive index than the cured product, or a photoreactive residue of the polymer of the low molecular weight compound and the maleimide group The optical waveguide according to claim 6, wherein the optical waveguide is present.   The active radiation curable polymer cured product of the active radiation curable polymer having maleimide groups forming the core portion and the cured product of the active radiation curable polymer having maleimide groups forming the clad portion have the same maleimide group. The optical waveguide according to claim 6, wherein the optical waveguide is a cured product of a conductive polymer.   The active radiation curable polymer having a maleimide group is a polymer having a cyclohexane skeleton or a cyclopentane skeleton as a whole or a part of a main chain and a maleimide group as a side chain. The optical waveguide according to any one of claims. Olefin polymerization in which the active radiation curable polymer having a maleimide group has one or more structural units selected from structural units represented by the following general formula (1), or structural units represented by the following general formula (5) The polymerization ratio of the structural unit represented by the following general formula (1) or the structural unit represented by the following general formula (5), which is a polymer, is 10 to 100% in terms of a polymerization monomer in terms of a molar ratio to the total olefin polymerization monomer. The optical waveguide according to claim 1, wherein the optical waveguide is provided.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[In the formula, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5; -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is represented by the following general formula (2):

[In the formula, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5; -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. ) The active radiation curable polymer having a maleimide group is selected from one or more structural units selected from structural units represented by the following general formula (1) and a structural unit represented by the following general formula (3): 1 or more types of structural units are the polymers copolymerized at random, The molar ratio of the structural unit represented by following General formula (1) is 10 to 100%, It is characterized by the above-mentioned. The optical waveguide according to any one of claims.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[In the formula, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5; -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )
General formula (3):

(Wherein, Y _{is, -CH 2 -, - CH 2} -CH 2 - or -O- .n is at least ^{.R 7, R 8,} R ⁹ and ^{R 10} is an integer from 0 to 5 One is a linear, branched or cyclic C1-C25 hydrocarbyl group, halohydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms, perhalocarbyl group, an aryl group or an aralkyl pendent group or a linear, branched or cyclic hydrocarbyl group having 1 to 25 carbon atoms, halohydrocarbyl group, perhalocarbyl group, .R 7 is an aryl group or an aralkyl pendent ^radical, R ⁸ , the rest of R ⁹ and R ¹⁰ are hydrogen atoms.) The active radiation curable polymer having a maleimide group is randomly selected from at least one structural unit selected from structural units represented by the following general formula (1) and structural units represented by the following formula (4): The optical waveguide according to any one of claims 1 to 8, wherein the optical waveguide is a copolymerized polymer, and a molar ratio of a structural unit represented by the following general formula (1) is 10 to 100%.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[In the formula, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5; -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )
Formula (4):
9. The optical waveguide according to claim 1, wherein the actinic radiation curable polymer having a maleimide group is a polymer in which a structural unit represented by the following general formula (5) is polymerized.
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is represented by the following general formula (2):

[In the formula, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5; -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )   The optical waveguide according to claim 1, wherein the low molecular weight compound is vinyl ethers, thiols, or (meth) acrylates.   A cured product of an actinic radiation curable polymer having a maleimide group, and a cured product of the actinic radiation curable polymer having a maleimide group has a low molecular weight compound having a higher refractive index than the cured product or polymerization of the low molecular weight compound A cured product of an actinic radiation curable polymer, wherein a photoreactive residue between the product and a maleimide group exists.   A cured product of an actinic radiation curable polymer having a maleimide group, and the cured product of the actinic radiation curable polymer having a maleimide group has a low molecular weight compound having a lower refractive index than the cured product or polymerization of the low molecular weight compound A cured product of an actinic radiation curable polymer, wherein a photoreactive residue between the product and a maleimide group is present.