JP2006057069A - Adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive capable of constructing a strong bond of a material to be bonded by utilizing an unsaturated polyester resin produced by performing the esterification reaction of a carboxylic acid with a glycol, a polystyrene resin-melting effect of styrene monomer contained in a vinyl ester resin, a cross-linking reaction of an unsaturated polyester resin and the polymerization of the styrene monomer. <P>SOLUTION: This adhesive having both characteristics of a thermosetting resin and thermoplastic resin is provided by melting the polystyrene resin, putting it into the unsaturated polyester resin and vinyl ester resin, and completing the cross-linking and polymerization with the same peroxide compound catalysis, and further in the case that the material to be bonded is a polystyrene, it is possible to make the adhesive layer as a one-pieced material by melting a part of its surface on application so as to make the adhesive exhibiting a strong and short time bonding with high reliability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

      The present invention relates to an adhesive produced by melting a polystyrene resin body in an unsaturated polyester resin, and relates to an adhesive having the characteristics of thermosetting and thermoplasticity.

Technical background

As the bonding principle of the adhesive, there are the following representative ones.
(1) Internal diffusion The polymer molecules on the surface of the adherend are diffused to the other adherend surface or the molecular chain of the adhesive to form a bond between the plurality of polymer molecules. Its adhesion is determined by the number of molecules that diffuse into the molecular network. [Fig.1] Adhesion principle form-(1)
(2) Chemical bond A strong bond is caused by a chemical reaction between the functional group on the surface of the adherend and the reactive group of the adhesive. The strength of the bond depends on the chemical reaction form. This means that a styrene monomer having a double bond which is an unreacted group penetrates the surface, and then polymerization occurs by a chemical polymerization reaction. [Fig.2] Adhesion principle form- (2)
(3) Mechanical bonding When the surface of the adherend has unevenness, the surface of the other adherend and the adhesive part intervene and the unevenness portion meshes to cause a bond called an anchor effect. In this case, the adhesive is preferably liquid and has a low viscosity. [Fig.3] Adhesion principle diagram-(3)
The present invention is an adhesive that satisfies the principles of (1), (2), and (3).

Adhesives include water-soluble adhesives (eg, starch paste), water-dispersed adhesives (eg, emulsion type), solvent-type adhesives (eg: solvent-based rubber), and solventless adhesives (eg, epoxy) Resin), film-type adhesive (eg, phenol resin), paste adhesive (urethane resin), solid adhesive (eg, hot melt), and the like. Each of these adhesives has a single characteristic of thermosetting and thermoplastic properties,
There was no adhesive having the characteristics covering all the bonding principles (1), (2) and (3).

      In many cases, it is necessary to improve the surface condition of the adherend as a means for improving the adhesive strength. As a method for this, there is a method using a primer having an affinity for the adherend and the adhesive. However, this method requires a primer coating operation separately from the bonding operation, which is very complicated because it overlaps with the bonding operation. Met.

      This adhesive uses an unsaturated polyester resin, so that the styrene monomer contained therein melts a polystyrene resin such as styrene foam and keeps a stable liquid, and particularly when the adherend is a polystyrene resin, It follows the bonding principle of melting its surface. This is a method satisfying the bonding principle (1).

The styrene monomer contained in the unsaturated polyester resin becomes a cross-linking agent for curing the unsaturated polyester resin due to the action of the catalyst (peroxide), and at the same time, it is polymerized by the polymerization reaction of the monomers and is almost scattered as a solvent. Therefore, it is easy to deal with the environment and solvent treatment.
"Japanese Patent Application 2003-178778 "Japanese Patent Application 2004-212320 "Published by Japan Society for Materials Science Adhesives and Materials 1996.12.10" "Toyo Keizai Shinposha Adhesive Practical Knowledge 1996.5.23" “Nippon Jitsugyo Publishing Adhesive Technology Story 1997.2.28” "Nippon Kogyo Shimbun Polyester Resin Handbook 1988" "Tokyo Chemical Co., Ltd. Chemistry Dictionary 1998 Aki Ueki "Chemical Handbook of Chemical Society of Japan 1998" Yasuhiro Iwasawa "Industrial Research Committee Plastic Data Book 1999.12.1 Yukio Shimura

Representative examples of thermosetting resins used as adhesives include epoxy resins, acrylic resins, unsaturated polyester resins, and vinyl ester resins. Each of these thermosetting resins has problems. The problems are listed below.
(1) About an epoxy resin, a price is expensive, the viscosity of an adhesive agent is high, and the application | coating operation | work to the adherend surface is difficult. Furthermore, since it is difficult to adhere to a smooth surface, the surface of the adherend is preliminarily subjected to primer treatment or surface roughening, so that the work process is complicated and there are problems in terms of work efficiency and cost. In addition, it has the disadvantage of a long curing time and takes time to complete the work. In addition, the price was high. In particular, it did not meet the bonding principle (1).
(2) The acrylic resin has the disadvantages of being expensive as in the case of epoxy and having a long curing time and poor work efficiency. In particular, in the case where polystyrene resin is the adherend, there is a drawback that the surface must be primed or roughened. For this reason, the bonding operation is extremely complicated.
(3) When unsaturated polyester resin and vinyl ester resin are used alone without treatment, they have low-cost characteristics, and the liquid viscosity can be adjusted by the esterification process or styrene monomer%. Although it is very easy to handle in handling, it is only using the bonding principles (2) and (3), and if it is left as it is, the shrinkage rate at the time of curing is large, and the bonding surface due to the shearing force of the bonding interface caused by the shrinkage at the time of curing It has been pointed out that the adhesive strength is lowered due to the occurrence of breakage, and cannot be used for important adhesive applications. Moreover, although it has the advantage that the curing time is short, the curing time cannot be shortened because a sufficient time is required for the surface melting by the styrene monomer contained in the adhesion of the polystyrene resin.
(4) When the adherend is a polystyrene resin, in the adhesion with the thermosetting resin adhesive, the adherend is either applied with a primer or the surface is roughened. To date, there has been no adhesive suitable for a method of integrating the adhesive interface on the surface of the adherend in a single operation.
(5) There was no adhesive capable of adhering granules or powders of polystyrene resin, stone, wood, or the like to the concrete surface using the bonding principles (1), (2), and (3).

Means for Solving the Invention

The inventor has invented the following method as means for solving the problem.
It is well known that polystyrene resins melt and dissolve in styrene monomers, benzene, toluene, xylene, acetone, trichloroethylene, limonene and the like. In addition, thermosetting resins such as unsaturated polyester resins and vinyl ester resins are liquid materials containing a large amount of styrene monomer that melts polystyrene resin, and the styrene monomer is esterified by the action of a catalyst added for the purpose of resin curing. It is well known that crosslinking and monomer polymerization occur. Further, it is also known that other solvents do not cross-link or polymerize without reacting, remain or scatter and are environmentally undesirable. In view of these matters, the present inventor has developed means for developing an adhesive that covers all the bonding principles (1), (2), and (3) by melting a polystyrene resin, which is a thermoplastic resin, into an unsaturated polyester resin. Was invented. The present inventor preliminarily polymerized polystyrene resin and filler for the purpose of integration of the adherend, adhesive interface, and suppression of shrinkage during curing of the adhesive, liquid unsaturated polyester resin, or vinyl ester. The problem was solved by the method of dissolving in resin. As a result, we developed an adhesive with both sides of thermosetting resin and thermoplastic resin, which was not possible with conventional adhesives, surface roughening work on the polystyrene resin surface, which is a problem, All major problems such as integration, fast curability, and low cost have been improved. According to this adhesive, it can be applied to the adhesion of plate materials, atypical objects, granules, powders, etc., and has become an extremely effective means.

The invention's effect

In the present invention, it is a condition that a styrene monomer is contained as a component as a crosslinking agent for the purpose, and it is preferable to use an unsaturated polyester resin, a vinyl ester resin, etc. as an example of such a resin. It is also possible to add and use a monomer having a double bond in the molecule such as methacrylate.
These resins are compatible with styrene monomers esters produced by a dehydration reaction by the esterification reaction of an acid and an alcohol such as carboxylic acids (eg, maleic anhydride, phthalic anhydride) and polyhydric alcohols (ethylene glycol, propylene glycol). It must be a generic term for the unsaturated carboxylic acid used in part. In the description of the present invention, an unsaturated polyester resin obtained by esterification with carboxylic acid (maleic anhydride, phthalic anhydride) and propylene glycol and compatibility with styrene monomer is used.
When the polystyrene resin body is an adherent, the present inventor has a long time until the styrene monomer contained in the unsaturated polyester resin gels in the process of curing the unsaturated polyester resin (hereinafter referred to as a liquid time zone). The longer the residence, the more the surface of the adherend was melted, and it was found that the adherend and the adhesive interface were integrated by gelation by curing of the unsaturated polyester resin, curing and polymerization of styrene monomers, and the adhesion was completed. In this liquid time zone, the longer the time zone, the more the surface of the polystyrene resin adherend is melted, and finally it is partially incorporated into the crosslink of the unsaturated polyester resin which is a thermosetting resin as an adhesive. It has been found that the adhesion is improved by moving the adhesive surfaces to each other in the liquid time zone of the unsaturated polyester resin. However, in this method, the time until curing is extremely long, and the function as an adhesive intended by the present inventor is not suitable. Therefore, as described above, if the polystyrene resin of the same material as the polystyrene resin adherend that has already completed the polymerization reaction is previously melted in the unsaturated polyester resin, the melting time of the polystyrene resin adherend surface can be reduced. I found that it can be extremely shortened. That is,

(1) As described in the section of internal diffusion, “a polymer molecule on the surface of an adherend is diffused on the surface of another adherend or on the molecular chain of the adhesive to form a bond between a plurality of polymer molecules. Its adhesive strength is determined by the number of molecules that diffuse into the molecular mesh. ”
Furthermore, since the adhesive according to the present invention is polymerized by reaction except for the filler and the like, it is different from the melting of the surface of the adherend by the solvent, and other adherends (for example, tile, concrete, mortar, Since it penetrates and hardens in the gaps between wood, stone, paper, etc.), it can be bonded in the same manner as a hot melt adhesive.

The unsaturated polyester resin used in the present invention is an unsaturated polyester resin, vinyl ester resin or the like that has undergone an esterification reaction, and uses a styrene monomer as a main cross-linking agent, such as an acrylic monomer. The addition of a monomer having a double bond is also included. Hereinafter, the adhesive will be described on behalf of an unsaturated polyester resin produced using a carboxylic acid and a polyhydric alcohol.
The unsaturated polyester resin in this example is an ester obtained by esterifying maleic anhydride (unsaturated acid having a double bond) and phthalic anhydride (saturated acid not having a double bond) at 6 mol to 4 mol. 40 parts by weight of a styrene monomer compatible with 100 parts by weight of the ester after the esterification reaction. This is described as an example of an unsaturated polyester resin. This unsaturated polyester resin is stable at room temperature by the addition of a polymerization inhibitor, and only when a peroxide catalyst (such as methyl ethyl ketone peroxide) and an accelerator (such as cobalt naphthenate) is added causes high-temperature crosslinking and polymerization reaction from room temperature. The reaction is completed by polymerizing to form a three-dimensional structure. In that case, it is known that the excess styrene monomer which was not used as a crosslinking agent superposes | polymerizes and polystyreneizes.

  On the other hand, when the adherend is a polystyrene resin, the surface of the styrene monomer contained in the unsaturated polyester resin melts with time. However, its melting speed is slow, and if the unsaturated polyester resin has cured before it melts sufficiently,

(1) Internal diffusion does not occur and causes poor adhesion. In this regard, the inventor has theoretically considered that an adhesive that exhibits a thermosetting and thermoplastic performance obtained by melting a polystyrene resin in an unsaturated polyester resin in advance during the production of the adhesive is effective in improving the adhesive strength. Was also found to be optimal. This adhesive production is extremely preferable as an adhesive production because it is easy to perform the melting step at room temperature.

Next, the manufacturing procedure and the like of this adhesive will be described.
0.1 to 10 parts by weight of polystyrene resin is added to 100 parts by weight of unsaturated polyester resin and mixed with stirring. The polystyrene resin to be used is a polystyrene foam that is a foamed product, and those having an expansion ratio of 50 times or more are most preferable in use. The reason is that these foams are in the form of a thin film and are easy to melt, and may be in the form of polystyrene resin powder. As described above, since the polystyrene resin has undergone the polymerization reaction, it does not shrink when the adhesive is cured, so the higher the amount added, the more the shrinkage caused by the crosslinking reaction of the unsaturated polyester resin and the polymerization of the styrene monomer when the adhesive is cured. It can be made small, can also be effective as a stress buffering agent, and has an effect of preventing a decrease in adhesive strength. That is, since the shearing force after curing on the bonding surface can be reduced, it is extremely preferable to melt the polystyrene resin, and the adhesion-enhanced curing is exhibited.

The polystyrene resin is preferably mixed with a filler (hereinafter referred to as “filler”) in order to reduce the shrinkage generated during curing of the adhesive and to prevent the fluidity of the adhesive. It is preferable to add in the range of 10 to 30 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin and polystyrene resin mixture, and it is usually preferable to mix the resin mixture in a mixer. Examples of the filler are preferably fine particles such as coal ash (10 to 20 μ), calcium carbonate, carbon black, titanium white, and the like.
The adhesive produced in this way lowers the shrinkage rate after curing of the unsaturated polyester resin itself from 5 to 7% (depending on the amount of styrene monomer added and the amount of unsaturated carboxylic acid) to less than half the shrinkage rate. Is possible. A polystyrene resin, which is a thermoplastic resin, and an inorganic filler are dispersed inside the unsaturated polyester resin, and it is a highly viscous material that is in a liquid state at room temperature under normal storage conditions. Also, pigments, short fibers, etc. can be added.

  This adhesive is mainly made of unsaturated polyester resin, polystyrene resin, and inorganic filler, and the curing time is adjusted by adjusting the amount of use with catalyst and accelerator, and it is cured in the temperature range from low temperature to high temperature. I can do it. These are methods based on the selection of a catalyst and an accelerator, and in general, the adhesive is preferably used in the range of 5 ° C to 50 ° C. Further, it is easy to adjust the curing time depending on the amount of the catalyst added.

Next, it was described that the adhesive is cured by the addition of a catalyst and an accelerator. The interface state of the adherend and adhesive after curing will be described.
When the adherend is a polystyrene resin, when the adhesive is applied to the adherend surface, the styrene monomer contained in the unsaturated polyester resin melts over time with the polystyrene resin on the surface. However, in the stationary state, the melting takes time, and mixing with the unsaturated polyester resin is extremely difficult, and it is extremely difficult to satisfy the condition of the bonding principle (1). It is difficult to mix unsaturated polyester resin and polystyrene resin on the bonding surface, which is the purpose of this adhesive, and it is extremely difficult to exert the adhesive force due to mixing especially in a short time, which causes poor adhesion It becomes. In view of this phenomenon, the present inventor has determined that an adhesive produced by previously melting an unsaturated polyester resin with a polystyrene resin can solve the problem. The adhesive interface after curing was in a state where an adhesive structure based on the adhesion theory shown in FIGS. 1, 2, and 3 was constructed, and thus, an unprecedented strong adhesive force and durability could be exhibited.

  Next, when the adherend is other than polystyrene resin, it is preferable that the adherend surface is rough. As adherends, metal products, concrete products, asphalt, stone materials, tiles and other inorganic products, and paper, wood, carbon fibers, glass fibers and other fiber products can be easily and durablely bonded. I can do it. In this case, the bonding principle (3) is used, and the thermosetting adhesive is generally based on the same principle as the bonding principle, but it has the advantage of being cheaper than other adhesives. It is. In advance, by melting a polystyrene resin in an unsaturated polyester resin (liquid), the surface of the polystyrene adherend to be bonded in the process of adding a peroxide catalyst to the polystyrene resin molten unsaturated polyester resin and curing it is polystyrene resin. At the same time as melting by the styrene monomer contained in the molten unsaturated polyester resin, the means for integrating the adhesive surface of the polystyrene adherend by polymerization of the styrene monomer and crosslinking reaction of the unsaturated polyester resin is used.

3 parts by weight of foamed polystyrene (polystyrene resin foam) is added to 100 parts by weight of unsaturated polyester resin (Japan Composite Co., Ltd., brand R-235: including accelerator), and a stirring mixer Was sufficiently dissolved. Next, 20 parts by weight of coal ash (fly ash having a diameter of about 10 microns) was added to 100 parts by weight of the kneaded product and kneaded sufficiently. The adhesive thus produced has a configuration in which a thermosetting resin, a thermoplastic resin, and a filler are mixed.
This adhesive already contains an accelerator and is cured only with a catalyst. Moreover, it is easy to adjust the curing time depending on the amount of the catalyst added. For example, 1% is added to 100 parts of the catalyst, methyl ethyl ketone peroxide (manufactured by Nippon Kayaku Co., Ltd.) and the adhesive capacity. In such a case, the gelation is performed at 20 ° C. for 15 minutes and the fluidity is lost. Incidentally, when 0.5% is added, gelation occurs at 20 ° C. for 40 minutes and the fluidity is lost. During this time, when the adherend is a polystyrene resin, a part of the surface melt of the polystyrene resin adherend is melted and melt-bonded with the unsaturated polyester resin and the polystyrene resin melted therein, and further the unsaturated polyester. Combined with the polymerization of the styrene monomer that was not involved in the crosslinking of the resin, it exhibited adhesion that met the perfect adhesion theory (1).

      Adhesion tests of various materials such as polystyrene plates were conducted. The test method was measured according to the adhesive strength test JISK6850 using a Hokkaido Industrial Experiment Station adhesive strength measuring device. Ten test pieces were used for each case, and the average value was displayed. The test piece was prepared by adding the curing agent shown in the table to the above adhesive and stirring it well for 2 minutes, then applying the adhesive to each side of the two test pieces, and combining the applied surfaces. It was left at room temperature at 20 ° C. for 24 hours. Thereafter, the sample was kept at 60 ° C. for 24 hours and then taken out, and further left at 20 ° C. for 24 hours for measurement. For comparison, an adhesion test using an unsaturated polyester resin alone was also performed on some test pieces in the same manner, and the results are shown in Table 1 at the same time. The test items are

It was shown to.

a: Adhesion of polystyrene resin plate × polystyrene resin plate Adhesive used: Unsaturated polyester resin (R-235) alone Curing agent: 1.0% (vs. resin) Gel time: 15 minutes / 20 ° C.
b: Adhesion of polystyrene resin plate x polystyrene resin plate Adhesive used: Unsaturated polyester resin (R-235) alone Curing agent: 0.5% (vs. resin) Gel time: 40 minutes / 20 ° C
c: Adhesion of polystyrene resin plate × polystyrene resin plate Adhesive used: Adhesive Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C.
d: Adhesion of polystyrene resin plate × polystyrene resin plate Adhesive used: Adhesive Curing agent: 0.7% (vs. resin) Gel time: 50 minutes / 20 ° C.
e: Polystyrene resin plate x tile Adhesive used: Adhesive Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C
f: Polystyrene resin plate × tile Adhesive: Unsaturated polyester resin (R-235) alone Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C.
g: Polystyrene resin plate × concrete plate Adhesive used: Adhesive Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C.
h: Polystyrene resin plate × plywood Adhesive used: Adhesive Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C.
i: Polystyrene resin plate × plywood Adhesive used: Unsaturated polyester resin (R-235) alone Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C.
j: Polystyrene resin plate x smooth glass plate
Use adhesive: Adhesive
Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C
k: polystyrene resin plate x smooth glass plate
Adhesive used: Unsaturated polyester resin (R-235) alone
Curing agent: 1.5% (vs. resin) Gel time: 15 minutes / 20 ° C

1% of a peroxide catalyst (methyl ethyl ketone peroxide: Nippon Kayaku Co., Ltd. Kayamek) is added to 100 parts of the adhesive according to the present invention, and the mixture is stirred for 2 minutes and then applied onto a concrete plate with a roll. Silica sand particles were sprayed thereon and allowed to stand at 25 ° C. for 1 hour, after which the resin was confirmed to cure, and then the excess silica sand particles were removed. A strong non-slip layer was formed on the concrete surface by curing the adhesive.
Since this adhesive exhibits an excellent effect for bonding with asphalt, it was evaluated to be effective in preventing road-related slipping. Silica sand granule is an example, and as an alternative material, it was confirmed that coal ash, abrasive powder, waste glass crushed material, ore, shell, etc. can be used as an example.

      As a result of the above tests, it was proved that the adhesive according to the present development was in accordance with the bonding principle and was extremely excellent in use.

Bonding principle sectional view-(1) Bonding principle form sectional view-(2) Bonding principle cross-sectional view-(3)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhering material 2 Adhesive layer 3 Polystyrene melting part 4 Polyester resin solidification part 5 Polystyrene resin melt and styrene monomer polymer mixing part 6 Styrene monomer cross-linking part 7 Styrene monomer polymerization part 8 Adhesive (adhesive layer)
9 Anchor part

Claims (1)

        An adhesive prepared by subjecting a carboxylic acid and a glycol to an esterification reaction, and adjusting a main material obtained by melting a polystyrene resin having undergone a polymerization reaction into a thermosetting resin dissolved in a styrene monomer.

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