JP5014658B2 - Light-shielding adhesive composition - Google Patents

Description

  The present invention relates to an adhesive composition, and more particularly to a functional adhesive that shields microwaves such as light.

  In recent years, precision instruments have become smaller and functionality has become important. In particular, due to advances in science and technology, it has become necessary to consider the high positions of the earth such as mountains and the case where precision equipment is used near the universe rather than on the ground, such as by aircraft or rockets.

  Under such circumstances, unlike precision equipment on the ground, precision instruments are exposed to microwaves of various wavelengths such as light and gamma rays. Under such conditions, it is known that organic substances degrade significantly, for example, by decomposition.

  If the member deteriorates, it is easily estimated that the function of the precision instrument is lowered. For this reason, in the present invention, a functional adhesive suitable for creating a precision machine that shields microwaves such as light is provided, the interior is protected from such an environment, and the quality is protected over a long period of time. There is a need.

  Conventionally, as a material for shielding light, it is known that a light shielding layer made of a thermoplastic binder resin and black fine powder is provided on a base film (see, for example, Patent Document 1). When this means is adopted, there is a problem that when the temperature becomes high again, the binder resin is melted and a pinhole is formed in a part thereof, and the deterioration of the light shielding property proceeds from this pinhole part.

  In the semiconductor field, a semiconductor element protective agent in which a thermoplastic resin or the like is added to carbon black is known (for example, see Patent Document 2). When such a material is used, there is a problem that pinholes are formed in the protective agent due to the properties of the thermoplastic resin, and the deterioration of the light-shielding characteristics proceeds from there.

The light-shielding resins of Patent Document 1 and Patent Document 2 have a problem that their color is black, so that they are poor in costume, and cannot withstand the current use.
The costume characteristic that is a problem here is a problem of appearance in appearance, and it is judged that the costume characteristic is the highest when it is not colored and reflects all wavelengths well. In this case, when the light source is white, the appearance color is also white. Also, it looks green when exposed to green light. If black is poorly dressed, it will appear black regardless of the light of any color. The costume property can be considered in the same way outside the visible light region. For example, the light applied by irradiating ultraviolet rays is reflected even though it is slightly attenuated, so that the shielding property is enhanced.

On the other hand, as a light-shielding resin having reflectivity, there is known a method of obtaining a white reflective screen as a result by providing a portion that absorbs and reflects light in a thermoplastic resin (see, for example, Patent Document 3). Yes.
However, Patent Document 3 has a problem that a white resin layer and a transparent diffusion layer must be formed, and the manufacturing method becomes complicated. There is also a problem of pinholes in the thermoplastic resin due to reheating.

In addition, in all the above-mentioned materials, when these materials are to be formed in the gap between the components, in any case, after forming a layer of the target material on the first member, It must be formed with the remaining parts. For this reason, there is also a problem that it is not convenient that a material is poured into a narrow gap formed in advance to make it function.

JP 2003-29314 A (Claims) Japanese Patent Application Laid-Open No. 2004-221169 (Claims) Japanese Patent Laying-Open No. 2006-23693 (Claims)

  As described above, when the conventional technology is used, there are problems such as a problem due to costumes, thermoplasticity, and the ability to flow into a narrow space.

  The present invention solves the problems so far, is white with high clothes, can shield microwaves such as light, and is poured into the gap between members, which is the most important element in the manufacture of precision machinery. It is an object of the present invention to provide a functional adhesive suitable for making precision machines, and to provide a light-shielding adhesive composition that can protect the interior from such an environment and protect the quality over a long period of time. .

  In order to achieve the above object, the light-shielding adhesive composition has an acrylic group composed of an acrylic monomer having a viscosity of 20000 cp or less at 25 ° C. and a number of functional groups in one molecule of 3 or less. This can be solved by using a light-shielding adhesive composition characterized by being obtained by adding 50 wt% or more and 150 wt% or less of a white pigment to an epoxy base adhesive having a number of 4 or less. Can be solved by using a light-shielding adhesive composition characterized in that is an oxide of titanium, and an acrylic monomer comprising an acrylic monomer having a viscosity of 20000 cp or less at 25 ° C. and a number of functional groups per molecule of 3 or less. A light-shielding adhesive group obtained by adding 50 wt% to 150 wt% of a white pigment and 0.5 wt% to 5 wt% of an organic oxide to a system adhesive It can be solved by using an object.

  According to the present invention, since the conventional thermoplastic resin is not used and the crosslinkable resin is used, it is possible to prevent the deterioration due to the reheated pinhole which has been a conventional problem, and the color. Because it is white, the costume is not inferior. In addition, since it can be poured into a narrow space at room temperature, it is possible to save the trouble of removing the solvent by diluting with a solvent and the trouble of heating. In addition, by using the light-shielding composition of the present invention, gamma rays having a shorter wavelength than visible light and electron beams such as X-rays can be shielded and reflected. This property has made it possible to protect precision instruments for a long time without deterioration.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

The light-shielding adhesive composition of the present invention can achieve both costume and light-shielding properties by adding a white color material to an adhesive that can be cured by applying reaction energy such as heat and light.

  Examples of the base adhesive include acrylic adhesives and epoxy adhesives. In particular, in the adhesive of the present invention, it is necessary to contain a large amount of an additive such as a white material because high light-shielding properties must be obtained.

  For this reason, it is more advantageous to make the viscosity of the adhesive alone as low as possible. In particular, when producing a precision machine, the flow characteristics such as the flowability with the parts of the entire composition are important, so the viscosity of a single base adhesive containing no additive is 20000 cp at room temperature (about 25 ° C.). It is preferable to keep it below.

  For example, when acrylic is used, a monomer having an acrylic or methacryl group and an initiator suitable for photocuring can be added. The adhesive thus obtained has photocurability.

The reason why it can be cured by light is that the monomer having an acrylic or methacrylic group of the adhesive transmits light and gives light energy to the initiator so that the photoreaction can be performed firmly.
However, the adhesive of the present invention requires light shielding properties. For this reason, photocurability will fall remarkably with the additive demonstrated later.

Therefore, when used at a very shallow depth, it can be used as it is, but especially when the adhesive is infiltrated into a deep part and hardened, the light does not penetrate to the deep part, so the thermosetting property is given to the adhesive. It will be necessary.
When thermosetting is imparted, the adhesive itself is warmed by the reaction heat when cured with light, and the reaction is deeper. In addition, since the deep part is likely to accumulate heat, there is a synergistic effect that the reaction is further facilitated and curing can be performed.

  An organic oxide is mentioned as a material added in order to use such heat curing together. The amount to be added is preferably in the range of 0.5 wt% to 5 wt% with respect to the monomer, and ideally in the range of 0.5 wt% to 3 wt%.

  Examples of the acrylic monomer of the acrylic adhesive shown above include acrylates having an acrylic group and methacrylates having a methacryl group, and those having a plurality of each group in one molecule. is there. In order to accelerate the curing reaction, it is advantageous to have many acrylic groups and methacrylic groups in one molecule. However, considering that the curing shrinkage must be controlled, acrylic groups in one molecule and methacrylic groups The number of groups is preferably 3 or less.

  If this amount is added, it can be hardened only by heat even if light does not reach. Moreover, when the reactivity of an acrylic group and a methacryl group was compared, the reactivity of an acrylic group is higher than that of a methacryl group. For this reason, in a system that does not contain an organic oxide, it is preferable to use only a monomer having an acrylic group in consideration of mass productivity.

  As the photopolymerization initiator, an acetophenone derivative and an α-aminoacetophenone derivative were used while paying attention to the absorption wavelength, but other initiators can be used as long as the intended conditions are satisfied.

Examples of organic oxides include tertiary butyl peroxyacrylate, tertiary butyl peroxybenzoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, and di (4-tert-butylcyclohexyl). ) Various derivatives including peroxydicarbonate can be used.

  Moreover, as an adhesive used as the base of this invention, as an epoxy adhesive, both a photocurable type and a thermosetting type can be selected, but an epoxy photocurable adhesive is an acrylic type adhesive. Since the reaction rate is slower than that of a photocurable resin, it is advantageous to select a thermosetting type in the case of epoxy.

  The epoxy adhesive can be made by mixing an epoxy monomer (epoxy resin) with an amine, acid anhydride or thiol curing agent. Since the epoxy monomer also tends to be highly viscous and has a tendency to increase curing shrinkage when it has too many functional groups, it is preferable to use a tetrafunctional or lower functional group.

  In particular, when a low viscosity is required, it is preferable to mix a liquid curing agent with a low-viscosity epoxy resin. However, if conditions permit, a base of a one-part epoxy adhesive in which one is solid and dispersed. It is also possible.

  As the epoxy monomer, various epoxies such as those containing aromatic groups, those composed of alkyl groups, and alicyclic epoxies can be used.

As an additive, any inorganic pigment for making it white can be used. In particular, titanium oxide was added to confirm the function expression.
The meaning of adding the white pigment is that white reflects the color, and it is considered that the hiding power of light or the like is high when the pigment is used. For this reason, the use of white can provide a function without deteriorating the surface costume.

  The amount of white pigment added is determined by the performance of not allowing light to pass through. Since it is a precision instrument, it is preferable to add such an amount that the transmittance is 0.5% or less at a thickness of about 100 micrometers.

  When trying to make the transmittance less than this, the effect was not improved even if more white pigment was added. Rather, the effect can be enhanced by adding aluminum powder as another filler. The aluminum powder can be used as an ordinary amorphous powder, but it is preferable to add a plate-like material if possible because an appropriate addition amount is required more than the aluminum having a plate-like shape. In consideration of stability, aluminum nitride obtained by nitriding aluminum can also be used.

  The plate-like aluminum powder is made by first laminating aluminum on a flat surface by a vacuum deposition method with a film thickness of about 0.2 nanometer to 0.5 nanometer, then peeling and crushing in a solvent in a wet manner. The target plate-like aluminum powder can be obtained.

  Since the flat aluminum powder can obtain a large surface area with a small amount, there is an effect that the ability to reflect light is high and the ability to shield light is also high. Further, it is possible to block light of about 0.05%, which is less than 0.5%, which could not be realized with white pigment alone.

  In addition, since it is based on a low-viscosity epoxy adhesive or acrylic adhesive, it can be easily cured and excellent in handling, and can be cured in a single process, so that the object can be achieved by a simple manufacturing method. In addition, since it functions as an adhesive, it can not only block light but also can block light while adhering. Therefore, it has become possible to express functions of two roles with just one.

In the production of precision parts, since the fixing can be achieved by pouring the adhesive into the gap and curing the adhesive, the realization of the product will progress significantly.
Hereinafter, the light-shielding adhesive composition of the present invention will be described in more detail based on examples.

Attempts were made to paste together two glass plates having a thickness of 100 mm, a thickness of 100 mm, a thickness of 100 mm, a thickness of 100 mm, and a thickness of 100 mm.
Examples of the light-shielding adhesive composition include sample 1: an adhesive containing titanium oxide and an acrylic adhesive containing only a photoinitiator, and sample 2: titanium oxide containing an acrylic adhesive containing a photoinitiator. Sample 3: An epoxy-based adhesive containing titanium oxide was prepared, and a light-shielding adhesive composition was poured into the gap between the plates at room temperature.
The adhesives of Sample 1 and Sample 2 were tried to be bonded by irradiating ultraviolet rays. Sample 3 was cured by heating.

As a result, in any case, the light-shielding adhesive composition flowed into the glass gap. When the light shielding property was evaluated with a gap of 100 micrometers, the transmittance was as good as 0.5% or less.
When the adhesion was evaluated, in the case of Sample 1, the one with a gap of 25 micrometers was cured and the adhesion was sufficient, but the one with 50 micrometers was in a state of being half-cured, and 100 micrometers. At the meter, uncured parts were scattered. In the case of Sample 2, both 25 micrometers and 50 micrometers were cured, but 100 micrometers was in a state of being half cured. This sample was again prepared in the same manner, and then heated and cured by heating. The sample was completely cured and adhesion was improved. This indicates that even when the film thickness is increased, it can be dealt with by adding an organic oxide. In the case of Sample 3, it was cured in all cases and adhesion was good.

  The addition amount of the white pigment made of titanium oxide was changed from 50 wt% to 150 wt% using the adhesives of Sample 2 and Sample 3. However, if the amount is substantially less than 50 wt%, the light cannot be used due to excessive transmission, and 150 wt%. Even when added, the transmittance was 0.5%, and no improvement in function was found.

Attempts were made to paste together two glass plates having a thickness of 100 mm, a thickness of 100 mm, a thickness of 100 mm, a thickness of 100 mm, and a thickness of 100 mm.
As the light-shielding adhesive composition, sample 1: an adhesive containing titanium oxide and plate-like aluminum powder and an acrylic adhesive containing only a photoinitiator, sample 2: titanium oxide and plate-like aluminum powder 3 types of adhesives containing a photoinitiator and an organic oxide in an acrylic adhesive, sample 3: an epoxy adhesive containing titanium oxide and plate-like aluminum powder The light-shielding adhesive composition was poured from the gap between the plates at room temperature.
The adhesive of Sample 1 was tried to be bonded by irradiating with ultraviolet rays. The adhesive of Sample 2 was cured using ultraviolet rays and heat. Sample 3 was cured by heating.

As a result, in all cases, the light-shielding adhesive composition flowed into the glass gap. When the light shielding property was evaluated with a gap of 100 micrometers, the transmittance was as good as 0.05% or less. The light-shielding performance has been greatly improved.
The aluminum powder added at this time had a film thickness of 20 to 50 nanometers and a particle size of about 4 micrometers. The amount of aluminum powder added was 10 wt% with respect to the adhesive base.

  In the case of the sample 1, the adhesiveness was somehow cured at 25 micrometers, but in the other cases it could not be sufficiently cured. In the case of Sample 2, since both light and heat were used, the adhesion was good. In the case of Sample 3, all adhered well.

Also, the amount of aluminum powder was added while observing the transmittance. However, if 0.5 wt% or more was added, a phenomenon that the transmittance was reduced appeared, and if 20 wt% was added, the transmission was almost completely suppressed. I also found out.
Since the function is substantially satisfied when 10 wt% is added, the optimum value for the amount of aluminum powder added is between 10 wt% and 20 wt%.

Claims (4)

A light-shielding adhesive composition that shields an electron beam from visible light,
An acrylic system composed of an acrylic monomer having a viscosity of 20,000 cp or less at 25 ° C. and a number of functional groups in one molecule of 3 or less,
Alternatively, add 50 wt% or more and 150 wt% or less of a white pigment with a particle size of 25 micrometers or less to an epoxy base adhesive with a viscosity of 20000 cp or less at 25 ° C and 4 or less epoxy groups in one molecule. A light-shielding adhesive composition characterized by being obtained. The light-shielding adhesive composition according to claim 1, wherein the white pigment is titanium oxide. Furthermore, 10 wt% to 20 wt% of plate-like aluminum having a thickness of 50 nanometers or less and a particle diameter of 25 micrometers or less is contained.
  The light-shielding adhesive composition according to claim 1, wherein the light-shielding adhesive composition is provided. Selected from tertiary butyl peroxyacrylate, tertiary butyl peroxybenzoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-tertiarybutylcyclohexyl) peroxydicarbonate organic peroxide shielding adhesive composition according to any one of claims 1 to 3, characterized in that it contains from 0.5 wt% or less 5 wt% to.